Reduced Virus Shedding Research Articles

A nonhuman primate model for genital herpes simplex virus 2 infection that results in vaginal vesicular lesions, virus shedding, and seroconversion.

The most commonly used animal models for evaluating the efficacy of HSV-2 candidate vaccines are mice and guinea pigs. While numerous HSV-2 vaccine candidates have been tested in these animals and were effective in reducing disease and mortality, these results did not predict the effectiveness of the vaccines in human trials. Infection of rhesus macaques rarely results in lesions or HSV-2 specific antibody responses. In seeking an animal model that better recapitulates human disease and that might be more predictive of the efficacy of prophylactic vaccines than mice and guinea pigs, we evaluated Cebus apella (C. apella), a New World primate, in an HSV-2 genital infection model. Infectious HSV-2 was cultured from vaginal swabs from all 4 animals for 9-14 days after intravaginal inoculation of HSV-2 seronegative monkeys. Two of 4 monkeys had vesicular lesions in the vagina or vulva. No neurological symptoms were noted. Recurrent lesions and HSV-2 DNA shedding after acute disease resolved was infrequent. UV irradiation of the genital area did not induce recurrent genital lesions or virus shedding. All 4 monkeys developed HSV-2 neutralizing antibodies as well as virus-specific CD4 and CD8 T cell responses. Reinfection of animals 15 to 19 months after primary infection did not result in lesions; animals had reduced virus shedding and a shorter duration of shedding compared with that during primary infection, suggesting that primary infection induced protective immunity. Primary fibroblasts from C. apella monkeys supported the growth of HSV-2 in vitro; in contrast, HSV-2 did not replicate above the titer of the input inoculum in fibroblasts from rhesus macaques. These observations suggest that the C. apella monkey has potential to serve as a model for evaluating the efficacy of prophylactic vaccines, antivirals, or monoclonal antibodies to HSV-2.

Therapeutic prime/pull vaccination of HSV-2-infected guinea pigs with the ribonucleotide reductase 2 (RR2) protein and CXCL11 chemokine boosts antiviral local tissue-resident and effector memory CD4+ and CD8+ T cells and protects against recurrent genital herpes.

Following acute herpes simplex virus type 2 (HSV-2) infection, the virus undergoes an asymptomatic latent infection of sensory neurons of dorsal root ganglia (DRG). Chemical and physical stress cause intermittent virus reactivation from latently infected DRG and recurrent virus shedding in the genital mucosal epithelium causing genital herpes in symptomatic patients. While T cells appear to play a role in controlling virus reactivation from DRG and reducing the severity of recurrent genital herpes, the mechanisms for recruiting these T cells into DRG and the vaginal mucosa (VM) remain to be fully elucidated. The present study investigates the effect of CXCL9, CXCL10, and CXCL11 T-cell-attracting chemokines on the frequency and function of DRG- and VM-resident CD4+ and CD8+ T cells and its effect on the frequency and severity of recurrent genital herpes in the recurrent herpes guinea pig model. HSV-2 latent-infected guinea pigs were immunized intramuscularly with the HSV-2 ribonucleotide reductase 2 (RR2) protein (Prime) and subsequently treated intravaginally with the neurotropic adeno-associated virus type 8 expressing CXCL9, CXCL10, or CXCL11 chemokines to recruit CD4+ and CD8+ T cells into the infected DRG and VM (Pull). Compared to the RR2 therapeutic vaccine alone, the RR2/CXCL11 prime/pull therapeutic vaccine significantly increased the frequencies of functional tissue-resident and effector memory CD4+ and CD8+ T cells in both DRG and VM tissues. This was associated with less virus in the healed genital mucosal epithelium and reduced frequency and severity of recurrent genital herpes. These findings confirm the role of local DRG- and VM-resident CD4+ and CD8+ T cells in reducing virus shedding at the vaginal site of infection and the severity of recurrent genital herpes and propose the novel prime-pull vaccine strategy to protect against recurrent genital herpes.IMPORTANCEThe present study investigates the novel prime/pull therapeutic vaccine strategy to protect against recurrent genital herpes using the latently infected guinea pig model. In this study, we used the strategy that involves immunization of herpes simplex virus type 2-infected guinea pigs using a recombinantly expressed herpes tegument protein-ribonucleotide reductase 2 (RR2; prime), followed by intravaginal treatment with the neurotropic adeno-associated virus type 8 expressing CXCL9, CXCL10, or CXCL11 T-cell-attracting chemokines to recruit T cells into the infected dorsal root ganglia (DRG) and vaginal mucosa (VM) (pull). We show that the RR2/CXCL11 prime-pull therapeutic vaccine strategy elicited a significant reduction in virus shedding in the vaginal mucosa and decreased the severity and frequency of recurrent genital herpes. This protection was associated with increased frequencies of functional tissue-resident (TRM cells) and effector (TEM cells) memory CD4+ and CD8+ T cells infiltrating latently infected DRG tissues and the healed regions of the vaginal mucosa. These findings shed light on the role of tissue-resident and effector memory CD4+ and CD8+ T cells in DRG tissues and the VM in protection against recurrent genital herpes and propose the prime-pull therapeutic vaccine strategy in combating genital herpes.

