Serum Antibody Titers Research Articles

Development of an Injectable DNA Vaccine Against Aeromonas hydrophila Infection Nanoencapsulated With Poly(Lactic‐Co‐Glycolic) Acid (PLGA) in Common Carp

In this study, we developed an injectable DNA vaccine targeting the aopB gene of Aeromonas hydrophila, encapsulated within poly(lactic‐co‐glycolic acid) (PLGA) nanoparticles, for use in common carp. Juvenile common carp were divided into six groups with three replicates each. Groups A and B received intramuscular injections of the plasmid containing the target gene (pCDNA3.1‐aopB) with or without encapsulation, respectively. Groups C and D received the plasmid lacking the target gene via the same route. Group E received PLGA, while Group F (control) received phosphate‐buffered saline. Sampling occurred on days 0, 30, and 60, and hematological and immunological indices were compared among the groups. On day 60, all groups were challenged with Aeromonas hydrophila, and cumulative mortality rates were assessed. Our results indicated successful detection of the target gene in various tissues of vaccinated fish. Notably, vaccinated groups exhibited a significant decrease in cumulative mortality (p < 0.05). Immunological indices, such as serum antibody titer and nonspecific immune responses, significantly improved in vaccinated groups, particularly those receiving the DNA vaccine with PLGA encapsulation (p < 0.05). Overall, the DNA vaccine, especially when nanoencapsulated with PLGA, demonstrated efficacy and immunogenicity against A. Hydrophila in common carp, suggesting its potential as a vaccination strategy against this infection. Further research could optimize its effectiveness and applicability.

Serum AZD7442 (tixagevimab-cilgavimab) concentrations and in vitroIC50 values predict SARS-CoV-2 neutralising antibody titres.

The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) necessitates rapid methods for assessing monoclonal antibody (mAb) potency against emerging variants. Authentic virus neutralisation assays are considered the gold standard for measuring virus-neutralising antibody (nAb) titres in serum. However, authentic virus-based assays pose inherent practical challenges for measuring nAb titres against emerging SARS-CoV-2 variants (e.g. storing infectious viruses and testing at biosafety level-3 facilities). Here, we demonstrate the utility of pseudovirus neutralisation assay data in conjunction with serum mAb concentrations to robustly predict nAb titres in serum. SARS-CoV-2 nAb titres were determined via authentic- and lentiviral pseudovirus-based neutralisation assays using serological data from three AZD7442 (tixagevimab-cilgavimab) studies: PROVENT (NCT04625725), TACKLE (NCT04723394) and a phase 1 dose-ranging study (NCT04507256). AZD7442 serum concentrations were assessed using immunocapture. Serum-based half-maximal inhibitory concentration (IC50) values were derived from pseudovirus nAb titres and serum mAb concentrations, and compared with in vitro IC50 measurements. nAb titres measured via authentic- and lentiviral pseudovirus-based neutralisation assays were strongly correlated for the ancestral SARS-CoV-2 virus and SARS-CoV-2 Alpha. Serum AZD7442 concentrations and pseudovirus nAb titres were strongly correlated for multiple SARS-CoV-2 variants with all Spearman correlation coefficients ≥ 0.78. Serum-based IC50 values were similar to in vitro IC50 values for AZD7442, for ancestral SARS-CoV-2 and Alpha, Delta, Omicron BA.2 and Omicron BA.4/5 variants. These data highlight that serum mAb concentrations and pseudovirus in vitro IC50 values can be used to rapidly predict nAb titres in serum for emerging and historical SARS-CoV-2 variants.

Brucellosis outbreak in a remote village in northwestern Tajikistan in 2023: a matched case-control study.

