Serum Antibody Titers Research Articles

Enhancing effect of oregano essential oil and Bacillus subtilis on broiler immune function, intestinal morphology and growth performance

The present study evaluated the effect of two categories of feed additives on chicken performance through immunological and intestinal histo-morphometric measurements. A total of 150 one-day-old male broiler chicks (Cobb) were randomly assigned to three groups. Group I received a non-supplemented basal diet. While groups II and III were treated with a basal diet supplemented with oregano essential oil (OEO) and Bacillus subtilis, respectively, in water for 28 days. Blood samples were taken at 6, 18 and 28 days for hematological analysis, phagocytosis, lymphocyte proliferation and measuring antibody responses. Additionally, growth performance indices were recorded weekly. The results showed that groups supplemented with OEO and B. subtilis improved growth performance expressed by a significant increase in weight gain (P < 0.05), with a significant reduction (P < 0.05) in feed conversion ratio (FCR). Hematological findings indicated a significant increase in blood parameters as well as a significant increase in phagocytic % & phagocytic index at all time points with a greater probiotic effect. On the other hand, OEO produced a significant increase in lymphocyte proliferation at 18 & 28 days. Humoral immunity revealed a significant increase in serum antibody titer phytobiotic & probiotic-fed groups at time points of 18 & 28 days with a superior phytobiotic effect. The histological examination showed a significant increase in villi length, villi width, crypt depth & V/C ratio. In conclusion, these results indicated positive effects of B. subtilis & OEO on both growth and immunity and could be considered effective alternatives to the antibiotic.

A Case Report on Transverse Myelitis

Scrub typhus is known to cause central nervous system involvement, which can show as meningitis or meningoencephalitis. However, relatively few reports of acute transverse myelitis (ATM), a spinal cord lesion, have been linked to scrub typhus. Patients with a spinal lesion and scrub typhus have neurologic symptoms such as dysuria and sensory and motor impairment. Here, we report on an uncommon instance of ATM linked to scrub typhus. The diagnosis of ATM linked with scrub typhus was made based on the patient’s clinical features, cerebral fluid cytology, Orientia tsutsugamushi serum antibody titer, and several magnetic resonance imaging scans.

Long-term analysis of humoral responses and spike-specific T cell memory to Omicron variants after different COVID-19 vaccine regimens.

The emergence of SARS-CoV-2 variants has raised concerns about the sustainability of vaccine-induced immunity. Little is known about the long-term humoral responses and spike-specific T cell memory to Omicron variants, with specific attention to BA.4/5, BQ.1.1, and XBB.1. We assessed immune responses in 50 uninfected individuals who received varying three-dose vaccination combinations (2X AstraZeneca + 1X Moderna, 1X AstraZeneca + 2X Moderna, and 3X Moderna) against wild-type (WT) and Omicron variants at eight months post-vaccination. The serum antibody titers were analyzed by enzyme-linked immunosorbent assays (ELISA), and neutralizing activities were examined by pseudovirus and infectious SARS-CoV-2 neutralization assays. T cell reactivities and their memory phenotypes were determined by flow cytometry. We found that RBD-specific antibody titers, neutralizing activities, and CD4+ T cell reactivities were reduced against Omicron variants compared to WT. In contrast, CD8+ T cell responses, central memory, effector memory, and CD45RA+ effector memory T cells remained unaffected upon stimulation with the Omicron peptide pool. Notably, CD4+ effector memory T cells even exhibited a higher proportion of reactivity against Omicron variants. Furthermore, participants who received three doses of the Moderna showed a more robust response regarding neutralization and CD8+ T cell reactions than other three-dose vaccination groups. Reduction of humoral and CD4+ T cell responses against Omicron variants in vaccinees suggested that vaccine effectiveness after eight months may not have sufficient protection against the new emerging variants, which provides valuable information for future vaccination strategies such as receiving BA.4/5 or XBB.1-based bivalent vaccines.

Correlation between the Fasciola hepatica infection rate (number of parasites in the liver parenchyma) and the antibody titration, detected by ELISA assay.

