Serum Hemagglutination Inhibition Antibody Research Articles

Recombinant avian-derived antiviral proteins cIFITM1, cIFITM3, and cViperin as effective adjuvants in inactivated H9N2 subtype avian influenza vaccines

Vaccine adjuvants, serving as non-specific immune enhancers, play a pivotal role in the immunoprevention and control of animal diseases. This study utilized prokaryotic expression systems to express and purify chicken-derived cIFITM1, cIFITM3, and cViperin, which were then formulated as adjuvants with H9N2 avian influenza virus antigens to create inactivated vaccines. These vaccines were administered to SPF chickens to investigate their immunopotentiating functions. Additionally, the proteins were assessed for their ability to act as standalone immune enhancers. The results demonstrated that cIFITM1, cIFITM3, and cViperin significantly elevated serum hemagglutination inhibition (HI) antibody titers. Notably, when used individually, these proteins markedly enhanced the antiviral capabilities of challenged chickens, leading to alleviated clinical symptoms, reduced tracheal virus replication, diminished virus shedding, and lessened histopathological damage, with cIFITM1 exhibiting the most pronounced effect. Furthermore, the protective efficacy of two H9N2 recombinant virus inactivated vaccines supplemented with cIFITM1 adjuvant was validated, achieving a 100 % vaccine protection efficiency. In conclusion, cIFITM1, cIFITM3, and cViperin as adjuvants for influenza vaccines effectively inhibit virus replication and shedding, highlighting their significant potential in influenza prevention and control.

Immunophenotypic predictors of influenza vaccine immunogenicity in pediatric hematopoietic cell transplant recipients

AbstractPediatric hematopoietic cell transplant (HCT) recipients exhibit poor serologic responses to influenza vaccination early after transplant. To facilitate the optimization of influenza vaccination timing, we sought to identify B- and T-cell subpopulations associated with influenza vaccine immunogenicity in this population. We used mass cytometry to phenotype peripheral blood mononuclear cells collected from pediatric HCT recipients enrolled in a multicenter influenza vaccine trial comparing high- and standard-dose formulations over 3 influenza seasons (2016-2019). We fit linear regression models to estimate relationships between immune cell subpopulation numbers before vaccination and prevaccination to postvaccination geometric mean fold rises in antigen-specific (A/H3N2, A/H1N1, and B/Victoria) serum hemagglutination inhibition antibody titers (28-42 days, and ∼6 months after 2 doses). For cell subpopulations identified as predictive of a response to all 3 antigens, we conducted a sensitivity analysis including time after transplant as an additional covariate. Among 156 HCT recipients, we identified 33 distinct immune cell subpopulations; 7 significantly predicted responses to all 3 antigens 28 to 42 days after a 2-dose vaccine series, irrespective of vaccine dose. We also found evidence that baseline absolute numbers of naïve B cells, naïve CD4+ T cells, and circulating T follicular helper cells predicted peak and sustained vaccine-induced titers irrespective of dose or timing of posttransplant vaccine administration. In conclusion, several B- and T-cell subpopulations predicted influenza vaccine immunogenicity in pediatric HCT recipients. This study provides insights into the immune determinants of vaccine responses and may help guide the development of tailored vaccination strategies for this vulnerable population.

Immunogenicity of adjuvanted versus high-dose inactivated influenza vaccines in older adults: a randomized clinical trial

BackgroundAdjuvanted inactivated influenza vaccine (aIIV) and high-dose inactivated influenza vaccine (HD-IIV) are U.S.-licensed for adults aged ≥ 65 years. This study compared serum hemagglutination inhibition (HAI) antibody titers for the A(H3N2) and A(H1N1)pdm09 and B strains after trivalent aIIV3 and trivalent HD-IIV3 in an older adult population.ResultsThe immunogenicity population included 342 participants who received aIIV3 and 338 participants who received HD-IIV3. The proportion of participants that seroconverted to A(H3N2) vaccine strains after allV3 (112 participants [32.8%]) was inferior to the proportion of participants that seroconverted after HD-IIV3 (130 participants [38.5%]) at day 29 after vaccination (difference, − 5.8%; 95%CI, − 12.9% to 1.4%). There were no significant differences between the vaccine groups in percent seroconversion to A(H1N1)pdm09 or B vaccine strains, in percent seropositivity for any of the strains, or in post-vaccination GMT for the A(H1N1)pdm09 strain. The GMTs for the post-vaccination A(H3N2) and B strains were higher after HD-IIV than after aIIV3.ConclusionsOverall immune responses were similar after aIIV3 and HD-IIV3. For the primary outcome, the aIIV3 seroconversion rate for H3N2 did not meet noninferiority criteria compared with HD-IIV3, but the HD-IIV3 seroconversion rate was not statistically superior to the aIIV3 seroconversion rate.Trial registrationClinicalTrials.gov Identifier: NCT03183908.