A sharp increase in reported brucellosis incidence was observed in northwestern Tajikistan (from 1.0/100,000 people in January-May 2022 to 32.7/100,000 in January-May 2023). Most (82%) cases were from the same remote mountainous village (population = 10,712). The aim of this study was to identify risk factors for brucellosis infection and mitigate disease risk. Using a case-control design, we conducted face-to-face interviews and collected blood samples during May-June 2023. Fifty-seven cases and 114 controls were recruited. Cases were the first person in a household diagnosed with brucellosis during February-June 2023 with positive serum agglutination test and antibody titers ≥1/160 from blood samples. Two controls were selected for each case (neighbors from different households matched by age and sex). Controls testing positive were excluded and replaced. We conducted conditional multivariable logistic regression to calculate adjusted odds ratio (AOR) and 95% confidence intervals (CI). Among the 87 brucellosis patients reported, 57 (66%) agreed to participate and didn't have secondary cases in the household. Of the 57 cases, 68% were 15-44 years old, and 44% were male. Cases peaked in May 2023. Common symptoms were joint pain (95%), fever (84%), weakness (72%), and night sweats (65%). Of selected controls, 13% tested positive and were excluded. All cases and 94% of controls owned livestock (mostly cattle, sheep, or goats); no animals had not been vaccinated in the past 5 years. Brucellosis was associated with consumption of both homemade kaymak (clotted cream) and home-raised meat compared with neither (AOR: 59 [95%CI: 4.3-798], p < 0.01), home-raised meat but not kaymak compared with neither (AOR: 54 [4.0-731], p < 0.01), and involvement in animal slaughter compared with no involvement (AOR: 36 [2.8-461], p < 0.01). Contact with unvaccinated livestock or consumption of their products was a key contributor to this outbreak in a remote village of Tajikistan. With 13% of controls testing positive, true incidence was likely greater than reported. Following our investigation, a brucellosis awareness education campaign and animal vaccination campaigns were carried out in the region and only one case was reported in September 2023.

A scalable synthesis of adjuvanting antigen depots based on metal-organic frameworks.

Vaccines have saved countless lives by preventing and even irradicating infectious diseases. Commonly used subunit vaccines comprising one or multiple recombinant proteins isolated from a pathogen demonstrate a better safety profile than live or attenuated vaccines. However, the immunogenicity of these vaccines is weak, and therefore, subunit vaccines require a series of doses to achieve sufficient immunity against the pathogen. Here, we show that the biomimetic mineralization of the inert model antigen, ovalbumin (OVA), in zeolitic imidazolate framework-8 (ZIF-8) significantly improves the humoral immune response over three bolus doses of OVA (OVA 3×). Encapsulation of OVA in ZIF-8 (OVA@ZIF) demonstrated higher serum antibody titers against OVA than OVA 3×. OVA@ZIF vaccinated mice displayed higher populations of germinal center (GC) B cells and IgG1+ GC B cells as opposed to OVA 3×, indicative of class-switching recombination. We show that the mechanism of this phenomenon is at least partly owed to the metalloimmunological effects of the zinc metal as well as the sustained release of OVA from the ZIF-8 composite. The system acts as an antigen reservoir for antigen-presenting cells to traffic into the draining lymph node, enhancing the humoral response. Lastly, our model system OVA@ZIF is produced quickly at the gram scale in a laboratory setting, sufficient for up to 20 000 vaccine doses.

MRNA lipid nanoparticles expressing cell-surface cleavage independent HIV Env trimers elicit autologous tier-2 neutralizing antibodies.

The HIV-1 envelope glycoprotein (Env) is the sole neutralizing determinant on the surface of the virus. The Env gp120 and gp41 subunits mediate receptor binding and membrane fusion and are generated from the gp160 precursor by cellular furins. This cleavage event is required for viral entry. One approach to generate HIV-1 neutralizing antibodies following immunization is to express membrane-bound Env anchored on the cell-surface by genetic means using the natural HIV gp41 transmembrane (TM) spanning domain. To simplify the process of Env trimer membrane expression we sought to remove the need for Env precursor cleavage while maintaining native-like conformation following genetic expression. To accomplish these objectives, we selected our previously developed 'native flexibly linked' (NFL) stabilized soluble trimers that are both near-native in conformation and cleavage-independent. We genetically fused the NFL construct to the HIV TM domain by using a short linker or by restoring the native membrane external proximal region, absent in soluble trimers, to express the full HIV Env ectodomain on the plasma membrane. Both forms of cell-surface NFL trimers, without and with the MPER, displayed favorable antigenic profiles by flow cytometry when expressed from plasmid DNA or mRNA. These results were consistent with the presence of well-ordered cell surface native-like trimeric Env, a necessary requirement to generate neutralizing antibodies by vaccination. Inoculation of rabbits with mRNA lipid nanoparticles (LNP) expressing membrane-bound stabilized HIV Env NFL trimers generated tier 2 neutralizing antibody serum titers in immunized animals. Multiple inoculations of mRNA LNPs generated similar neutralizing antibody titers compared to immunizations of matched NFL soluble proteins in adjuvant. Given the recent success of mRNA vaccines to prevent severe COVID, these are important developments for genetic expression of native-like HIV Env trimers in animals and potentially in humans.