This study aimed to demonstrate the existence of a possible correlation between the level of liver fluke infection in cattle caused by Fasciola hepatica and the titers of anti-parasite antibodies in the blood. 113 blood samples were taken from non-dewormed pasture cattle in the communal slaughterhouse of the Jijel city in order to determine the serological titration of anti-fluke antibodies by the ELISA method. After slaughtering the animals studied, a count of parasites present in the inspected livers was carried out in order to assess the level of parasitic infection. The prevalence of bovine fasciolosis (due to Fasciola hepatica) based on counting the number of flukes in the inspected livers was around 61.06%, while the seroprevalence obtained is 55.75%. The sensitivity and specificity of the ELISA test used in this study were, respectively, 91.3% and 100%. A very strong correlation (r = 0.93 to p < 0.0001) was statistically demonstrated between the antibody titers and the number of flukes in the inspected livers. According to the results of this study, there is a strong statistical correlation between serum antibody titers and the number of flukes present in the liver (the higher the number of parasites in the liver, the higher the level of anti-flukes antibodies in the blood).

Immuno-protective response of Asian seabass (Lates calcarifer) to inactivated vaccines against Streptococcus iniae and Vibrio harveyi

BackgroundIn this study, the protective immunity and immunogenicity of the monovalent and bivalent Streptococcus iniae and Vibrio harveyi vaccine were evaluated in Asian seabass. To analyze immune responses, 1200 Asian seabass with an average weight of 132.6 ± 25.4 g were divided into eight treatments in triplicates (50 fish per tank) as follows: S. iniae immunized by injection (SI), V. harveyi immunized by injection (VI), bivalent S. iniae and V. harveyi (SVI) immunized by injection, S. iniae immunized by immersion (SIM), V. harveyi (VIM) immunized by immersion, bivalent S. iniae and V. harvei (SVIM) immunized by immersion, phosphate-buffered saline (PBS) by injection (PBSI) and control group without vaccine administration (CTRL). Blood and serum samples were taken at the end of the 30th and 60th days. Then the vaccinated groups were challenged with two bacteria (S. iniae) and (V. harveyi) separately and mortality was recorded for 14 days.ResultsThis study reveals that there is no significant difference in the hematological parameters on the 30th and 60th days of the experiment in the vaccine-immunized groups compared to the CTRL group (P > 0.05). Meanwhile, there was no significant difference in the amount of serum albumin level, respiratory burst activity, and serum bactericidal activity in the vaccine-immunized groups compared to the CTRL group on the 30th and 60th days of the experiment (P > 0.05). Total protein on the 60th day (in the VI and SVI groups), globulin on the 30th day (in the VI and SVI groups) and the 60th day (in the VI group) compared to the CTRL and PBSI groups had a significant increase (P < 0.05). Complement activity (in the VI and SVI groups) and lysozyme (in the SI and SVI groups) increased significantly compared to the control group (P < 0.05). Serum antibody titer against S. iniae had a significant increase in the SI, VI, SVI and SVIM groups compared to the CTRL and PBSI groups (P < 0.05). Serum antibody titer against V. harveyi had a significant increase in the groups immunized with the vaccine compared to the CTRL and PBSI groups (P < 0.05). A significant increase in the relative percentage survival (RPS) following challenge with S. iniae in the SVI (86.6%), SI (83.3%,) and VI (73.3%) groups were observed compared to the CTRL (43.3%) and PBSI (40%) groups (P < 0.05). Also, a significant increase in the RPS after challenge with V. harveyi in the SVI group, VI 86.6%, SVI 83.3%, VIM 80% and SVIM 76.6% were observed compared to the CTRL (46.6%) and PBSI (50%) groups (P < 0.05).ConclusionOverall, the results demonstrated that the bivalent vaccine of S. iniae and V. harveywas able to produce significant immunogenicity and RPS in Asian seabass