Intranasal Single-Replication Influenza Vector Induces Cross-Reactive Serum and Mucosal Antibodies against SARS-CoV-2 Variants.

Current SARS-CoV-2 vaccines provide protection for COVID-19-associated hospitalization and death, but remain inefficient at inhibiting initial infection and transmission. Despite updated booster formulations, breakthrough infections and reinfections from emerging SARS-CoV-2 variants are common. Intranasal vaccination to elicit mucosal immunity at the site of infection can improve the performance of respiratory virus vaccines. We developed SARS-CoV-2 M2SR, a dual SARS-CoV-2 and influenza vaccine candidate, employing our live intranasal M2-deficient single replication (M2SR) influenza vector expressing the receptor binding domain (RBD) of the SARS-CoV-2 Spike protein of the prototype strain, first reported in January 2020. The intranasal vaccination of mice with this dual vaccine elicits both high serum IgG and mucosal IgA titers to RBD. Sera from inoculated mice show that vaccinated mice develop neutralizing SARS-CoV-2 antibody titers against the prototype and Delta virus strains, which are considered to be sufficient to protect against viral infection. Moreover, SARS-CoV-2 M2SR elicited cross-reactive serum and mucosal antibodies to the Omicron BA.4/BA.5 variant. The SARS-CoV-2 M2SR vaccine also maintained strong immune responses to influenza A with high titers of anti H3 serum IgG and hemagglutination inhibition (HAI) antibody titers corresponding to those seen from the control M2SR vector alone. With a proven safety record and robust immunological profile in humans that includes mucosal immunity, the M2SR influenza viral vector expressing key SARS-CoV-2 antigens could provide more efficient protection against influenza and SARS-CoV-2 variants.

Phytochemical Constituents of Propolis Flavonoid, Immunological Enhancement, and Anti-porcine Parvovirus Activities Isolated From Propolis

Propolis is widely used in health preservation and disease healing; it contains many ingredients. The previous study had revealed that the ethanolic or water extracts of propolis have a wide range of efficacy, such as antiviral, immune enhancement, anti-inflammatory, and so on, but its antiviral components and underlying mechanism of action remain unknown. In this study, we investigated the chemical composition, anti-porcine parvovirus (PPV) effectiveness, and immunological enhancement of propolis flavone ethanolic extracts. The chemical composition of propolis flavone was distinguished by ultra-performance liquid chromatography-quadrupole/time-of-flight tandem mass spectrometry analysis. In this study, the presence and characterization of 26 major components were distinguished in negative ionization modes to evaluate the effects of propolis flavonoid used as an adjuvant on the immune response of Landrace–Yorkshire hybrid sows immunized with an inactivated vaccine of PPV. Thirty Landrace-Yorkshire hybrid sows were randomly assigned to one of three groups, and the sows in the adjuvant groups were intramuscularly injected with PPV vaccine with a 2.0-ml propolis flavonoid adjuvant (PA) and oil emulsion adjuvant. After that, serum hemagglutination inhibition antibody titers and specific immunoglobulin (Ig)M and IgG subclasses were measured to evaluate the adjuvant effects of propolis flavonoid on the humoral immune responses, as well as peripheral lymphocyte proliferation activity and serum concentrations of Th1 and Th2 cytokines for cellular immunity. Results indicated an enhancing effect of PA on IgM, interleukins 2 and 4, interferon-γ, and IgG subclass responses. Especially in the effect of improving cellular immune response, the PA was the best. These findings suggested that PA can significantly enhance the immune responses against the PPV vaccine and could be an alternative way to improve PPV vaccination in sows. Furthermore, we screened the PF chemical components to the effectiveness of anti-PPV. Ferulic acid has an excellent anti-PPV effect.