Assessment of Serum Antibody Titers in Cows and Buffalos Post-Septicaemia Epizootica Outbreak in Aceh Singkil District, Indonesia

Abstract. The control of Septicaemia epizootica (SE) through a vaccination program has been implemented, but fatal cases are still frequently reported in Indonesia. This study aims to measure the antibody titers of bovines in the area affected by SE outbreaks and assess the coverage of ongoing vaccinations. We collected 117 serum samples from bovines and buffalos in Gunung Meriah District (54 samples), Singkohor (9 samples), Singkil (9 samples), and Singkil Utara (45 samples) in the Aceh Singkil area, using a simple random sampling method to select the sub-districts. We examined serum samples using the Enzyme-Linked Immunosorbent Assay (ELISA) considered antibody titers against SE seropositive if they were above 77 ELISA Units (EU). The vaccination coverage of sampled cattle was only 22.22%, and the percentage of cattle/buffalo with seropositive SE titers (&gt;77 EU) in the four sub-districts of Aceh Singkil was 29.06%.

Long-term Follow-up of a Phase 1/2a Clinical Trial of a Stem Cell-Derived Bioengineered Retinal Pigment Epithelium Implant for Geographic Atrophy

PurposeTo report long-term results from a Phase 1/2a clinical trial assessment of a scaffold-based human embryonic stem cell-derived retinal pigmented epithelium (RPE) implant in subjects with advanced geographic atrophy (GA). DesignThe study was a US Food and Drug Administration (FDA)-approved single-arm, open-label Phase 1/2a clinical trial. SubjectsSubjects were between the ages of 69 and 85 at the time of enrollment and were legally blind in the treated eye (best corrected visual acuity (BCVA) of ≤ 20/200) as a result of GA involving the fovea. InterventionThe clinical trial enrolled 16 subjects, 15 of whom were successfully implanted. The implant was administered to the worse-seeing eye with the use of a custom subretinal insertion device. The companion non-implanted eye served as the control. The primary endpoint was at 1 year; thereafter subjects were followed at least yearly. Main Outcome MeasuresSafety was the primary endpoint of the study. The occurrence and frequency of adverse events were determined by scheduled eye exams, including measurement of BCVA, intraocular pressure, and multimodal imaging (fundus photography, optical coherence tomography, and fluorescein angiography). In addition, serum antibody titers were collected to monitor systemic humoral immune responses to the implant cells. ResultsAt a median follow-up of three years, fundus photography revealed no migration of the implant. There were no unanticipated, severe, implant-related adverse events throughout the follow-up period, and the most common anticipated severe adverse event (severe retinal hemorrhage) was eliminated in the second cohort (9 subjects) through the use of improved intraoperative hemostasis. Non-severe, transient retinal hemorrhages were noted either intra-op or post-op in all subjects as anticipated for a subretinal surgical procedure. Throughout the median 3-year follow-up, the results show that implanted eyes were more likely to improve by >5 letters BCVA, and less likely to decrease by >5 letters compared to non-implanted eyes. ConclusionsThis report details the long-term follow-up of the largest study of subjects with GA to receive a scaffold-based stem cell-derived bioengineered RPE implant. Results show that the implant, at a median 3-year follow-up, is safe and well-tolerated in subjects with advanced dry AMD. The safety profile, along with the early indication of efficacy, warrants further clinical evaluation of this novel approach for the treatment of GA.

Antibody Response Following the Intranasal Administration of SARS-CoV-2 Spike Protein-CpG Oligonucleotide Vaccine.