PGM-CSF as an adjuvant in DNA vaccination against SARS-CoV-2

The emergence of SARS-CoV-2 presents a significant global public health dilemma. Vaccination has long been recognized as the most effective means of preventing the spread of infectious diseases. DNA vaccines have attracted attention due to their safety profile, cost-effectiveness, and ease of production. This study aims to assess the efficacy of plasmid-encoding GM-CSF (pGM-CSF) as an adjuvant to augment the specific humoral and cellular immune response elicited by DNA vaccines based on the receptor-binding domain (RBD) antigen. Compared to the use of plasmid-encoded RBD (pRBD) alone, mice that were immunized with a combination of pRBD and pGM-CSF exhibited significantly elevated levels of RBD-specific antibody titers in serum, BALF, and nasal wash. Furthermore, these mice generated more potent neutralization antibodies against both the wild-type and Omicron pseudovirus, as well as the ancestral virus. In addition, pGM-CSF enhanced pRBD-induced CD4+ and CD8+ T cell responses and promoted central memory T cells storage in the spleen. At the same time, tissue-resident memory T (Trm) cells in the lung also increased significantly, and higher levels of specific responses were maintained 60 days post the final immunization. pGM-CSF may play an adjuvant role by promoting antigen expression, immune cells recruitment and GC B cell responses. In conclusion, pGM-CSF may be an effective adjuvant candidate for the DNA vaccines against SARS-CoV-2.

Evaluation of immunomodulatory (humoral as well as cell-mediated) and cytokines (TNF-α & IL-10) regulating potential of Neolamarckia cadamba fruit extract in Wistar albino rats.

Current work has been designed to investigate the immunomodulatory efficacy with particular reference to humoral, cell-mediated and cytokine-modulating potential of hot aqueous extract of Neolamarckia cadamba (HAENC) fruits in Wistar albino rats. The effect of different concentrations of HAENC fruits over cell-mediated immune response was assessed using six groups (Gp-I as control, Gp-II with 20µg/mL, Gp-III with 50µg/mL, Gp-IV with 100µg/mL, Gp-V with 250µg/mL, and Gp-VI with 500µg/mL) of Wistar albino rats having six animals in each. The amount of tumor necrosis factor-α (TNF-α) and interleukin (IL)-10 was measured by sandwich ELISA with different concentrations of HAENC (50-500µg/mL) in splenocyte culture supernatant and their expression was determined by qRT-PCR Humoral immune response was determined by measuring the serum antibody titer of Wistar albino rats against Salmonella typhimurium 'O' antigen using four groups containing six animals each (Gp-I as control, Gp II, III & IV were respectively fed orally with 125, 250, and 500mg/Kg body weight using HAENC fruits). LC-MS analysis suggested the presence of cadambine, chlorogenic acid, cadambagenic acid, stearic acid, octadecanoic acid ethyl ether, and 7-hydroxy-5,2'-4'-trimethoxyflavonon in the extract based on their m/z ratio. The result suggested significant (p < 0.01) dose-dependent proliferation of Concanavalin A (Con A)-treated splenocytes, depicting cell-mediated immunostimulatory potential of HAENC fruits. A dose-dependent significant decrease (p < 0.01) was found in the amount of TNF-α and IL-10 was found to increase significantly (p < 0.01) as extract concentrations increased. TNF-α and IL-10 expressions were confirmed at the molecular level by qRT-PCR analysis of mRNA transcripts of TNF-α and IL-10 genes. Fold expression of TNF-α and IL-10 gene was 0.197 and 3.58 at 250µg/mL, 0.02 and 20.11 at 500µg/mL concentrations of HAENC respectively in comparison to control. Serum antibody titer was significantly increased (p < 0.01) in animals fed with different doses of HAENC fruits. The present study suggested the anti-inflammatory effect of HAENC fruits which also influences the networking of cytokines, implying that it may play a role in regulating the activity of the host's immune system and can serve as a potent herbal drug with immuno-stimulatory potential.