MAS-1, a novel water-in-oil adjuvant/delivery system, with reduced seasonal influenza vaccine hemagglutinin dose may enhance potency, durability and cross-reactivity of antibody responses in the elderly

BackgroundIncreased influenza vaccine efficacy is needed in the elderly at high-risk for morbidity and mortality due to influenza infection. Adjuvants may allow hemagglutinin (HA) dose-sparing with enhanced immunogenicity. MAS-1 is an investigational water-in-oil emulsion-based adjuvant/delivery system comprised of stable nanoglobular aqueous droplets. MethodsA phase 1, randomized, double-blind, safety and immunogenicity, adjuvant dose escalation trial was conducted in persons aged 65 years and older. MAS-1 adjuvant dose volumes at 0.3 mL or 0.5 mL containing 9 µg per HA derived from licensed seasonal trivalent influenza vaccine (IIV, Fluzone HD 60 µg per HA, Sanofi Pasteur) were compared to high dose (HD) IIV (Fluzone HD). Safety was measured by reactogenicity, adverse events, and safety laboratory measures. Immunogenicity was assessed by serum hemagglutination inhibition (HAI) antibody titers. ResultsForty-five subjects, aged 65–83 years, were randomly assigned to receive 9 µg per HA in 0.3 mL MAS-1 (15 subjects) or HD IIV (15 subjects) followed by groups randomly assigned to receive 9 µg per HA in 0.5 mL MAS-1 (10 subjects) or HD IIV (5 subjects). Injection site tenderness, induration, and pain, and headache, myalgia, malaise and fatigue were common, resolving before day 14 post-vaccination. Clinically significant late-onset injection site reactions occurred in four of ten subjects at the 0.5 mL adjuvant dose. Safety laboratory measures were within acceptable limits. MAS-1-adjuvanted IIV enhanced mean antibody titers, mean-fold increases in antibody titer, and seroconversion rates against vaccine strains for at least 168 days post-vaccination and enhanced cross-reactive antibodies against some non-study vaccine influenza viruses. ConclusionMAS-1 adjuvant provided HA dose-sparing without safety concerns at the 0.3 mL dose, but the 0.5 mL dose caused late injection site reactions. MAS-1-adjuvanted IIV induced higher HAI antibody responses with prolonged durability including against historical strains, thereby providing greater potential vaccine efficacy in the elderly throughout an influenza season.Clinical Trial Registry: ClinicalTrials.gov # NCT02500680.

A phase 1 dose-sparing, randomized clinical trial of seasonal trivalent inactivated influenza vaccine combined with MAS-1, a novel water-in-oil adjuvant/delivery system

BackgroundNew influenza vaccines are needed to increase vaccine efficacy. Adjuvants may allow hemagglutinin (HA) dose-sparing with enhanced immunogenicity. MAS-1 is an investigational low viscosity, free-flowing, water-in-oil emulsion-based adjuvant/delivery system comprised of stable nanoglobular aqueous droplets. MethodsA phase 1, double-blind, safety and immunogenicity, HA dose escalation, randomized clinical trial was conducted. MAS-1 adjuvant with 1, 3, 5 or 9 µg per HA derived from licensed seasonal trivalent high dose inactivated influenza vaccine (IIV, Fluzone HD 60 µg per HA) in a 0.3 mL dose were compared to standard dose IIV (Fluzone SD, 15 µg per HA). Safety was measured by reactogenicity, adverse events, and clinical laboratory tests. Serum hemagglutination inhibition (HAI) antibody titers were measured for immunogenicity. ResultsSeventy-two subjects, aged 18–47 years, received one dose of either 0.3 mL adjuvanted vaccine or SD IIV intramuscularly. Common injection site and systemic reactions post-vaccination were mild tenderness, induration, pain, headache, myalgia, malaise and fatigue. All reactions resolved within 14 days post-vaccination. Safety laboratory measures were not different between groups. Geometric mean antibody titers, geometric mean fold increases in antibody titer, seroconversion rates and seroprotection rates against vaccine strains were in general higher and of longer duration (day 85 and 169 visits) with MAS-1-adjuvanted IIV at all doses of HA compared with SD IIV. Adjuvanted vaccine induced higher antibody responses against a limited number of non-study vaccine influenza B and A/H3N2 viruses including ones from subsequent years. ConclusionMAS-1 adjuvant in a 0.3 mL dose volume provided HA dose-sparing effects without safety concerns and induced higher HAI antibody and seroconversion responses through at least 6 months, demonstrating potential to provide greater vaccine efficacy throughout an influenza season in younger adults. In summary, MAS-1 may provide enhanced, more durable and broader protective immunity compared with non-adjuvanted SD IIV.Clinical Trial Registry: ClinicalTrials.gov # NCT02500680.