The new coronavirus infection causes severe respiratory failure following respiratory tract infection with severe acute respiratory syndrome-related coronavirus (SARS-CoV-2). All currently approved vaccines are administered intramuscularly; however, intranasal administration enhances mucosal immunity, facilitating the production of a less invasive vaccine with fewer adverse events. Herein, a recombinant vaccine combining the SARS-CoV-2 spike protein receptor-binding domain (RBD), or S1 protein, with CpG-deoxyoligonucleotide (ODN) or aluminum hydroxide (alum) adjuvants was administered intranasally or subcutaneously to mice. Serum-specific IgG titers, IgA titers in the alveolar lavage fluid, and neutralizing antibody titers were analyzed. The nasal administration of RBD protein did not increase serum IgG or IgA titers in the alveolar lavage fluid. However, a significant increase in serum IgG was observed in the intranasal group administered with S1 protein with CpG-ODN and the subcutaneous group administered with S1 protein with alum. The IgA and IgG levels increased significantly in the alveolar lavage fluid only after the intranasal administration of the S1 protein with CpG-ODN. The neutralizing antibody titers in serum and bronchoalveolar lavage were significantly higher in the intranasal S1-CpG group than in every other group. Hence, the nasal administration of the S1 protein vaccine with CpG adjuvant might represent an effective vaccine candidate.

Response of broiler breeder pullets when fed hydrolyzed whole yeast from placement to 22 wk of age

The study examined the effects of feeding broiler breeder pullets hydrolyzed whole yeast (HY) from hatch to 22 wk of age (WOA). A total of 524-day-old Ross 708 pullets were placed in floor pens (∼24 birds/pen) for the starter (0-4 WOA) and grower (5-18 WOA) phases, then transferred to the egg production facility and redistributed to ∼20 birds/pen for the prelay phase (19-22 WOA). Two diets were allocated to pens (0-18 WOA; n = 11) and (19-22 WOA; n-12). The diets were a control corn and soybean meal diet formulated to meet specifications and control plus 0.05% HY (HY). Birds had ad libitum access to feed in the first week and daily feed allocation based on pen BW from 2 WOA. Birds had free access to water throughout the trial. Body weight (BW) and uniformity (BW CV) were monitored. Boosters for infectious bronchitis and New Castle disease vaccines were administered at 18 WOA, and samples of pullets bled for antibody titer 5-day later. One pullet/pen was randomly selected, weighed, bled for plasma biochemistry, and necropsied for organ weights, ceca digesta for short-chain fatty acids (SCFA), and leg bones morphometry. In the starter and grower phases, birds fed HY were lighter and gained less (P < 0.05) than control birds. However, there were no diet effects (P > 0.05) on growth, the BW prelay phase, or BW uniformity throughout the trial. There were no (P > 0.05) diet effects on breast, gastrointestinal, liver and bursa weights, serum antibody titers, plasma biochemistry, SCFA and bone attributes. However, pullets fed HY had heavier (P = 0.047) spleen and tended to have lower (P = 0.080) plasma concentrations of aspartate aminotransferase (AST) relative to control pullets. In conclusion, the parameters assessed showed no negative consequences of feeding HY to broiler breeder pullets. However, effects on the spleen and plasma AST may indicate modest modulation of immunity and metabolism. The impact of the provision of HY during broiler breeder pullet phase on reproductive performance and chick quality should be investigated.

SARS-CoV-2 mucosal vaccine protects against clinical disease with sex bias in efficacy

Intranasal mucosal vaccines can more effectively induce mucosal immune responses against SARS-CoV-2. Here, we show in hamsters that an intranasal subunit mucosal vaccine boost with the beta variant S1 can prevent weight loss, in addition to reducing viral load, which cannot be studied in macaques that don’t develop COVID-like disease. Protective efficacy against both viral load and weight loss correlated with serum antibody titers. A sex bias was detected in that immune responses and protection against viral load were greater in females than males. We also found that priming with S1 from the Wuhan strain elicited lower humoral immune responses against beta variant and led to less protection against beta viral challenge, suggesting the importance of matched antigens. The greater efficacy of mucosal vaccines in the upper respiratory tract and the need to consider sex differences in vaccine protection are important in the development of future improved COVID-19 vaccines.

Comparative Immunogenicity of the Gam-COVID-Vac Vaccine under Intranasal and Intramuscular Administration

In this work, we set out to compare the immunogenicity of the Gam-COVID-Vac two-component vaccine produced by GENERIUM JSC (Russia) following its intranasal or intramuscular administration of the first or both components to BALB/c mice. The immunogenicity was evaluated according to antigen-specific IgG and IgA antibodies in the blood and bronchoalveolar fluid, the number of antigen-specific IFN-γ-producing T-lymphocytes, the number of antigen-specific IFN-γ-producing CD4 and CD8 T-lymphocytes. Intranasal administration was shown to induce the mucosal immunity, significantly exceeding both qualitatively and quantitatively the effect of intramuscular administration (by the number of animals with antigen-specific IgA antibodies and the titer of antibodies in blood serum and bronchoalveolar lavage). At the same time, intramuscular administration slightly exceeded the effect obtained under intranasal administration in terms of the total number of CD8-IFN-γ-producing lymphocytes.