Immune stimulatory effect of Nigella sativa in healthy animal models: A systematic review and meta-analysis

The immune-modulatory effects of black seeds (Nigella sativa seeds, NSS) are well documented, but the overall in vivo impact of this important natural medicinal product on immune system function has yet to be established. Here we systematically reviewed and meta-analyzed the effects of NSS on humoral [serum titers of immunoglobulins including IgG, IgM, anti-Newcastle virus disease (anti-NDV), and sheep red blood cell antigen (anti-SRBC)] and cellular immunity [total white blood cell (WBC) count and percentages of monocytes, lymphocytes, basophils, neutrophils, and eosinophils] in healthy animals. The PubMed, ScienceDirect, Web of Science, and Scopus databases were searched according to predefined eligibility criteria. Meta-analyses were performed to estimate the final effect size using RevMan software. Seventeen animal studies were eligible for analysis. For humoral immunity, the overall pooled effect size (ES) of NSS on serum titers of IgM and anti-NVD antibodies was not significantly different [mean difference (MD) 75.27, 95% CI: −44.76 to 195.30, p = 0.22 (I2 = 89%, p = 0.003), and −0.01, 95% CI: −0.27 to 0.25, p = 0.94 (I2 = 74%, p = 0.02), respectively]. However, NSS significantly increased serum titers of IgG and anti-SRBC antibodies [MD 3.30, 95% CI: 2.27 to 4.32, p = 0.00001 (I2 = 0%, p = 0.97), and 1.15, 95% CI: 0.74 to 1.56, p = 0.00001 (I2 = 0%, p = 0.43), respectively]. For cellular immunity, the ES of NSS on WBCs, monocytes, and lymphocytes were not significantly different [MD 0.29, 95% CI: −0.55 to 1.13, p = 0.50, (I2 = 14%, p = 0.32), - 0.01, 95% CI: −0.45 to 0.44, p = 0.97 (I2 = 0%, p = 0.77), and 4.73, 95% CI: −7.13 to 16.59, p = 0.43, (I2 = 99%, p = 0.00001), respectively]. In conclusion, black seeds enhance humoral immunity in healthy animals but do not affect cellular immunity.

Dosing of Convalescent Plasma and Hyperimmune Anti-SARS-CoV-2 Immunoglobulins: A Phase I/II Dose-Finding Study.

During the COVID-19 pandemic, trials on convalescent plasma (ConvP) were performed without preceding dose-finding studies. This study aimed to assess potential protective dosing regimens by constructing a population pharmacokinetic (popPK) model describing anti-SARS-CoV-2 antibody titers following the administration of ConvP or hyperimmune globulins (COVIg). Immunocompromised patients, testing negative for anti-SARS-CoV-2 spike antibodies despite vaccination, received a range of anti-SARS-CoV-2 antibodies in the form of COVIg or ConvP infusion. The popPK analysis was performed using NONMEM v7.4. Monte Carlo simulations were performed to assess potential COVIg and ConvP dosing regimens for prevention of COVID-19. Forty-four patients were enrolled, and data from 42 were used for constructing the popPK model. A two-compartment elimination model with mixed residual error best described the Nab-titers after administration. Inter-individual variation was associated to CL (44.3%), V1 (27.3%), and V2 (29.2%). Lean body weight and type of treatment (ConvP/COVIg) were associated with V1 and V2, respectively. Median elimination half-life was 20 days (interquartile range: 17-25days). Simulations demonstrated that even monthly infusions of 600mL of the ConvP or COVIg used in this trial would not achieve potentially protective serum antibody titers for >90% of the time. However, as a result of hybrid immunity and/or repeated vaccination, plasma donors with extremely high antibody titers are now readily available, and a >90% target attainment should be possible. The results of this study may inform future intervention studies on the prophylactic and therapeutic use of antiviral antibodies in the form of ConvP or COVIg. NL9379 (The Netherlands Trial Register).