Attenuation and molecular characterization of fowl adenovirus 8b propagated in a bioreactor and its immunogenicity, efficacy, and virus shedding in broiler chickens

Background and Aim: Live-attenuated vaccines are the most successful type of vaccine and could be useful in controlling fowl adenovirus (FAdV) 8b infection. This study aimed to attenuate, molecularly characterize, and determine the immunogenicity, efficacy, and challenge virus shedding in broiler chickens. Materials and Methods: The FAdV 8b isolate (UPM08136) was passaged onto chicken embryo liver (CEL) cells until attenuation. We sequenced and analyzed the hexon and fiber genes of the passage isolates. The attenuated bioreactor-passage isolate was inoculated into 1-day-old broiler chickens with (attenuated and inactivated) and without booster groups and challenged. Body weight (BW), liver weight (LW), liver: body weight ratio (LBR), FAdV antibody titers, T-lymphocyte subpopulation in the liver, spleen, and thymus, and challenge virus load and shedding were measured. Results: Typical cytopathic effects with novel genetic changes on CEL cells were observed. The uninoculated control-challenged (UCC) group had significantly lower BW and higher LW and LBR than the inoculated groups. A significantly higher FAdV antibody titer was observed in the challenged non-booster and attenuated booster groups than in the UCC group. T cells in the spleen and thymus of the liver of inoculated chickens were higher than uninoculated control group levels at all-time points and at different times. A significantly higher FAdV challenge virus load was observed in the liver and shedding in the cloaca of UCC chickens than in non-booster chickens. Conclusion: The FAdV 8b isolate was successfully attenuated, safe, and immunogenic. It reduces virus shedding and is effective and recommended as a vaccine against FAdV infection in broiler chickens. Keywords: antibodies, attenuation, fowl adenovirus 8b, T lymphocytes, vaccines, virus shedding.

Protection of Chickens against H9N2 Avian Influenza Isolates with a Live Vector Vaccine Expressing Influenza Hemagglutinin Gene Derived from Y280 Avian Influenza Virus.

Since the outbreak of the H9N2/Y439 avian influenza virus in 1996, the Korean poultry industry has incurred severe economic losses. A novel possibly zoonotic H9N2 virus from the Y280-like lineage (H9N2/Y280) has been prevalent in Korea since June 2020, posing a threat to the poultry sector. Rapid mutation of influenza viruses urges the development of effective vaccines against newly generated strains. Thus, we engineered a recombinant virus rHVT/Y280 to combat H9N2/Y280. We integrated the hemagglutinin (HA) gene of the H9N2/Y280 strain into the US2 region of the herpesvirus of turkeys (HVT) Fc126 vaccine strain, utilizing CRISPR/Cas9 gene-editing technology. The successful construction of rHVT/Y280 was confirmed by polymerase chain reaction and sequencing, followed by efficacy evaluation. Four-day-old specific pathogen-free chickens received the rHVT/Y280 vaccine and were challenged with the H9N2/Y280 strain A21-MRA-003 at 3 weeks post-vaccination. In 5 days, there were no gross lesions among the vaccinated chickens. The rHVT/Y280 vaccine induced strong humoral immunity and markedly reduced virus shedding, achieving 100% inhibition of virus recovery in the cecal tonsil and significantly lowering tissue viral load. Thus, HVT vector vaccines expressing HA can be used for protecting poultry against H9N2/Y280. The induction of humoral immunity by live vaccines is vital in such cases. In summary, the recombinant virus rHVT/Y280 is a promising vaccine candidate for the protection of chickens against the H9N2/Y280.

Cytokine expression, protection and shedding reduction induced by the combination of lipopolysaccharide with Montanoid ISA71 in oil-based Newcastle disease vaccine

Oil-based inactivated ND vaccines are a commonly used control strategy for this endemic disease in Egypt. One of the major limitations of these inactivated vaccines is the time taken to develop a protective response in vaccinated birds. In the present study, we aimed to formulate an inactivated oil-based ND vaccine incorporated with lipopolysaccharide (LPS) that stimulates the early onset innate response to inactivated vaccines via proinflammatory cytokine production. Five groups of 21-day old SPF chicks were reared in isolators and were treated as follows: G1: Montanoid ISA71 adjuvanted NDV vaccinated group, G2: LPS and Montanoid ISA71 adjuvanted NDV vaccinated group, G3: LPS and Montanoid ISA71 with phosphate buffer saline received group and two non-vaccinated control groups. NDV specific antibodies and cell mediated immune responses were evaluated by hemagglutination inhibition and lymphocyte proliferation tests, respectively. Transcriptional responses of the TLR4, IFN-γ and IL-2 genes were analyzed in peripheral blood mononuclear cells (PBMCs) following vaccination by qRT-PCR. Protection % was determined after challenge with a lethal strain of NDV 106 EID50/0.5 ml. Viral shedding was assessed on oropharyngeal swabs by qRT-PCR and infectivity titration on SPF-ECE. The results revealed that the incorporation of LPS with ISA71 in the oil-based ND vaccine induced a synergistic response confirmed by significant humoral and lymphoproliferative responses with a significant increase in Th1 cytokine transcripts. The simultaneous use of both adjuvants in G2 demonstrated complete protection and a significant reduction in viral shedding compared to the ISA71-adjuvated ND vaccine in G1, which conferred 90 % protection.