Identification of 3 neutralizing linear epitopes on the VP8 outer capsid protein of group A equine rotavirus.

To identify protective equine rotavirus group A (ERVA) VP8 epitopes and demonstrate that immunizing hens with synthetic peptides based on these epitopes would yield high-titered, neutralizing egg yolk antibodies for potential application in foals. 26 rotavirus-positive, client-owned foals were included in the study. Five white leghorn hens were used for antibody production. Chicken antibodies were raised against 3 synthetic epitope peptides from the VP8 protein of the common ERVA P-type, P4[12] using CD40-targeted streptavidin-peptide complexes. Antipeptide serum- and egg yolk antibodies were subject to ELISA and in vitro virus neutralization assays to evaluate binding and neutralization activities. Lyophilized anti-VP8 egg yolk antibodies were orally administered (30 g; q 24 h for 5 days) to foals with rotaviral diarrhea. Physical examinations were performed daily. The duration of diarrhea and any adverse effects were recorded. CD40-targeted vaccination of hens generated high titers of anti-VP8 serum and egg yolk antibodies after just 3 immunizations. These antibodies prevented in vitro infection of ERVA with titers of 128 in the serum and 94.5 in the yolk. Oral administration (30 g; q 24 h for 5 days) of lyophilized hyperimmune egg yolk to foals with rotaviral diarrhea did not reveal any adverse effects of the treatment. This study demonstrated that antibodies raised against neutralizing epitopes of the ERVA VP8 protein could prevent ERVA infection in vitro. Based on these results and previous work in other animals, in vivo evaluation of the therapeutic efficacy of anti-VP8 egg yolk antibodies is warranted.

ANTIBODY TITERS AGAINST NEWCASTLE DISEASE AND INFECTIOUS BRONCHITIS VIRUSES IN BROILER BREEDERS RAISED UNDERFLOOR VERSUS CAGE SYSTEM

The experiment was evaluated to find out the serum antibody titer of broiler breeders raised under different rearing systems (cage vs. floor) against Newcastle disease virus and infectious bronchitis disease virus. Two hundred and forty-day-old broiler breeders were equally divided into six groups Floor (V+CH), (V+Not CH) and (Not V+CH) and cage (V+CH), (V+Not CH), and (Not V+CH). Birds were vaccinated with Mukteswar, La Sota, and Massachusetts M41 in 1st week, 3rd week, and 4th week. Blood /serum samples were collected at 42 days of age. Collected data were analyzed by using a complete randomized design. The geometric mean titer (GMT) for Newcastle disease virus (NDV) of broiler breeders reared under floor versus cage housing system was measured by using the hem agglutination inhibition test and the defensive potentiality of vaccines was measured by determining the survivability rate of chickens by challenge infection. Birds vaccinated and virus-challenged showed a protective antibody titer against Newcastle disease virus in both housing systems. Significantly higher GMT was recorded for the non-vaccinated group having virus-challenged in cage female (9.76 ±0.34) and floor female (9.94 ±0.23). Protective antibody titer was calculated for broiler breeders who were regularly vaccinated. There were no significant differences (P≥0.05) observed in the cage versus floor housing system. Higher serum antibody titer in caged females (9.22±0.36) and floor (8.98±0.32) was calculated due to infection challenges. Morbidity and mortality were significantly affected by the cage and floor-rearing system. Frequencies of diseased birds and mortality were found higher on the floor compared to cages in the non-vaccinated group. Despite the regular vaccination sick female broiler breeders were found higher compared to cage broiler breeders. In the non-vaccinated group floor reared birds have a higher percentage of morbidity and mortality compared to cages. In conclusion cage and floor-rearing systems have no adverse effect on serum antibody titer and survivability of broiler breeders.

Prenatal Exposure to Poly- and Perfluoroalkyl Substances (2009-2014) and Vaccine Antibody Titers of Measles, Mumps, Rubella, and Varicella in Children Four to Eight Years Old from the Healthy Start Cohort.