Intranasal vaccine for Lyme disease provides protection against tick transmitted Borrelia burgdorferi beyond one year

Strategies for disease control are necessary to reduce incidence of Lyme Disease (LD) including development of safe vaccines for human use. Parainfluenza virus 5 (PIV5) vector has an excellent safety record in animals and PIV5-vectored vaccines are currently under clinical development. We constructed PIV5-vectored LD vaccine candidates expressing OspA from B. burgdorferi (OspAB31) and a chimeric protein containing sequences from B. burgdorferi and B. afzelii (OspABPBPk). Immunogenicity and vaccine efficacy were analyzed in C3H-HeN mice after prime-boost intranasal vaccination with live PIV5-OspAB31 or PIV5-OspABPBPk, subcutaneous (s.c.) vaccination with rOspAB31+Alum, and the respective controls. Mice vaccinated intranasally with live PIV5-AB31 or PIV5-ABPBPk had higher endpoint titers of serum antibody against OspAB31 at 6- and 12- months post vaccination, compared to mice vaccinated s.c. with rOspAB31. Neutralization activity of antibody was maintained up to 18-months post-immunization, with the response greater in live PIV5-delivered OspA vaccines, than that induced by s.c. rOspAB31. Challenge with infected ticks carrying 10-19 strains of B. burgdorferi performed at 4-, 9- or 15-months post-immunization showed increased breakthrough infections in mice vaccinated with s.c. rOspAB31 compared to intranasal PIV5-AB31 or PIV5-ABPBPk at 9- and 15-months, as determined by quantification of serologic antibodies to B. burgdorferi proteins as well as flaB DNA in tissues, and by visualization of motile B. burgdorferi in culture of tissues under dark field microscope. These findings indicate that immunization of mice with PIV5 delivered OspA generates immune responses that produce longer-lasting protection ( > 1 year) against tick-transmitted B. burgdorferi than a parenteral recombinant OspA vaccine.

Bone marrow plasma cells require P2RX4 to sense extracellular ATP.

Plasma cells produce large quantities ofantibodies and so play essential roles in immune protection1. Plasma cells, including a long-lived subset, reside in the bone marrow where they depend on poorly defined microenvironment-linked survival signals1. We show that bone marrow plasma cells use the ligand-gated purinergic ion channel P2RX4 to sense extracellular ATP released by bone marrow osteoblasts through the gap-junction protein pannexin 3 (PANX3). Mutation of Panx3 or P2rx4 each caused decreased serum antibodies and selective loss of bone marrow plasma cells. Compared to their wild-type counterparts, PANX3-null osteoblasts secreted less extracellular ATP and failed to support plasma cells in vitro. The P2RX4-specific inhibitor 5-BDBD abrogated the impact of extracellular ATP on bone marrow plasma cells in vitro, depleted bone marrow plasma cells in vivo and reduced pre-induced antigen-specific serum antibody titre with little posttreatment rebound. P2RX4 blockade also reduced autoantibody titre and kidney disease in two mouse models of humoral autoimmunity. P2RX4 promotes plasma cell survival by regulating endoplasmic reticulum homeostasis, as short-term P2RX4 blockade caused accumulation of endoplasmic reticulum stress-associated regulatory proteins including ATF4 and B-lineage mutation of the pro-apoptotic ATF4 target Chop prevented bone marrow plasma cell demise on P2RX4 inhibition. Thus, generating mature protective and pathogenic plasma cells requires P2RX4 signalling controlled by PANX3-regulated extracellular ATP release from bone marrow niche cells.

Seasonal Testing, Results, and Effect of the Pandemic on Coxsackievirus Serum Studies.

Coxsackieviruses (CVs) are common causes of infections and can be life-threatening. Unfortunately, rigorous studies guiding the clinician in interpreting CV serum antibody titer testing is lacking. To explore the epidemiology of circulating CVs and the serological test utility in aiding diagnosis of CV infections in our community, we obtained results of CV immunologic diagnostic tests between 2018 and 2022 from a regional healthcare database. For CV type A, rare individuals had positive CF (complement fixation) tests whereas all 16 individuals with IFA testing showed at least one positive serotype. For CV type B CF testing, 52.2% of 222 patients had at least one serotype positive, with B5 being most common and also the most common with higher titers (14.8% with ≥1:32). We found a significant reduction in seropositivity rate during the pandemic in 2020 compared to 2018, which continued through 2022 (OR: 0.2, 95% CI: 0.08-0.49, p-value < 0.001). During the pandemic, the seasonal pattern of positive tests varied from the pre-pandemic pattern. Testing for CVs was increased after the first year of the pandemic. Overall, the variability by month and seasonal change in our data support that CF testing can be used to identify recent CVB infection.