Protective effectiveness of two vaccination schemes against the prevalent Egyptian strain of Newcastle disease virus genotype VII.

Despite the strict preventive immunization used in Egypt, Newcastle disease remained a prospective risk to the commercial and backyard chicken industries. The severe economic losses caused by the Newcastle disease virus (NDV) highlight the importance of the trials for the improvement and development of vaccines and vaccination programs. In the present study, we evaluated the effectiveness of two vaccination schemes for protection against the velogenic NDV (vNDV) challenge. Four groups (A-D) of commercial broiler chickens were used. Two groups (G-A and G-B) were vaccinated with priming live HB1 GII simultaneously with inactivated GVII vaccines at 5 days of age, then boosted with live LaSota GII vaccine in group A and live recombinant NDV GVII vaccine in group B on day 16. Groups A to C were challenged with NDV/Chicken/Egypt/ALEX/ZU-NM99/2019 strain (106 Embryo infective dose 50/0.1 ml) at 28 days of age. Two vaccination schemes achieved 93.3% clinical protection against NDV with body gain enhancement; whereas, 80% of the unvaccinated-challenged birds died. On day 28, the mean HI antibody titers were 4.3 ± 0.33 and 5.3 ± 0.33 log2 in groups A and B, respectively. As well as both programs remarkably reduced virus shedding. The two vaccination schemes displayed close protection efficacy against the vNDV challenge. Therefore, using the combination of a live attenuated vaccine with an inactivated genetically matched strain vaccine and then boosting it with one of the available live vaccines could be considered one of the most effective programs against current field vNDV infection in Egypt.

Effect of Vaccination on Distribution and Immune Response of Avian Influenza Virus H9N2 in Coturnix coturnix.

Influenza viruses can multiply in quails and be transmitted to other animal species. As vaccination reduces virus shedding in chickens, the effect of the killed H9N2 avian influenza virus (AIV) on tissue distribution and virus shedding was evaluated in quails. One hundred 20-day-old quails were divided into six equal groups, kept in separate pens, and fed ad libitum. Before vaccination, blood samples were randomly collected from the wing veins. Four groups were vaccinated with the inactivated H9N2 Razi Institute vaccine at 21 days subcutaneously at the back of neck. Three weeks later, two groups were re-vaccinated. Two weeks later, at the age of 56 days, three groups were challenged with 100 μL of allantoic fluid containing 105 EID50 H9N2 through the oculonasal route. Blood samples were collected from quails at 42, 56, 63, and 70 days from each group to determine AIV antibodies by the hemagglutination inhibition test. Three quails were randomly selected and euthanized from each group on days 1, 3, and 6 post-inoculation (PI). Tissue samples were collected, and the RT-PCR test was performed. No clinical signs or gross lesions existed in any of the groups during the experiment. However, the virus was detected in different tissues on the first, third, and sixth days after the challenge in unvaccinated challenged birds. Virus detection was significantly more frequent in the quails vaccinated once and challenged than in the twice-vaccinated challenged group (P≤0.05). On the third day of PI, the virus was detected in some organs of the challenged groups. On the sixth day of PI, the virus was detected only in the lungs of two unvaccinated and once-vaccinated challenged birds. It was concluded that the vaccination of quails against AIV H9 is necessary to protect them from clinical signs, as well as respiratory tract and intestine replication. Two-time vaccination significantly protects the respiratory and intestine tracts, compared to one-time vaccination (P≤0.05).

Efficacy of recombinant H5 vaccines delivered in ovo or day of age in commercial broilers against the 2015 U.S. H5N2 clade 2.3.4.4c highly pathogenic avian Influenza virus

BackgroundAvian influenza is a highly contagious, agriculturally relevant disease that can severely affect the poultry industry and food supply. Eurasian-origin H5Nx highly pathogenic avian influenza viruses (HPAIV) (clade 2.3.4.4) have been circulating globally in wild birds with spill over into commercial poultry operations. The negative impact to commercial poultry renewed interest in the development of vaccines against these viruses to control outbreaks in the U.S.MethodsThe efficacy of three recombinant H5 vaccines delivered in ovo or day of age were evaluated in commercial broilers challenged with the 2015 U.S. H5N2 clade 2.3.4.4c HPAIV. The recombinant vaccines included an alphavirus RNA particle vaccine (RP-H5), an inactivated reverse genetics-derived (RG-H5) and recombinant HVT vaccine (rHVT-AI) expressing H5 hemagglutinin (HA) genes. In the first experiment, in ovo vaccination with RP-H5 or rHVT-AI was tested against HPAI challenge at 3 or 6 weeks of age. In a second experiment, broilers were vaccinated at 1 day of age with a dose of either 107 or 108 RP-H5, or RG-H5 (512 HA units (HAU) per dose).ResultsIn experiment one, the RP-H5 provided no protection following in ovo application, and shedding titers were similar to sham vaccinated birds. However, when the RP-H5 was delivered in ovo with a boost at 3 weeks, 95% protection was demonstrated at 6 weeks of age. The rHVT-AI vaccine demonstrated 95 and 100% protection at 3 and 6 weeks of age, respectively, of challenged broilers with reduced virus shedding compared to sham vaccinated birds. Finally, when the RP-H5 and rHVT vaccines were co-administered at one day of age, 95% protection was demonstrated with challenge at either 3 or 6 weeks age. In the second experiment, the highest protection (92%) was observed in the 108 RP-H5 vaccinated group. Significant reductions (p < 0.05) in virus shedding were observed in groups of vaccinated birds that were protected from challenge. The RG-H5 provided 62% protection from challenge. In all groups of surviving birds, antibody titers increased following challenge.ConclusionsOverall, these results demonstrated several strategies that could be considered to protected broiler chickens during a H5 HPAI challenge.