Prenatal exposures to certain poly- and perfluoroalkyl substances (PFAS) are associated with reduced humoral responses to some childhood immunizations. We estimated associations between prenatal PFAS exposure and child antibody titers for measles, mumps, rubella (MMR), and varicella after immunization. We measured serum antibody titers of 145 children (4-8 y old) enrolled in the Healthy Start cohort in Colorado, whose mothers had PFAS quantified mid-pregnancy (2009-2014). We used linear and logistic regression models to assess the relationship between five PFAS detected in of mothers and continuous or non-high-censored ("low") antibody titers and quantile g-computation to evaluate the overall effect of the PFAS mixture. Median concentrations of individual PFAS were at or below the median reported among females in the United States. After receiving two vaccine doses, seropositive levels of antibodies were detected among most (93%-100%) children. Each log-unit increase in perfluorononanoate was associated with 2.09 [95% confidence interval (CI): 1.13, 3.87] times higher odds of a low measles titer, and each log-unit increase in perfluorooctanoate was associated with 2.46 (95% CI: 1.28, 4.75) times higher odds of a low mumps titer. Odds ratios for all other PFAS were elevated, but CIs included the null. Each quartile increase in the PFAS mixture was associated with 1.35 (95% CI: 0.80, 2.26) times higher odds of a low measles titer and 1.44 (95% CI: 0.78, 2.64) times higher odds of a low mumps titer. No significant associations were observed between PFAS and varicella or rubella antibodies. In stratified analyses, associations were negative among female children, except for perfluorohexane sulfonate and varicella, whereas they were positive among males. Some prenatal PFAS were associated with lower antibody titers among fully immunized children. The potential for immunotoxic effects of PFAS requires further investigation in a larger study, because exposure is ubiquitous globally. https://doi.org/10.1289/EHP12863.

SARS-CoV-2 seroprevalence determination in pets and camels in Egypt using multispecies enzyme-linked immunosorbent assay

The coronavirus disease 2019 (COVID-19) pandemic has translated into a worldwide economic recession and public health crisis. Bats have been incriminated as the main natural host for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of the COVID-19 pandemic. However, the reservoir and carrier hosts of the virus remain unknown. Therefore, a cross sectional serosurvey study was performed to estimate antibodies to SARS-CoV-2. To assess IgM antibodies to SARS-CoV-2 nucleocapsid protein (NP), a SARS-CoV-2 Double Antigen Multispecies diagnostic enzyme-linked immunosorbent assay kit was used. The seropositive samples were confirmed and validated by measuring IgG antibody titers in sera. The enrolled animals were from different locations in the Giza governorate, Egypt, and were sampled at the time of the pandemic; they comprised 92 companion animals and 92 domestic camels. The study established that 4.76% (1/21 clinical samples) of dogs, 7.69% of cats (1/13 shelter samples) and 1.08% (1/92) of camels, had measurable SARS-CoV-2 NP IgM antibodies. All IgM-seropositive samples were IgG positive with a measurable titer of 34.5, 28.6, and 25.8 UI/mL for dog, cat, and camels, respectively. According to our best knowledge, this study was the first to assess SARS-CoV-2 seroprevalence in the specific animals investigated in Egypt. These results may herald a promising epidemiological role for pet animals and camels in SARS-CoV-2 virus maintenance. Thus, our study's results ought to be confirmed with a nationwide seroprevalence study, and further studies are required to clarify whether these animals act as active or passive carriers.

Prevalence of Serum Antibody Titers against Core Vaccine Antigens in Italian Cats.