AddaVax Formulated with PolyI:C as a Potential Adjuvant of MDCK-based Influenza Vaccine Enhances Local, Cellular, and Antibody Protective Immune Response in Mice

Poor immune responses to inactivated influenza vaccine can be improved by effective and safe adjuvants to increase antibody titers and cellular protective response. In our study, AddaVax and PolyI:C combined adjuvant (AP adjuvant) were used for influenza vaccine development. After immunizing BALB/c mice and Wistar rats intramuscularly, Split inactivated H3N2 vaccine adjuvanted with AP elicited higher serum hemagglutination-inhibition antibodies and IgG titers. We demonstrated that AP induced a transient innate immune cytokines production at the injection site, induced H3N2 uptake by DCs, increased recruitment of monocytes and DCs in LNs, and promoted H3N2 vaccine migration; AP facilitated vaccines to induce a vigorous adaptive immune response. Besides, AP showed good safety as shown by lymph nodes (LNs) size, spleens index of BALB/c mice, and weight changes and C-reaction protein level of BALB/c mice and Wistar rats after repeated administration of high-dose vaccine with or without adjuvant. These findings indicate that AP is a potential novel adjuvant and can be used as a safe and effective adjuvant for MDCK-based influenza inactivated vaccine to induce cellular and antibody protective response.

In Vivo Production of HN Protein Increases the Protection Rates of a Minicircle DNA Vaccine against Genotype VII Newcastle Disease Virus

The Cre-recombinase mediated in vivo minicircle DNA vaccine platform (CRIM) provided a novel option to replace a traditional DNA vaccine. To further improve the immune response of our CRIM vaccine, we designed a dual promoter expression plasmid named pYL87 which could synthesize short HN protein under a prokaryotic in vivo promoter PpagC and full length HN protein of genotype VII Newcastle disease virus (NDV) under the previous eukaryotic CMV promoter at the same time. Making use of the self-lysed Salmonella strain as a delivery vesicle, chickens immunized with the pYL87 construction showed an increased serum haemagglutination inhibition antibody response, as well as an increased cell proliferation level and cellular IL-4 and IL-18 cytokines, compared with the previous CRIM vector pYL47. After the virus challenge, the pYL87 vector could provide 80% protection compared to 50% protection against genotype VII NDV in pYL47 immunized chickens, indicating a promising dual promoter strategy used in vaccine design.

Antibody Response and Protection After Receipt of Inactivated Influenza Vaccine: A Systematic Review.

Children are at increased risk of influenza-related complications. Public health agencies recommend 2 doses of influenza vaccine for children 6 months through 8 years of age receiving the vaccine for the first time. To systematically review studies comparing vaccine effectiveness (VE) and immunogenicity after 1 or 2 doses of inactivated influenza vaccine (IIV) in children. Data sources included Medline, Embase, and Cochrane Library databases. We included studies published in a peer reviewed journal up to April 2, 2019, with available abstracts, written in English, and with children aged 6 months through 8 years. VE among fully and partially vaccinated children was compared with that of unvaccinated children. We extracted geometric mean titers of serum hemagglutination inhibition (HAI) antibodies against influenza A(H1N1), A(H3N2), and B-lineage vaccine antigens after 1 and 2 IIV doses. Outcomes were evaluated by age, timing of doses, vaccine composition, and prevaccination titers. A total of 10 VE and 16 immunogenicity studies were included. VE was higher for fully vaccinated groups than partially vaccinated groups, especially for children aged 6-23 months. Our findings show increased HAI titers after 2 doses, compared with 1. Older children and groups with prevaccination antibodies have robust HAI titers after 1 dose. Similar vaccine strains across doses, not the timing of doses, positively affects immune response. Few studies focused on older children. Researchers typically administered one-half the standard dose of IIV. HAI antibodies are an imperfect correlate of protection. Findings support policies recommending 2 IIV doses in children to provide optimal protection against influenza.