922. Cost-effectiveness of baloxavir marboxil versus oseltamivir or no treatment for the management of influenza in the United States

Abstract Background Influenza poses a significant burden that can be effectively mitigated with antivirals. Baloxavir marboxil is an oral, single dose first-in-class endonuclease inhibitor that improves influenza symptoms and rapidly reduces virus shedding, shortening the infectious period and potentially reducing viral transmission. This study used real-world data to inform a cost-effectiveness (CE) model of antiviral treatment with baloxavir vs oseltamivir or no treatment. Methods A decision tree CE model was developed for seasonal influenza between 2018 and 2020. Patients aged 12 and older could receive baloxavir, oseltamivir or no treatment (Figure 1). Outcomes included complications, recovery and death. Patient profile and characteristics, complications and costs were derived from the Merative™ MarketScan® Research Databases, including US commercial claims, Medicare and Medicaid Supplemental databases. Healthcare resource use included outpatient visits, hospitalizations and intensive care unit admissions. Clinical inputs, recovery rates and utilities were derived from the literature. The base case model used a lifetime time horizon with 3.0% discounting for costs and 2.7% for quality-adjusted life-years (QALYs), assuming no transmission reduction. A subgroup analysis was conducted for otherwise healthy (OwH) and high-risk groups; scenario analyses explored the impact of reduced viral transmission with baloxavir. Results In the base case analysis, baloxavir resulted in an incremental CE ratio (ICER) of $7788/QALY vs oseltamivir and $311/QALY vs no treatment; subgroup analyses showed even greater CE in the high-risk population (Table 1). Scenario analyses showed increasing net monetary benefit (NMB) with incremental reductions in viral transmission with baloxavir, where a 5% reduction in transmission yielded a NMB for baloxavir of $4153 vs oseltamivir and $13,098 vs no treatment (Figure 2). Conclusion This real-world evidence-driven model showed that baloxavir is cost-effective vs oseltamivir or no treatment from a US payer perspective. Transmission reductions with baloxavir can have a substantial health economic benefit, and baloxavir may play an important role in management of seasonal influenza and pandemic preparedness. Disclosures Svenn Hansen, n/a, F. Hoffman La Roche: Employee|F. Hoffman La Roche: Stocks/Bonds Shih-Chen Cheng, M.S., P.h.D, Genentech/F. Hoffman La Roche: Genentech Employee|Genentech/F. Hoffman La Roche: Stocks/Bonds Andy Surinach, MPH, Genentech/Roche: employee of Genesis Research which receives funding from Genentech/Roche for consulting services Vince Yau, PhD, Genentech/F. Hoffman La Roche: Genentech Employee|Genentech/F. Hoffman La Roche: Stocks/Bonds Jennie H. Best, PhD, Genentech: Stocks/Bonds Hassan Zaraket, PhD, F. Hoffman La Roche: Employee|F. Hoffman La Roche: Stocks/Bonds Hao Zhou, PhD, Genentech/F. Hoffman La Roche: Genentech Employee|Genentech/F. Hoffman La Roche: Stocks/Bonds Marie-Helene Blanchet Zumofen, PhD MBA, F. Hoffman La Roche: Employee|F. Hoffman La Roche: Stocks/Bonds

A novel recombinant S-based subunit vaccine induces protective immunity against porcine deltacoronavirus challenge in piglets.

As an emerging porcine enteropathogenic coronavirus that has the potential to infect humans, porcine deltacoronavirus (PDCoV) is receiving increasing attention. However, no effective commercially available vaccines against this virus are available. In this work, we designed a spike (S) protein and receptor-binding domain (RBD) trimer as a candidate PDCoV subunit vaccine. We demonstrated that S protein induced more robust humoral and cellular immune responses than the RBD trimer in mice. Furthermore, the protective efficacy of the S protein was compared with that of inactivated PDCoV vaccines in piglets and sows. Of note, the immunized piglets and suckling pig showed a high level of NAbs and were associated with reduced virus shedding and mild diarrhea, and the high level of NAbs was maintained for at least 4 months. Importantly, we demonstrated that S protein-based subunit vaccines conferred significant protection against PDCoV infection.

