Specific Serum Antibody Titers Research Articles

MIL-53(Al)–oil/water emulsion composite as an adjuvant promotes immune responses to an inactivated pseudorabies virus vaccine in mice and pigs

Although vaccination with inactivated vaccines is a popular preventive method against pseudorabies virus (PRV) infection, inactivated vaccines have poor protection efficiency because of their weak immunogenicity. The development of an effective adjuvant is urgently needed to improve the efficacy of inactivated PRV vaccines. In this study, a promising nanocomposite adjuvant named as MIL@A–SW01–C was developed by combining polyacrylic acid-coated metal–organic framework MIL-53(Al) (MIL@A) and squalene (oil)-in-water emulsion (SW01) and then mixing it with a carbomer solution. One part of the MIL@A was loaded onto the oil/water interface of SW01 emulsion via hydrophobic interaction and coordination, while another part was dispersed in the continuous water phase using carbomer. MIL@A–SW01–C showed good biocompatibility, high PRV (antigen)-loading capability, and sustained antigen release. Furthermore, the MIL@A–SW01–C adjuvanted PRV vaccine induced high specific serum antibody titers, increased splenocyte proliferation and cytokine secretion, and a more balanced Th1/Th2 immune response compared with commercial adjuvants, such as alum and biphasic 201. In the mouse challenge experiment, two- and one-shot vaccinations resulted in survival rates of 73.3 % and 86.7 %, respectively. After one-shot vaccination, the host animal pigs were also challenged with wild PRV. A protection rate of 100 % was achieved, which was much higher than that observed with commercial adjuvants. This study not only establishes the superiority of MIL@A–SW01–C composite nanoadjuvant for inactivated PRV vaccine in mice and pigs but also presents an effective method for developing promising nanoadjuvants. Statement of significanceWe have developed a nanocomposite of MIL-53(Al) and oil-in-water emulsion (MIL@A–SW01–C) as a promising adjuvant for the inactivated PRV vaccines. MIL@A–SW01–C has good biocompatibility, high PRV (antigen) loading capability, and prolonged antigen release. The developed nanoadjuvant induced much higher specific IgG antibody titers, increased splenocyte proliferation and cytokine secretion, and a more balanced Th1/Th2 immune response than commercial adjuvants alum and biphasic 201. In mouse challenge experiments, survival rates of 73.3 % and 86.7 % were achieved from two-shot and one-shot vaccinations, respectively. At the same time, a protection rate of 100 % was achieved with the host animal pigs challenged with wild PRV.

Effect of Aging on the Immune Response to Core Vaccines in Senior and Geriatric Dogs.

Elderly dogs are steadily increasing worldwide as well as veterinarians' and owners' interest in their health and wellness. Aging is not a disease, but a combination of changes negatively affecting the organism in general and the immune system in particular, resulting in a decline in protection over time. The aim of this study was to measure the specific serum antibody titers against the main dangerous and widespread viral diseases preventable by core vaccinations in senior and geriatric dogs using the in-practice test VacciCheck. A cohort of three hundred fifty elderly dogs was analyzed for Protective Antibody Titers (PATs) against CPV-2, CDV and CAdV-1. The age ranged from 5 to 19 years, with two hundred fifty-eight seniors (73.7%) and ninety-two geriatrics (26.3%), and 97.4% of them were vaccinated at least once in their lives. More than half of the entire study population (52.9%) had PATs simultaneously for all three diseases, with 80.5% seniors and 19.5% geriatrics. Specific PATs were found in 88.6% of aging dogs for CPV-2, 82.3% for CadV-1 and 66.0% for CDV, demonstrating that unprotected aging dogs represent a minority. Unexpectedly, the larger elderly dogs resulted as more protected than smaller ones for CPV-2. Protection then decreases over time, with geriatric dogs less protected than senior ones. Veterinary practitioners should therefore always consider whether to maintain core vaccinations in aging dogs as in adults on a three-year basis or opt instead for closer boosters (every 1 or 2 years). PATs for core vaccines could then represent a good biomarker of protection and their titration could become a standard of care, especially in such a sensitive period of the dogs' life.

Population immunity in residents of the Kaliningrad region to current antigenic variants of influenza viruses over 2018-2021

The article presents the results of population immunity assessment in residents of the Kaliningrad region to current antigenic variants of influenza viruses over the period of 2018 to 2021. To assess spectrum of influenza types circulating in Kaliningrad region, the real-time PCR method was used using AmpliSense reagent kits. The biological material for the study was obtained from oropharyngeal swabs from the persons who applied to polyclinics with inflammatory diseases of upper respiratory tract, or underwent treatment at the out- or inpatient basis in a healthcare facilities of Kaliningrad region. Humoral immunity was assessed by testing blood sera obtained from healthy residents of Kaliningrad region during periodic prophylactic examinations at the city and regional polyclinics. The study of residents covered all age groups. For the period of 2018-2021, more than 14,000 studies have been carried out. Determination of specific serum antibody titers was carried out by staging the hemagglutination suppression reaction using local influenza antigens (LLC PPDP, St. Petersburg). Antibody titers of 1/40 and higher were considered sufficient to reduce the risk of disease by 50%. During the study period, 2165 cases of influenza were confirmed in the region by laboratory tests. Over the study period, the A(H1N1) pdm serotype proved to be the major strain causing influenza, its proportion reached 57.5%. However, along with A(H1N1) pdm, a significant contribution was also made the A(H3N2) strain to the epidemic process, being the etiological cause of influenza infection in 2019 (42.2%), type B influenza strains being actual in 2020 (42.5%). Over the period of 2018-2021, 420 samples of blood sera from vaccinated and non-vaccinated individuals were tested for specific antibodies. The sera were taken 1-2 months after vaccination and between epidemic rises of influenza (April-May). In vaccinated individuals, the antibody titer was protective in 58.3-64.5%. In this group of persons, the titer sufficient to produce immunity was maintained over the spring/summer period. Among those persons who refused vaccination, a protective antibody titer in the pre-epidemic period was noted in 41.2% of the examined, and during the off-season it was detected in 37.4% of the volunteers. Thus, the A(H1N1) pdm strain was the main etiological factor of influenza in Kaliningrad Region in 2018-2021. The protective level of antibodies in vaccinated population over the period preceding the epidemic peak, was observed 30% more often than in unvaccinated individuals. High incidence of influenza B strains noted in 2020 appears to require a change of specific vaccine preparation.