The Efficacy of Nile Tilapia Vaccination by Formalin killed Streptococcus agalactiae Encapsulated in Alginate Microcapsules

Nile tilapia is one of the major farmed fish that is often infected with Streptococcus. Oral vaccination is the most preferable technique, but the antigen is usually degraded by gastric juice. Encapsulation by alginate could be effective in protecting the antigen. The aim of this study was to assess the effectiveness of vaccinating Nile tilapia using formalin-killed Streptococcus agalactiae encapsulated in alginate. The average diameter of fabricated microcapsules was 500±20 μm, with 86% encapsulation efficacy. Fish were then divided into four groups (30 fish per group): group A: fish vaccinated by alginate microcapsules covered by formalin-killed cells (FKC), group B: fish vaccinated by non-covered FKC, group C: fish fed with empty alginate microcapsules and group D: fish feed with commercial pellets as control group. All groups were treated for 14 days and then fed with commercial pellets. Blood samples were collected on days 7, 14, 21, and 28 days post-vaccination. Bactericidal activity, lysozyme activity and serum antibody titer were significantly elevated in group A (p&lt;0.001) compared to other treated groups. Then, gene expression analysis was performed at 29 days post-vaccination to evaluate the expression of main immune contributors such IgM, IgT, TCR β, CD4, CD8α, IL 1β, IL 8, IFN 1, and TNFα. The analysis showed significant upregulation of all tested genes in group A compared to other treated groups (p&lt;0.001). Lastly, a challenge test was done on day 30 post-vaccination by injecting 4.6×106 CFU mL−1 of virulent S. agalactiae. The relative percent of survival (RPS) were 92± 2%, 48± 5% and 4± 3% for groups A, B and C respectively. The obtained result indicated that alginate encapsulation provided antigen protection due to its higher immunogenicity compared to non-covered vaccine. Hence, the fabricated vaccine could be incorporated with food and orally administered to Nile tilapia to prevent S. agalactiae infection.

Construction of recombinant Lactococcus expressing thymosin and interferon fusion protein and its application as an immune adjuvant

BackgroundIn recent years, biosafety and green food safety standards have increased the demand for immune enhancers and adjuvants. In the present study, recombinant food-grade Lactococcus lactis (r-L. lactis-Tα1-IFN) expressing thymosin Tα1 and chicken interferon fusion protein was constructed.ResultsThe in vitro interactions with macrophages revealed a mixture of recombinant r-L. lactis-Tα1-IFN could significantly activate both macrophage J774-Dual™ NF-κB and interferon regulator (IRF) signaling pathways. In vitro interactions with chicken peripheral blood mononuclear cells (PBMCs) demonstrated that a mixture of recombinant r-L. lactis-Tα1-IFN significantly enhanced the expression levels of interferon (IFN)-γ, interleukin (IL)-10, CD80, and CD86 proteins in chicken PBMCs. Animal experiments displayed that injecting a lysis mixture of recombinant r-L. lactis-Tα1-IFN could significantly activate the proliferation of T cells and antigen-presenting cells in chicken PBMCs. Moreover, 16S analysis of intestinal microbiota demonstrated that injection of the lysis mixture of recombinant r-L. lactis-Tα1-IFN could significantly improve the structure and composition of chicken intestinal microbiota, with a significant increase in probiotic genera, such as Lactobacillus spp. Results of animal experiments using the lysis mixture of recombinant r-L. lactis-Tα1-IFN as an immune adjuvant for inactivated chicken Newcastle disease vaccine showed that the serum antibody titers of the experimental group were significantly higher than those of the vaccine control group, and the expression levels of cytokines IFN-γ and IL-2 were significantly higher than those of the vaccine control group.ConclusionThese results indicate that food-safe recombinant r-L. lactis-Tα1-IFN has potential as a vaccine immune booster and immune adjuvant. This study lays the foundation for the development of natural green novel animal immune booster or immune adjuvant.