Evaluation of protective immunity in chickens vaccinated with combined IB H120/D274 and IB H120 against IS/1494/06 in Iran

Infectious bronchitis virus (IBV) has a variety of serotypes that cause many problems in the poultry industry. Two H120 and H120-D274 live vaccines were evaluated against strain IS/1494/06 (variant 2) infectious bronchitis virus challenge. The study aimed to determine whether it is possible to achieve success in controlling disease symptoms and pathological lesions and reducing virus shedding by combining two types of vaccines against different severities of the Poultry Infectious Bronchitis Virus. After random selection of 100 SPF chickens, four 25 chicks/group experimental groups were arranged in the H120 (IB-H120, Intervet®; Serial No: **** at 1st day + Booster 14th day + Challenged with IS/1494/06- 14 DPV), H120-D274 (Poulvac® IB Primer at 1st day + Booster 14th day + Challenged with IS/1494/06- 14 DPV), Control (No vaccine and No Challenge), and Challenged (No vaccine + Challenge). After euthanasia of the animals on the 42nd day of the research, serum neutralization (days 14, 28, and 42), ELISA (14 days after the booster vaccine and before challenged), Ciliostasis (7 days after the booster vaccine and seven days after challenged) and pathological lesion scores were evaluated on day 14 after being infected with IS/1494/06 type 2 strain (day 42). Also, the virus shedding was monitored by real-time RT-PCR. Infection with the IS/1494/06 variant2 strain showed high to moderate ciliostasis and pathologic scores. All groups that received the IB-H120-D274 vaccine had fewer lesions relatively. The IB-H120-D274 vaccinated groups showed the highest protection rates and high protection scores (70.3) compared to the IB-H120 vaccine groups (24.4). The virus shedding was significantly reduced in groups that received the H120-D274 vaccine compared to those that received the IB-H120 vaccine. In conclusion, the homologous IB-H120-D274 vaccine showed superior results compared to the IB-H120 vaccine.

The real-world effectiveness of fluvoxamine therapy in mild to moderate COVID-19 patients; A historical cohort study (Fluvoxa Trial)

BackgroundFluvoxamine (FVX) has been proposed as a potential treatment for severe COVID-19 by the σ-1 receptor agonist, which can reduce cytokine production. However, the efficacy of FVX remains controversial. MethodsA historical retrospective cohort study was conducted in mild to moderate COVID-19 patients, 2:1 ratio of standard of care (SOC) and FVX treatments to assess the effectiveness of FVX in preventing deterioration by the fifth day of treatment. ResultsOf 752 eligible patients, 234 received FVX while 518 received SOC, and there was no significant difference in the effectiveness of FVX and SOC in preventing clinical deterioration. On the fifth day after treatment, 86.1 % of patients in the FVX-treated group did not experience clinical deterioration compared to 78.7 % in the SOC group. Notably, the FVX group had higher rates of pneumonia development and hospitalization, requiring more oxygen supplementation while showing less reduction in viral shedding than the SOC group. However, no difference in mechanical ventilation use, ICU admission, and survival was observed. ConclusionFluvoxamine treatment is failed to demonstrate effectiveness in preventing deterioration in mild to moderate COVID-19 and may lead to a higher incidence of pneumonia, hospitalization, and oxygen supplementation, necessitating careful consideration before prescribing the drug for COVID-19.

Study of Cellular and Humoral Immunity and Histopathology of Target Tissues Following Newcastle Clone12IR Vaccine Administration in SPF Chickens.

Newcastle disease (ND) is a highly contagious viral infection affecting poultry production in many countries. Strict biosecurity and the administration of live attenuated vaccines against the ND virus (NDV) are the main implements of controlling programs. This study evaluated the efficacy and potency of the Razi Clone12IR Newcastle vaccine in specific pathogen-free (SPF) chickens. Chickens were vaccinated with either the Razi Clone12IR vaccine (group A1, n=20) or an imported Clone vaccine (B1, n=20) in the first week of life and boosted in the second week via eye drop, while negative control chickens received PBS (C1, n=20). Half of the birds in each group were challenged with the virulent NDV strain in the third post-vaccination week (A2, B2, and C2 groups). Specific antibody responses were determined in the collected sera by the hemagglutination inhibition (HI) assay for up to eight weeks. Cell-mediated immunity (CMI) was determined by the lymphocyte proliferation assay three and six weeks after the second vaccination. Sections of the tissues and organs, including the trachea, lungs, cecal tonsils, spleen, the bursa of Fabricius, liver, and small intestine, were subjected to histopathology. The immunized groups A1 and B1 showed significantly higher HI antibody titers before the challenge than the control group. In addition, lymphocyte proliferation responses significantly increased in the peripheral blood of the vaccinated groups. After the challenge, the A2 and B2 groups conferred good protection and drastically reduced virus shedding. No main lesions were noted in the tissues or organs of the vaccinated group in histopathology. In a few cases, mild microscopic lesions were observed, including the infiltration of inflammatory cells, which was related to the effect of the vaccine virus. These results indicate that the Razi Clone12IR vaccine is safe and can be an efficient tool for NDV infections by inducing protective humoral and CMI responses.