Feline core vaccines strongly recommended for all cats are against Feline panleukopenia virus (FPV), Felid herpesvirus type 1 (FeHV-1), and Feline calicivirus (FCV), but cats can be classified as low- and high-risk based on their lifestyle. The aim of this study was to determine the actual seroprotection against FPV, FeHV-1, and FCV in a large cohort of Italian cats by using the VacciCheck test. A total of 740 cats (567 owned and 173 stray cats; 435 vaccinated and 305 unvaccinated) were analyzed for Protective Antibody Titers (PATs). Differences related to origin, sex, age, breed, FIV/FeLV status, health status, and time elapsed since last vaccination were evaluated. Less than half of the entire cohort (36.4%) had PATs for all three diseases simultaneously, increasing to 48.6% if weak positive values were also considered and 50.3% when considering only the 435 vaccinated cats. Particularly, antibodies were detected against FCV, FPV, and FeHV-1 at protective titers (PATs) in 78.6%, 68.1, and 49.1% of the cats, respectively. In general, owned, neutered, and adult FIV- and/or FeLV-negative cats were the most protected categories, even if not always for the three viruses. Most cats maintained high PATs for 3 years or longer after vaccination against FPV and FCV but not FeHV-1. Long-lasting protective immunity persisted for many years after the last vaccination (more than 18 years in the oldest cats). Nevertheless, since not all cats were protected after so many years and for all pathogens, checking protection via antibody titration could be the best choice to prevent immunity breakdowns. The discussion also focuses on the reliability of antibody titration for the two URTD (upper respiratory tract disease) viruses which, unlike for FPV, is not widely accepted as a valid index of protection.

Newcastle disease vaccination program in broilers using a Apathogenic heat-resistant vaccine

The Newcastle disease (ND) is among the most common and deadly poultry diseases worldwide. Thermostable Newcastle disease virus (NDV) vaccines have been used widely to protect village chickens against Newcastle disease, due to their decreased dependence on cold chain for transport and storage. The Newcastle Disease V4 Heat-Resistant (NDV4HR) vaccine is an Apathogenic heat-resistant live vaccine that can induce immunity in chickens. A total of 60 one-day-old Arain local hybrid broilers divided into three groups of 20. Group A had the usual vaccination program in broiler flocks (7 Days old: B1 type by eye drop+ ND Killed vaccine by IM; 18 and 28 days old: Lasota strain orally), group B did not receive any vaccine, and Group C received orally the NDV4HR vaccine six times from the first day to the 35th day of rearing. All groups were nasally challenged with acute Newcastle virus (genotype VIId) on the 35th rearing day. Regarding HI serum antibody titer of the birds after the challenge, group B had the highest (7.12 ± 1.05), and Group C (6.37 ± 1.31) had a higher titer than Group A (6 ± 1.22). After the challenge with the Newcastle virus, the necropsy findings and clinical symptoms of the disease were almost similar in groups A and C. Group B showed the most signs with higher casualties than other groups. Regarding weight gain, Group C had the most weight at the end of the study (2204 ± 106). On the second day after the challenge, groups A and B had virus shedding through the trachea and cloaca; however, group B shed the virus only through the trachea. Furthermore, on the 7th day after the challenge, group A shed the virus through the cloaca, and group B through the trachea and the cloaca. At the same time, there was no virus shedding in group C. This study showed that V4HR vaccine provokes an antibody response that protects the birds against virulent virus challenge.

Immune evasion and membrane fusion of SARS-CoV-2 XBB subvariants EG.5.1 and XBB.2.3

ABSTRACT Immune evasion by SARS-CoV-2 paired with immune imprinting from monovalent mRNA vaccines has resulted in attenuated neutralizing antibody responses against Omicron subvariants. In this study, we characterized two new XBB variants rising in circulation – EG.5.1 and XBB.2.3, for their neutralization and syncytia formation. We determined the neutralizing antibody titers in sera of individuals that received a bivalent mRNA vaccine booster, BA.4/5-wave infection, or XBB.1.5-wave infection. Bivalent vaccination-induced antibodies neutralized ancestral D614G efficiently, but to a much less extent, two new EG.5.1 and XBB.2.3 variants. In fact, the enhanced neutralization escape of EG.5.1 appeared to be driven by its key defining mutation XBB.1.5-F456L. Notably, infection by BA.4/5 or XBB.1.5 afforded little, if any, neutralization against EG.5.1, XBB.2.3 and previous XBB variants – especially in unvaccinated individuals, with average neutralizing antibody titers near the limit of detection. Additionally, we investigated the infectivity, fusion activity, and processing of variant spikes for EG.5.1 and XBB.2.3 in HEK293T-ACE2 and CaLu-3 cells but found no significant differences compared to earlier XBB variants. Overall, our findings highlight the continued immune evasion of new Omicron subvariants and, more importantly, the need to reformulate mRNA vaccines to include XBB spikes for better protection.

The effect of Toll-like receptor agonists on the immunogenicity of MVA-SARS-2-S vaccine after intranasal administration in mice.