Immunogenicity of inactivated H5 avian influenza vaccine used in commercial laying pullet in Tehran province

Highly pathogenic avian influenza (HPAI) is a viral disease caused by some H5 and H7 subtypes of influenza virus type A in most species of birds, especially poultry. HPAI viruses are amongst the most challenging viruses that threaten both human and animal health. Consequently, various strategies such as the use of vaccines have been proposed to control the disease. After a catastrophic pandemic and the failure of conventional methods (elimination and extermination) in Iran, multiple vaccines has been used to control the disease. This study investigates the immunogenicity of two recombinant inactivated commercial vaccines of H5N1 and H5N3 subtypes in laying pullet flocks in Tehran Province, Iran. From 32 halls in 6 breeding units of laying pullets, 3200 sera and 800 tracheal and cloacal swabs were collected. After collecting the samples, Serum neutralisation (SN) and hemagglutination inhibition (HI) tests were conducted on sera to determine the serum titers of H5 specific antibody obtained from vaccine inoculation in three steps: before, after first vaccination and after the second vaccination (booster). SN and HI tests were carried out by the alpha and beta methods on the pooled samples by the vaccine type (as antigen for HI and SN), and the results were compared. The PCR was performed on the tracheal and cloacal swab samples to possibly detect the HA (H5)virus in the studied flocks. The HI test results showed that both vaccines had a Serum antibody titre above 5 (log2) after two vaccination rounds, indicating a desirable immunogenic response. The SN test results also showed a neutralisation index above 104.5 for both vaccines, indicating more than 50% reduction in antigenicity of the virus. The PCR results were negative. This study was the first investigation of immunogenicity following two-time vaccination against H5 subtype vaccines in Iranian poultry flocks, indicated suitable antibody titer against the influenza virus in vaccinated flocks.

Generation of JC Polyoma Pseudovirus for High-Throughput Measurement of Neutralizing Antibodies

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by reactivation of dormant JC polyomavirus (JCPyV). PML was mainly observed in immunocompromised individuals, such as HIV-positive patients, autoimmune disease patients, and cancer patients. Given that the presence of anti-JCPyV antibodies in serum is a risk indicator for PML development, it is essential to monitor anti-JCPyV antibody levels. In the present study, we established reporter-based single-infection neutralization assays for JCPyV and the genetically similar BK polyoma virus (BKPyV). We then confirmed the lack of cross-reactivity between the two viruses using test sera obtained from mice immunized with plasmids encoding the JCPyV or BKPyV capsid. Next, we compared neutralization antibody titers in sera from healthy donors, patients with multiple sclerosis (MS), and HIV-positive patients using an in-house enzyme-linked immunosorbent assay (ELISA) with JCPyV-like particles (virus-like particles; VLPs). A positive correlation was demonstrated between the neutralization titer (75% infectious concentration; IC75) against JCPyV and the antibody titer obtained by VLP-based JCPyV ELISA. This assay system may be applied to detect antibodies against other PyVs by generation of pseudoviruses using the respective capsid expression plasmids, and is expected to contribute to the surveillance of PyV as well as basic research on these viruses.

P914 Immunogenecity of Hepatitis B Vaccination in Patients with Ulcerative Colitis on Infliximab Monotherapy : A Prospective Comparative Study