Intranasal administration with recombinant vaccine PRVXJ-delgE/gI/TK-S induces strong intestinal mucosal immune responses against PDCoV

Porcine deltacoronavirus (PDCoV) is a novel coronavirus that causes enteric diseases in pigs leading to substantial financial losses within the industry. The absence of commercial vaccines and limited research on PDCoV vaccines presents significant challenges. Therefore, we evaluated the safety and immunogenicity of recombinant pseudorabies virus (PRV) rPRVXJ-delgE/gI/TK-S through intranasal mucosal immunization in weaned piglets and SPF mice. Results indicated that rPRVXJ-delgE/gI/TK-S safely induced PDCoV S-specific and PRV gB-specific antibodies in piglets, with levels increasing 7 days after immunization. Virus challenge tests demonstrated that rPRVXJ-delgE/gI/TK-S effectively improved piglet survival rates, reduced virus shedding, and alleviated clinical symptoms and pathological damage. Notably, the recombinant virus reduced anti-inflammatory and pro-inflammatory responses by regulating IFN-γ, TNF-α, and IL-1β secretion after infection. Additionally, rPRVXJ-delgE/gI/TK-S colonized target intestinal segments infected with PDCoV, stimulated the secretion of cytokines by MLVS in mice, stimulated sIgA secretion in different intestinal segments of mice, and improved mucosal immune function. HE and AB/PAS staining confirmed a more complete intestinal mucosal barrier and a significant increase in goblet cell numbers after immunization. In conclusion, rPRVXJ-delgE/gI/TK-S exhibits good immunogenicity and safety in mice and piglets, making it a promising candidate vaccine for PDCoV.

Evaluation of inactivated avian influenza virus and Newcastle disease virus bivalent vaccination program against newly circulated H5N8 and NDV strains

Avian influenza virus (AIV) and Newcastle disease virus (NDV) are respiratory illness syndromes that have recently been detected in vaccinated flocks and are causing major financial losses in the chicken farming industry. The objective was to evaluate the efficacy of Valley Vac H5Plus NDVg7 vaccine in protecting chickens against the H5N8 and NDV strains that have recently been circulating in comparison with the efficacy of the commercially available bivalent H5+ND7 vaccine. In contrast to the H5+ND7 vaccine, which was made of genetically distinct H5N8/2018 clade 2.3.4.4b genotype group (G5), H9N2/2016, H5N1/2017, and genetically comparable NDV genotype VII 1.1/2019 of the recently circulating challenge viruses, the Valley Vac H5Plus NDVg7 vaccine consisted of the recently isolated (RG HPAI H5N1 AIV/2015 Clade 2.2.1.2, RG HPAIV H5N8/2020 Clade 2.3.4.4b genotype group 6 (G6), and NDV genotype VII 1.1/2012) which were genetically similar to challenged strains. To determine the effectiveness of the Valley Vac H5Plus NDVg7 vaccine, a total of 70-day-old commercial chicks were divided into 7 groups of 10 birds each. Groups (G1 and G4) received Valley Vac H5Plus NDVg7 vaccine. Groups (G2 and G5) groups received commercial H5+ND7 vaccine. While groups (G3 and G6) were kept nonvaccinated, and group (G7) was kept as a nonchallenged and nonvaccinated. After 3-wk post vaccination (WPV), groups G1, G2, and G3 were challenged with A/Duck/ Egypt/SMG4/2019(H5N8) genotype G6. On the other hand, groups G4, G5, G6 were challenged with NDV/EGYPT/18629F/2018 genotype VII 1.1 with an intranasal injection of 0.1 mL. Antibody titer was calculated at the first 3 wk after vaccination, and the viral shedding titer was calculated at 3-, 5-, and 7-days post challenge. Mortality and morbidity rates were monitored daily during the experiment, and for the first 10 d after the challenge, to provide an estimate of the protection rate. The results showed that a single dosage of 0.5 mL per bird of Valley Vac H5Plus NDVg7 vaccine provides 80% protection against both H5N8 and NDV, compared to the bivalent H5+ND7 vaccine, which provided 20 and 80% protection against H5N8 and NDV, respectively. In addition, 0.5 mL per bird of Valley Vac H5Plus NDVg7 vaccine produced a greater immune response against both viruses than commercial vaccination at 1 to 3 WPV with a significant difference at 1 WPV for H5N8 and a comparatively higher immune response for NDV. Furthermore, it reduced virus shedding of H5N8 on the third, fifth, seventh, and tenth days lower than H5+ND7 vaccine with a significant difference on the third day for H5N8 and relatively lower than bivalent H5+ND7 vaccine for NDV with a significant difference on the fifth day. The Valley vaccinated group demonstrated more tissue intactness compared to the commercially vaccinated group against the H5N8 challenge, however the bivalent commercially vaccinated group showed the similar level of tissue integrity against NDV. In conclusion, Valley Vac H5Plus NDVg7 that contains the genetically similar strain to recently circulating challenged virus (H5N8 genotype G6) provided better protection with greater immune response and decreased the amount of virus shed against H5N8 genotype G6 and showed less histopathological alteration than the commercial bivalent H5+ND7 vaccine that contain genetically distinct (H5N8 genotype G5). However the Valley Vac H5Plus NDVg7 provided the same protection with relatively high immune response and relatively decreased the amount of virus shed and showed equal tissue integrity than the commercial bivalent H5+ND7 vaccine against NDV genotype VII 1.1 that contain the same genotype of NDV genotype VII 1.1.

Influenza H3 hemagglutinin vaccine with scrambled immunodominant epitopes elicits antibodies directed toward immunosubdominant head epitopes.