The characterization of optimal selenized garlic polysaccharides and its immune and antioxidant activity in chickens

The purpose of this study was to optimize modification conditions of selenized garlic polysaccharides (sGPS) and investigate its structural characterization, immune and antioxidant activities. Herein, selenized garlic polysaccharides (sGPS) were prepared using by HNO3-Na2SeO3 selenylation method. And then modification conditions of sGPS were optimized through L9 (34) orthogonal test. The structural characterization of sGPS were identified by the Fourier-transform infrared (FT-IR), Solid-State nuclear magnetic resonance (NMR) spectra, X-ray diffraction (XRD) and thermogravimetric (TGA). The morphology of sGPS was detected using scanning electron microscope (SEM) and transmission electron microscope (TEM). In vivo investigation showed that sGPS significantly improved serum hemagglutination-inhibition (HI) antibody titers against Newcastle disease virus, enhanced secretory IgA (sIgA), IFN-γ, IL-2 secretion in jejunum and trachea irrigation compared with vaccine immunized control group. Furthermore, it showed that sGPS had some effects on the antioxidant activities in livers of chickens. In conclusion, the optimal modification conditions of sGPS were as follows: reaction temperature was 70 °C, the dosage of Na2SeO3 was 400 mg and reaction time was 6 h. The selenylation modification of garlic polysaccharides (GPS) could improve its immune and antioxidant activity in chickens.

The humoral immune response to high-dose influenza vaccine in persons with monoclonal B-cell lymphocytosis (MBL) and chronic lymphocytic leukemia (CLL)

BackgroundLimited data are available regarding the immunogenicity of high-dose influenza vaccine among persons with chronic lymphocytic leukemia (CLL) and monoclonal B cell lymphocytosis (MBL). MethodsA prospective pilot study of humoral immune responses to 2013–2014 and 2014–2015 high-dose trivalent influenza vaccine (HD IIV; Fluzone® High-Dose; Sanofi Pasteur) was conducted among individuals with MBL and previously untreated CLL. Serum hemagglutination inhibition (HAI) antibody titers were measured at baseline and Day 28 after vaccination; seroprotection and seroconversion rates were determined. Memory B cell responses were assessed by B-cell enzyme-linked immune absorbent spotassays. ResultsThirty subjects (17 CLL and 13 MBL) were included. Median age was 69.5 years. Day 28 seroprotection rates for the cohort were 19/30 (63.3%) for A/H1N1; 21/23 (91.3%) for A/H3N2; and 13/30 (43.3%) for influenza B. Those with MBL achieved higher day 28 HAI geometric mean titers (54.1 [4.9, 600.1] vs. 12.1 [1.3, 110.1]; p = 0.01) and higher Day 28 seroprotection rates (76.9% vs. 17.6%; p = 0.002) against the influenza B-vaccine strain virus than those with CLL. ConclusionsImmunogenicity of the HD IIV3 in patients with CLL and MBL is lower than reported in healthy adults. Immunogenicity to influenza B was greater in those with MBL than CLL.

Anti-Influenza Protective Efficacy of a H6 Virus-Like Particle in Chickens.

H6 avian influenza viruses (AIVs) have a worldwide distribution, and they pose a potential concern for public health. In Taiwan, H6 AIVs have circulated in domestic chickens for more than 40 years, and certain strains have crossed the species barrier to infect mammals. With the goal of containing the disease, there is a pressing need to develop a safe and effective vaccine for pandemic preparedness. In this study, we prepared a virus-like particle (VLP) that consisted of the hemagglutinin (HA) and matrix protein 1 (M1) derived from a H6 AIV as a vaccine antigen, and we examined the immunogenicity and protective efficacy when combined with an adjuvant in a chicken model. Full-length HA and M1 protein genes were cloned and expressed using a baculovirus expression system, and VLPs were purified from the supernatant of insect cell cultures. We performed nanoparticle-tracking analysis and transmission electron microscopy to validate that the particle structure and properties resembled the native virions. In animal experiments, specific-pathogen-free chickens that received the H6 VLPs in combination with an adjuvant showed superior H6N1 virus-specific serum IgG and hemagglutination-inhibition antibody responses, which lasted more than 112 days. Following the H6N1 viral challenge, the vaccinated chickens showed reduced viral replication in the lungs, kidneys and conjunctival/cloacal shedding. The antibodies induced in the chickens by the vaccine were able to cross-react with the H6N1 human isolate and drifted avian H6N1 isolates. In summary, the H6 VLP vaccine elicited superb immunogenicity in vivo, and the use of an adjuvant further enhanced the antiviral protective efficacy. This vaccine formulation could potentially be used to manage H6 influenza virus infections in chickens.