Modified Vaccinia virus Ankara (MVA) represents a promising vaccine vector for respiratory administration to induce protective lung immunity including tertiary lymphoid structure, the bronchus-associated lymphoid tissue (BALT). However, MVA expressing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike protein (MVA-SARS-2-S) required prime-boost administration to induce high titers of anti-Spike antibodies in serum and bronchoalveolar lavage (BAL). As the addition of adjuvants enables efficient tailoring of the immune responses even to live vaccines, we tested whether Toll-like receptor (TLR)-agonists affect immune responses induced by a single dose of intranasally applied MVA-SARS-2-S. We intranasally immunized C57BL/6 mice with MVA-SARS-2-S vaccine in the presence of either TLR3 agonist polyinosinic polycytidylic acid [poly(I:C)], TLR4 agonist bacterial lipopolysaccharide (LPS) from Escherichia coli, or TLR9 agonist CpG oligodeoxynucleotide (CpG ODN) 1826. At different time-points after immunization, we analyzed induced immune responses using flow cytometry, immunofluorescent microscopy, and ELISA. TLR agonists had profound effects on MVA-SARS-2-S-induced immune responses. At day 1 post intranasal application, the TLR4 agonist significantly affected MVA-induced activation of dendritic cells (DCs) within the draining bronchial lymph nodes, increasing the ratio of CD11b+CD86+ to CD103+CD86+ DCs. Nevertheless, the number of Spike-specific CD8+ T cells within the lungs at day 12 after vaccination was increased in mice that received MVA-SARS-2-S co-administered with TLR3 but not TLR4 agonists. TLR9 agonist did neither significantly affect MVA-induced DC activation nor the induction of Spike-specific CD8+ T cells but reduced both number and size of bronchus-associated lymphoid tissue. Surprisingly, the addition of all TLR agonists failed to boost the levels of Spike-specific antibodies in serum and bronchoalveolar lavage. Our study indicates a potential role of TLR-agonists as a tool to modulate immune responses to live vector vaccines. Particularly TLR3 agonists hold a promise to potentiate MVA-induced cellular immune responses. On the other hand, additional research is necessary to identify optimal combinations of agonists that could enhance MVA-induced humoral responses.

SERUM IGM AND IGG TITERS 2 WEEKS AND 8 WEEKS FROM BEGINNING OF SYMPTOMS AND THEIR RELATION TO SEVERITY IN COVID-19

BackgroundCOVID-19 pandemic, which started in late December 2019, has resulted in a significant number of morbidity and mortality worldwide. Estimating serum antibody titers of both IgM &amp; IgG against the coronavirus in patients plays a crucial role in diagnosis and assessing the severity of the infection.&#x0D; ObjectivesOur objective is to assess IgM and IgG levels at 2 and 8 weeks from the onset of COVID-19 symptoms and examine their relationship with disease severity and mortality. Additionally, we aim to determine how these antibody levels relate to patient age, BMI, gender, and any chronic illnesses they may have.&#x0D; Patients and MethodsThis prospective study was conducted at Dr. Hemn Teaching Hospital in Sulaymaniyah, from December 4th, 2021 to March 5th, 2022. It included 33 males and 28 females, aged between 17 and 92 years, all of whom were confirmed to have COVID-19 by Reverse Transcription Polymerase Chain Reaction and/or High-resolution computed tomography. Blood samples were taken 2 and 8 weeks from starting symptoms and processed by ELISA to detect IgM and IgG titers.&#x0D; ResultsMale patients accounted for 54.1%, and 63.93% were between 30-70 years of age, with 90.16% residing in the city center. The majority were non-smokers (68.85%), and 86.89% did not consume alcohol. In terms of infection severity, 22.95% had mild cases, 40.98% were moderate and 36.07% were severe-critical infections. We observed that higher antibody titers in the early phase were associated with increasing severity and mortality. A higher body mass index was identified as a risk factor for elevated antibody production while hypertension and diabetes were not.&#x0D; ConclusionOur findings suggest that higher levels of IgM and IgG antibodies during the early phase of COVID-19 are associated with increased disease severity and, consequently, higher mortality rates. Furthermore, a higher BMI was found to be a risk factor for elevated antibody production. After 8 weeks from symptoms, IgG levels remained elevated, while IgM levels declined sharply.