Vaccination is the most effective countermeasure to reduce the severity of influenza. Current seasonal influenza vaccines mainly elicit humoral immunity targeting hemagglutinin (HA). In particular, the amino acid residues around the receptor-binding site in the HA head domain are predominantly targeted by humoral immunity as "immunodominant" epitopes. However, mutations readily accumulate in the head domain due to high plasticity, resulting in antigenic drift and vaccine mismatch, particularly with influenza A (H3N2) viruses. A vaccine strategy that targets more conserved immunosubdominant epitopes is required to attain a universal vaccine. Here, we designed an H3 HA vaccine antigen with various amino acids at immunodominant epitopes of the HA head domain, termed scrambled HA (scrHA). In ferrets, scrHA vaccination induced lower serum neutralizing antibody levels against homologous virus compared with wild-type (WT) HA vaccination; however, similar levels of moderately neutralizing titers against antigenically distinct H3N2 viruses were observed. Ferrets vaccinated with scrHA twice and then challenged with homologous or heterologous virus showed the same level of reduced virus shedding in nasal swabs as WT HA-vaccinated animals but reduced body temperature increase, whereas WT HA-vaccinated ferrets exhibited body temperature increases similar to those of mock-vaccinated animals. scrHA elicited antibodies against HA immunodominant and -subdominant epitopes at lower and higher levels, respectively, than WT HA vaccination, whereas antistalk antibodies were induced at the same level for both groups, suggesting scrHA-induced redirection from immunodominant to immunosubdominant head epitopes. scrHA vaccination thus induced broader coverage than WT HA vaccination by diluting out the immunodominancy of HA head epitopes. IMPORTANCE Current influenza vaccines mainly elicit antibodies that target the immunodominant head domain, where strain-specific mutations rapidly accumulate, resulting in frequent antigenic drift and vaccine mismatch. Targeting conserved immunosubdominant epitopes is essential to attain a universal vaccine. Our findings with the scrHA developed in this study suggest that designing vaccine antigens that "dilute out" the immunodominancy of the head epitopes may be an effective strategy to induce conserved immunosubdominant epitope-based immune responses.

Study of Cellular and Humoral Immunity and Histopathology of Target Tissues Following Newcastle Clone12IR Vaccine Administration in SPF Chickens

Newcastle disease (ND) is a highly contagious viral infection affecting poultry production in many countries. Strict biosecurity and the administration of live attenuated vaccines against the ND virus (NDV) are the main implements of controlling programs. This study evaluated the efficacy and potency of the Razi Clone12IR Newcastle vaccine in specific pathogen-free (SPF) chickens. Chickens were vaccinated with either the Razi Clone12IR vaccine (group A1, n=20) or an imported Clone vaccine (B1, n=20) in the first week of life and boosted in the second week via eye drop, while negative control chickens received PBS (C1, n=20). Half of the birds in each group were challenged with the virulent NDV strain in the third post-vaccination week (A2, B2, and C2 groups). Specific antibody responses were determined in the collected sera by the hemagglutination inhibition (HI) assay for up to eight weeks. Cell-mediated immunity (CMI) was determined by the lymphocyte proliferation assay three and six weeks after the second vaccination. Sections of the tissues and organs, including the trachea, lungs, cecal tonsils, spleen, the bursa of Fabricius, liver, and small intestine, were subjected to histopathology. The immunized groups A1 and B1 showed significantly higher HI antibody titers before the challenge than the control group. In addition, lymphocyte proliferation responses significantly increased in the peripheral blood of the vaccinated groups. After the challenge, the A2 and B2 groups conferred good protection and drastically reduced virus shedding. No main lesions were noted in the tissues or organs of the vaccinated group in histopathology. In a few cases, mild microscopic lesions were observed, including the infiltration of inflammatory cells, which was related to the effect of the vaccine virus. These results indicate that the Razi Clone12IR vaccine is safe and can be an efficient tool for NDV infections by inducing protective humoral and CMI responses.

Antiviral treatment with valacyclovir reduces virus shedding in saliva of Antarctic expeditioners

IntroductionReactivation of herpes viruses, such as Epstein–Barr virus (EBV), herpes simplex virus 1 (HSV1), and varicella zoster virus (VZV), increases in astronauts during spaceflight, compared with their preflight and postflight levels. Reactivations can increase the risk of associated clinical conditions, such as herpes zoster, chronic neuropathic pain, vision loss, stroke, cognitive impairment, and cold sores. Furthermore, continued viral shedding for longer periods after space travel may increase the risk of viral transmission to uninfected crew contacts, including, but not limited to, the immunocompromised and newborn infants. Thus, it is essential to develop spaceflight countermeasures to prevent herpes viral reactivations to ensure the health of crewmembers and their contacts. One such countermeasure is the prophylactic administration of an antiviral drug (valacyclovir) against the alpha herpesviruses (VZV and HSV1). To determine the effectiveness of this countermeasure, we studied the shedding of EBV, VZV, and HSV1 in Antarctic expeditioners, who have similar salivary viral shedding patterns during winter-over to astronauts during long spaceflights.MethodsThe efficacy of this antiviral drug as a countermeasure was determined using three major parameters in the saliva of expeditioners during winter-over with and without administration of this drug: (i) viral load and frequency, (ii) physiological stress biomarkers [i.e., levels of cortisol, dehydroepiandrosterone (DHEA), and amylase), and (iii) immune markers (i.e., inflammatory cytokines)]. Thirty-two volunteers from two Antarctic stations (McMurdo and South Pole) participated in this study. Participants were randomly assigned to either the treatment group (valacyclovir HCl: 1 g/day) or placebo group (oyster calcium: 500mg/day). ResultsViral shedding of EBV reduced significantly (&amp;gt; 24-fold) in the treatment group compared with the placebo group. HSV1 was also reduced by more than fivefold, but this was not statistically significant. No VZV shedding was observed in any of the participants. In the placebo group 50% of the saliva samples had measurable viral DNA (EBV, HSV1, or both), compared with 19% of the treatment group. There was no significant change in the ratio of cortisol to DHEA or levels of alpha-amylase, indicating that physiological stress was similar between the groups. No difference was detected in levels of salivary cytokines, except IL-10, which was found in significantly lower levels in the treatment group. DiscussionThese data indicate that valacyclovir is a safe and successful intervention to reduce EBV and HSV1 shedding in individuals subjected to extreme environments and stressors.