Humoral immune response against Newcastle disease virus and its pathological changes in vaccinated chickens in selected areas of Barisal district in Bangladesh

The objectives of this study were to evaluate humoral immunity against Newcastle disease (ND) virus in vaccinated chickens in terms of serum HI antibody titers in broiler and layer chickens and to determine pathological changes in vaccinated chickens. A total of 240 serum samples were collected from broiler (135) and layer (105) chickens from Barishal Sadar, Babugonj and Gournadi Upazilas of Barishal district in Bangladesh after two weeks of scheduled vaccination programme. The overall detection of Hemagglutination inhibition (HI) antibodies against Newcastle disease virus was 62.2% in broiler and 83.8% in layer chickens. The percentages of specific HI antibody titer in broiler chickens were 57.5, 70 and 48 in 1-2 weeks, 3-4 weeks, and 4-above weeks age groups respectively where in layer chickens were 85, 80, 90, 80 and 80 in 15-24 weeks, 25-34 weeks, 35-44 weeks, 45-54 weeks and > 55 weeks of age groups respectively. For both broiler and layer chicken’s protective antibody titers were found higher in adult than in young chickens. Out of 240 samples HI titers of 172 (71.67%) samples were found at protective level, 42 (17.5%) samples were at marginal level and 26 (10.83%) samples were below protective level. Among 26 samples of non-protective level, 21 were broiler and 5 were layer chicken. Out of 26 samples, 10 (38.46%) were found apparently infected with NDV where 8 (38.09%) were broiler and 2 (40%) were layer. The apparently infected birds were diagnosed on the basis of postmortem findings and histopathological lesions. Results of the present investigation may help to design appropriate vaccination schedule for ND in broiler and layer chickens and thus to protect chickens from ND in field condition.
 Asian J. Med. Biol. Res. June 2020, 6(2): 155-167

PUC18-CpG Is an Effective Adjuvant for a Duck Tembusu Virus Inactivated Vaccine.

Duck Tembusu virus (DTMUV) is an emerging pathogenic flavivirus responsible for massive economic losses in the duck industry. However, commercially inactivated DTMUV vaccines have been ineffective at inducing protective immunity in ducks. The widely used adjuvant cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODNs) reportedly improve humoral and cellular immunities in animal models. However, its effectiveness in DTMUV vaccines requires validation. Here, we assessed the protective efficacy of pUC18-CpG as an adjuvant in an inactivated live DTMUV vaccine in ducks. Our results revealed that the serum hemagglutination inhibition (HI) antibody titers, positive rates of anti-DTMUV antibodies, the concentration of serum cytokines, and protection efficacy were significantly increased in ducks immunized with pUC18-CpG compared to that in the control group. Moreover, ducks immunized with a full vaccine dose containing a half dose of antigen supplemented with 40 μg of pUC18-CpG exhibited the most potent responses. This study suggests that pUC18-CpG is a promising adjuvant against DTMUV, which might prove effective in treating other viral diseases in waterfowl.

Assessment of antibody responses to Newcastle disease vaccination in Nigerian indigenous chicken lines selected for sheep red blood cell antigen

This research was carried out to evaluate serum haemagglutination inhibition antibody titres to a Newcastle disease virus vaccine in two Nigerian indigenous chicken lines selected for sheep red blood cell antigens. One hundred Nigerian indigenous chickens were used. These chickens belonged to the fourth generation of flock that had been divergently distinguished into a high antibody titre chicken line (HATC) and a low antibody titre chicken line (LATC). Chicks were given a NDV vaccine at six weeks of age, while blood samples were collected from each chick at seven days post-administration. The antibody titres of chicks were determined through a haemagglutination inhibition test and the data collected were subjected to analysis of variance using SAS 9.2 version. It was found that sex had no significant effect on the antibody titre values (p>0.05), while the genetic line and sex by genetic line interaction had significant effects on the antibody titre values. Female chicks of LATC recorded a significantly lower ND antibody titre (4.21 ± 0.47) compared to HATC females (8.04 ± 2.02). Also, male chicks of LATC recorded a significantly lower ND antibody titre (4.26 ± 1.20) compared to HATC males (7.25 ± 0.48). Meanwhile, there was no significant difference between male and female chicks of LATC as well as between male and female chicks of HATC. Based on the differences observed in ND antibody titres between the genetic lines, emphasis should be placed on policies to develop HATC and LATC along ND resistance. Therefore, we recommend that when considering ND infection which exerts substantial losses to the poultry industry, HATC should be favoured over LATC.