Abstract Background Hepatitis B virus (HBV) infection has been associated with chronic hepatitis and cirrhosis. Patients with inflammatory bowel disease (IBD) maybe at higher risk of HBV infection, especially those on biologic therapies. There is limited data on the effectiveness of HBV vaccination in patients with IBD receiving different types of IBD medications. This study intends to compare the effectiveness of HBV vaccine in patients with ulcerative colitis (UC) on Infliximab (IFX) compared to those on 5-aminosalicylic acid (5-ASA). Methods Patients with UC aged between 18-85 years were prospectively enrolled in the study. The patients were divided into two groups: group 1 ( patients with UC on 5-ASA) and group 2 (patients with UC on IFX). HBV vaccination was administered (20 mcg) following the standard regimen, and Hepatitis B serum antibody (HbsAb) titres were assessed three months after the final dose. The response to HBV vaccines was categorized as 'adequate' immune response (≥10 IU/L) and 'effective' immune response (≥100 IU/L). Results In our final analysis of 118 patients with UC, 54.2% were male, and 52.5% had extensive disease. HBsAb titer levels were significantly higher in the 5ASA group (126.7 ± 37.5) compared to the IFX group (55.5 ± 29.4). Stratifying HBsAb levels into two categories (≥10-99 IU/L and ≥100 IU/L) revealed a significantly greater proportion of subjects in the 5-ASA group with levels ≥100 IU/L (76.7%) compared to the IFX group (12.1%). Conversely, the IFX group showed a higher percentage of subjects with levels between 10-99 IU/L (87.9%) relative to the 5-ASA group (23.3%). Logistic regression analysis demonstrated that patients with UC receiving 5-ASA were 23.94 times more likely to exhibit HBsAb levels ≥100 compared to those on IFX (OR 23.94, 95% CI 8.89-64.49). Conclusion Immune response to hepatitis B vaccination in patient with ulcerative colitis on infliximab is attenuated compared to those on 5-ASA. Therefore emphasizing the importance of HBV vaccination for patients with IBD before starting anti-TNF therapy, especially infliximab, and advocating for screening is imperative in high risk countries.

In Vitro Protection and Titer Duration of Anthrax-Specific Antibodies Following Subcutaneous Vaccination of White-tailed Deer (Odocoileus virginianus) with Bacillus anthracis Sterne 34F2 Strain Spores.

Outbreaks of anthrax, caused by the soilborne bacterium Bacillus anthracis, are a continuous threat to free-ranging livestock and wildlife in enzootic regions of the United States, sometimes causing mass mortalities. Injectable anthrax vaccines are commercially available for use in livestock, and although hand injection is not a cost- or time-effective long-term management plan for prevention in wildlife, it may provide a tool for managers to target selectively animals of high conservation or economic value. Vaccine-induced anthrax-specific antibody responses have been reported previously in white-tailed deer (Odocoileus virginianus), but the protective nature was not determined. In this study, five white-tailed deer were subcutaneously vaccinated with one dose (1 mL) of the Anthrax Spore Vaccine. Eight blood collections by jugular venipuncture were conducted over 146 d to measure the anthrax-specific antibody response in each deer's serum over time. Antibodies were first detected by ELISA and later with toxin neutralization assays to estimate in vitro protection. Average peak absorbance by ELISA occurred at 14 d postvaccination, whereas average peak in vitro protection occurred at 28 d postvaccination. Observed in vitro protection on average for white-tailed deer after this single-dose vaccination protocol lasted 42-56 d postvaccination, although three individuals still maintained lethal toxin-neutralizing serum antibody titers out to 112 d postvaccination. Vaccination responses were variable but effective to some degree in all white-tailed deer.

Evaluation of a live attenuated vaccine against Edwardsiella piscicida by 16S rRNA sequencing

A complex and dynamic community of microorganisms is attached to the mucosal surface of the fish gut. Gut microbes play important roles in fish metabolism and immunity. Edwardsiella piscicida infection of turbot causes Edwardsiellosis, and vaccination is an effective method to prevent and control aquaculture diseases. Here, intraperitoneal vaccination by E. piscicida 10Δ, a live attenuated vaccine candidate, significantly upregulated the expression of immune response-related genes in the turbot spleen and enhanced the serum antibody titers of IgM. 16S rRNA amplicon sequencing revealed that the vaccination of E. piscicida 10Δ slightly reduced the relative abundance of intestinal microbiota in turbot. Meanwhile, E. piscicida 10Δ potentially conferred the intestinal microbiota metabolic capacity associated with carbohydrate metabolism, while hypothetically impaired their metabolic capacity related to fatty acid degradation and amino acid metabolism. Collectively, E. piscicida 10Δ can effectively stimulate the host immune responses and has no apparent influence on the relative abundance of intestinal microbiota, which can thus be considered as a potentially safe live attenuated vaccine.

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 &lt; 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 &lt; 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.