A Booster with a Genotype-Matched Inactivated Newcastle Disease Virus (NDV) Vaccine Candidate Provides Better Protection against a Virulent Genotype XIII.2 Virus.

Newcastle disease (ND) is endemic in Bangladesh. Locally produced or imported live Newcastle disease virus (NDV) vaccines based on lentogenic virus strains, locally produced live vaccines of the mesogenic Mukteswar strain, as well as imported inactivated vaccines of lentogenic strains, are being used in Bangladesh under different vaccination regimens. Despite these vaccinations, frequent outbreaks of ND are being reported in Bangladesh. Here we compared the efficacy of booster immunization with three different vaccines in chickens that had been primed with two doses of live LaSota vaccine. A total of 30 birds (Group A) were primed with two doses of live LaSota virus (genotype II) vaccine at days 7 and 28, while 20 birds (Group B) remained unvaccinated. At day 60, birds of Group A were divided into three sub-groups, which received booster immunizations with three different vaccines; A1: live LaSota vaccine, A2: inactivated LaSota vaccine, and A3: inactivated genotype XIII.2 vaccine (BD-C161/2010 strain from Bangladesh). Two weeks after booster vaccination (at day 74), all vaccinated birds (A1-A3) and half of the unvaccinated birds (B1) were challenged with a genotype XIII.2 virulent NDV (BD-C161/2010). A moderate antibody response was observed after the primary vaccination, which substantially increased after the booster vaccination in all groups. The mean HI titers induced by the inactivated LaSota vaccine (8.0 log2/5.0 log2 with LaSota/BD-C161/2010 HI antigen) and the inactivated BD-C161/2010 vaccine (6.7 log2/6.2 log2 with LaSota/BD-C161/2010 HI antigen) were significantly higher than those induced by the LaSota live booster vaccine (3.6 log2/2.6 log2 with LaSota/BD-C161/2010 HI antigen). Despite the differences in the antibody titers, all chickens (A1-A3) survived the virulent NDV challenge, while all the unvaccinated challenged birds died. Among the vaccinated groups, however, 50% of the chickens in Group A1 (live LaSota booster immunization) shed virus at 5- and 7-days post challenge (dpc), while 20% and 10% of the chickens in Group A2 (inactivated LaSota booster immunization) shed virus at 3 and 5 dpc, respectively, and only one chicken (10%) in Group A3 shed virus at 5 dpc. In conclusion, the genotype-matched inactivated NDV booster vaccine offers complete clinical protection and a significant reduction in virus shedding.

The protection conferred against virulent Newcastle disease virus (vNDV) genotype VII by commercial double recombinant HVT vaccines and NDV live-attenuated vaccine as prime/boost vaccination regimens in commercial broiler chickens carrying maternally-derived antibodies (MDAs) against NDV

ABSTRACT Vaccines against vNDV are readily available and potentially protective; nevertheless, improved vaccination protocols are required to prevent clinical disease and discontinue the spread of the virus. This study assessed the effectiveness of two commercial recombinant herpesvirus of turkey vector vaccines (rHVT-NDV-IBDV) that express the fusion (F) protein of NDV and the virus protein 2 (VP2) of infectious bursal disease virus (IBDV). In commercial broilers with maternally-derived antibodies (MDAs) the efficacy of the rHVT-NDV-IBDV vaccines was evaluated when administered alone, in combination with live-attenuated NDV vaccine at one-day-old, or as part of a prime/boost strategy. The vaccinated birds were challenged with the genotype VIId vNDV strain (NDV/chicken/Egypt/1/2015) at various ages (14, 24 and 35 days). In comparison to sham-vaccinated control birds, the applied vaccination regimens were able to reduce or prevent mortality and virus shedding and clinical disease. Two weeks post-application, the two vector vaccines were serologically reactive with the MDAs and induced protective immune responses against the F protein. In the instance of early challenge at 14 days old, the combination of recombinant rHVT-NDV-IBDV with a live vaccine offered better protection and reduced virus shedding compared to the vector vaccine alone. Boosting with live NDV vaccine at 14 days old increased the protective effect of the vector vaccines and reduced virus shedding and the clinical index after challenge at 24 days old. Both combining and/or boosting with live vaccine together with the vector vaccine provided better protection and minimized virus shedding compared with vaccination with vector vaccine only in the instance of 5-week-old challenge.