Assessment of antibody responses to Newcastle disease vaccination in Nigerian indigenous chicken lines selected for sheep red blood cell antigen

This research was carried out to evaluate serum haemagglutination inhibition antibody titres to a Newcastle disease virus vaccine in two Nigerian indigenous chicken lines selected for sheep red blood cell antigens. One hundred Nigerian indigenous chickens were used. These chickens belonged to the fourth generation of flock that had been divergently distinguished into a high antibody titre chicken line (HATC) and a low antibody titre chicken line (LATC). Chicks were given a NDV vaccine at six weeks of age, while blood samples were collected from each chick at seven days post-administration. The antibody titres of chicks were determined through a haemagglutination inhibition test and the data collected were subjected to analysis of variance using SAS 9.2 version. It was found that sex had no significant effect on the antibody titre values (p>0.05), while the genetic line and sex by genetic line interaction had significant effects on the antibody titre values. Female chicks of LATC recorded a significantly lower ND antibody titre (4.21+0.47) compared to HATC females (8.04+2.02). Also, male chicks of LATC recorded a significantly lower ND antibody titre (4.26+1.20) compared to HATC males (7.25+0.48). Meanwhile, there was no significant difference between male and female chicks of LATC as well as between male and female chicks of HATC. Based on the differences observed in ND antibody titres between the genetic lines, emphasis should be placed on policies to develop HATC and LATC along ND resistance. Therefore, we recommend that when considering ND infection which exerts substantial losses to the poultry industry, HATC should be favoured over LATC.

A Novel Adjuvant "Sublancin" Enhances Immune Response in Specific Pathogen-Free Broiler Chickens Inoculated with Newcastle Disease Vaccine.

Sublancin is a glycosylated antimicrobial peptide produced by Bacillus subtilis 168 possessing antibacterial and immunomodulatory activities. This study was aimed at investigating the effects of sublancin on immune functions and serum antibody titer in specific pathogen-free (SPF) broiler chickens vaccinated with Newcastle disease (ND) vaccine. For this purpose, 3 experiments were performed. Experiment 1: SPF broiler chicks (14 days old) were randomly allotted to 1 of 7 groups including a blank control (BC), vaccine control (VC), and 5 (3-7) vaccinated and sublancin supplemented at 5, 15, 30, 45, and 60 mg activity/L of water, respectively. Vaccinated groups (2-7) were vaccinated with ND vaccine by intranasal and intraocular routes at the 14th day. On 7, 14, 21, and 28 days post vaccination (dpv), the blood samples were collected for the determination of serum hemagglutination inhibition (HI) antibody titer. Experiment 2: SPF broiler chicks were divided into 1 of 3 groups, i.e., blank control (BC), vaccine control (VC), and sublancin treatment (ST). On 7, 14, and 21 dpv, the blood samples were collected for measuring HI antibody titer by micromethod. Experiment 3: the design of this experiment was the same as that of experiment 2. On 7 and 21 dpv, pinocytosis of peritoneal macrophages, B lymphocyte proliferation assay, measurement of CD4+ and CD8+ T cells, and serum cytokine quantitation were carried out. It was noted that sublancin promoted B lymphocyte proliferation, increased the proportion of CD8+ T lymphocyte subpopulations, and enhanced the antibody titer in broiler chickens. In addition, it was also observed that sublancin has the potential to induce the secretion of IFN-γ, IL-10, and IL-4. In conclusion, these findings suggested that sublancin could promote both humoral and cellular immune responses and has the potential to be a promising vaccine adjuvant.

Nano-emulsion as a vaccine adjuvant can enhance the humoral immunity against influenza in aged and young mice

Objective To evaluate the immunogenicity of split influenza H1N1 vaccine formulated with an oil-in-water nano-emulsion adjuvant in aged mice and young mice. Methods A nano-emulsion adjuvant formulated split influenza H1N1 vaccine was used to immunize aged and young mice through intramuscular injection. Each mouse was immunized with 0.012 μg of hemagglutinin (HA) twice with an interval of 28 d. Hemagglutination inhibition (HI) titers in serum were measured 27 d after first immunization. Serum HI, IgG1 and IgG2a titers were detected 14 d after the last immunization. No adjuvant-formulated vaccine and normal saline (NS) were used to set up control groups. Virus challenge test was carried out using 10 times the median lethal dose (LD50) of A/Puerto Rico/8/34 (H1N1) strain two weeks after the last immunization and the protective effects were assessed through measuring the dynamic changes in body weight and survival rate. Results Higher levels of serum HI, IgG1 and IgG2a antibodies and higher HI antibody conversion rates were induced in the adjuvant groups, especially in the aged mice group, than in the control groups. Nano-emulsion adjuvant improved the immunogenicity of HA and mouse immunity to A/Puerto Rico/8/34 (H1N1). Conclusions Nano-emulsion adjuvant could enhance the immunogenicity of influenza antigens, especially in aged mice. Key words: Adjuvant; Influenza; Nano-emulsion adjuvant; Aged mice; Immunogenicity

Immunogenicity and Safety of Influenza Vaccination in Cancer Patients Receiving Immune Checkpoint Inhibitor

Background: Immune checkpoint inhibitors (ICIs) were recently introduced into routine clinical practice, but the immunogenicity and safety of influenza vaccination in cancer patients receiving ICIs have not been elucidated. We explored immunogenicity and safety in cancer patients receiving ICIs compared to cancer patients receiving cytotoxic chemotherapy. Methods: Adult cancer patients receiving ICIs or cytotoxic agents were prospectively enrolled in a 1:2 ratio. They received an intramuscular seasonal quadrivalent influenza vaccine on day 1 of the chemotherapeutic cycle. The serum hemagglutination inhibition (HAI) antibody titers were examined before and 4 weeks after vaccination. The primary endpoint was seroprotection rate and secondary endpoints were seroconversion rate and geometric mean antibody titer. Immune-related adverse events (irAEs) were screened by pre-defined measures. Findings: Among 154 eligible patients, 46 and 90 patients in the ICI and cytotoxic chemotherapy groups, respectively, were finally examined for HAI antibody titers. Seroprotection rates were higher in the ICI group than in the cytotoxic chemotherapy group (H1N1, 76% vs. 68%, P=0.111; H3N2, 89% vs. 70%, P=0.005; B-Yamagata, 83% vs. 54%, P=0.002; B-Victoria, 85% vs. 48%, P<0.001) and seroconversion rates were also higher in the ICI group (H1N1, 57% vs. 39%, P=0.086; H3N2, 52% vs. 27%, P=0.006; B-Yamagata, 54% vs. 30%, P=0.007; B-Victoria, 65% vs. 28%, P<0.001). The frequency of vaccine-related adverse events was comparable between the two groups. Only 4 (8.5%) irAEs occurred during the study period, which were all grade 1. Interpretation: Cancer patients receiving ICIs reach higher levels of influenza immunity by vaccination than those receiving cytotoxic chemotherapy, without increased frequency or severity of irAEs. Annual influenza vaccination should be encouraged in cancer patients receiving ICIs. Trial Registration Number: The study was registered at ClinicalTrials.gov (identifier NCT03590808). Funding Statement: GC Pharma (Yongin, Republic of Korea) and Seoul National University Hospital Research Fund (Seoul, Republic of Korea; No.04-2018-0520). Declaration of Interests: BK reports grants and personal fees from AstraZeneca, grants and personal fees from MSD, grants from ONO Pharmaceutical, personal fees from Genexine, outside the submitted work. S-AI reports grants and personal fees from AstraZeneca, grants and personal fees from Pfizer, personal fees from Amgen, personal fees from Eisai, personal fees from Hanmi Corp., personal fees from Novartis, personal fees from Roche, outside the submitted work. WBP reports grants from GC Pharma, grants from Seoul National University Hospital Research Fund, during the conduct of the study. All other authors declare no competing interests. Seoul National University Hospital reports grants from Alpha Biopharma, grants from AstraZeneca/MedImmune, grants from Hanmi Corp., grants from Janssen, grants from Merus, grants from Mirati Therapeutics, grants from MSD, grants from Novartis, grants from ONO Pharmaceutical, grants from Pfizer, grants from Roche/Genentech, grants from Takeda, grants from TP Therapeutics, grants from Xcovery, grants from Yuhan, outside the submitted work. Ethics Approval Statement: Written informed consents were obtained from all participants prior to vaccination. The study was approved by the Institutional Review Board of Seoul National University Hospital (IRB approval No. H-1806-088-951) and Seoul National University Bundang Hospital (IRB approval No. B-1808/484- 402).