Development and Evaluation of a Rapid Neutralizing Antibody Assay for COVID-19 Vaccination.

SARS-CoV-2 neutralizing antibodies have excellent application prospects in the prevention and treatment of COVID-19. This study established a competitive colloidal gold immunochromatography assay (GICA) to detect neutralizing antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 in postvaccination serum. The sensitivity, stability, and specificity of GICA were evaluated using neutralizing antibody solution reference material and positive serum. The consistency and correlation between GICA, pseudovirus neutralization (PN) assay, and ELISA were compared. Consistency analysis of serum neutralizing antibody and specific IgG antibody titers was conducted, and changes in neutralizing antibodies and specific IgG antibodies in serum after inoculation with the homologous booster inactivated vaccine and recombinant vaccine were noted. The sensitivity of the reagent was 20.66 IU/L, and the specificity was 100%. There was a strong consistency and correlation between GICA and PN (κ = 0.886, n = 165; r = 0.918, P < 0.001). The correlation coefficient of serum anti-RBD antibody and specific IgG antibody titers was 0.5253 (P < 0.001). The specific IgG antibody titers in serum after (W4) inoculation with homologous booster inactivated vaccine were 10.80 (S/CO).The anti-RBD antibody titers were 28.33. The anti-RBD omicron variant (B.1.1.529) antibody titers were 11.67. After inoculation with the recombinant vaccine, the specific IgG antibody titers in the serum of W4 were 10.68. The serum anti-RBD antibody titers of W4 were 103.30. The serum anti-RBD omicron variant (B.1.1.529) antibody titers of W4 were 56.67. Therefore, vaccination of the third dose of the homologous booster inactivated vaccine and recombinant vaccine can enhance the level of neutralizing antibodies against the omicron variant (B.1.1.529). This study demonstrates that a GICA kit for neutralizing antibodies against the RBD of SARS-CoV-2 can be used for COVID-19 vaccine evaluation. Changes in titers enable long-term monitoring of a population’s immunity and guide interventions when their immunity declines.

Ovine Pasteurellosis Vaccine: Assessment of the Protective Antibody Titer and Recognition of the Prevailing Serotypes.

Sheep husbandry is considered one of the most important activities in the socio-economic development in the Middle East region, especially in Iraq and Islamic Republic of Iran (IRI). Therefore this study was designed to evaluate the level of ovine pasteurellosis vaccine protective antibody titer and identification of the prevailing serotypes in Iraq (Basrah, Baghdad, Tikrit, Mosul, Erbil). The vaccine was made from pasteurella multosida Bio-type A and the serotypes of Mannheimia haemolytica. This investigation was performed from September 2021 to January 2022, in Iraq. Sheep blood sera samples were obtained from control unvaccinated and vaccinated sheep after 14, 21 and 28 days post vaccination. The results showed that out of 319 sheep blood sera samples which were evaluated using indirect Haemagglutination (IHA) test to detect Mannheimia haemolytica serotypes, the high prevalence (100 %) of M. haemolytica A2 was found in all the five study regions area, while 96.5 % was M. haemolytica A7 and 88.1 % was M. haemolytica A1. The level of antibody titer was measured by specific serum antibody titer of pasteurella multosida Bio-type A. The results revealed that out of 268 vaccinated blood sera samples the overall antibody titer were 12 (3.8 %), 16 (5%) and 17 (5.3 %) for protective antibody titer of 1:160, 1:80 and 1:40 respectively and for antibody titer of 1:20 were 15 (4.7%) and for antibody titer of 1:10 were 17 (5.3 %), whereas the antibody titer in the control group was 4 (7.8 %). The result of this study indicated that the vaccine administered has limited protective power against pasteurella multocida Bio-type A which lead to researchers for further study on identification of specific strain of pasteurella multosida and development of multivalent vaccine including the most prevalent pasteurella serotypes.

Immunogenicity of Multi-Target Chimeric RHDV Virus-Like Particles Delivering Foreign B-Cell Epitopes.

The rabbit hemorrhagic disease virus (RHDV) vaccine platform is a nanoparticle composed of 180 copies of the viral capsid protein, VP60, self-assembled into virus-like particles (VLPs). RHDV VLPs are able to accept the simultaneous incorporation of target epitopes at different insertion sites. The resulting chimeric RHDV VLPs displaying immunogenic foreign antigens have been shown to induce specific protective immune responses against inserted heterologous T-cytotoxic and B-cell epitopes in the mouse and pig models. In this study, we explored whether RHDV-based engineered VLPs can be developed as efficient multivalent vaccines co-delivering different foreign B-cell antigens. We generated bivalent chimeric RHDV VLPs displaying two model B-cell epitopes at different surface-exposed insertion sites, as well as the corresponding monovalent chimeric VLPs. The immunogenic potential of the bivalent chimeric VLPs versus the monovalent constructs was assessed in the mouse model. We found that the bivalent chimeric VLPs elicited a strong and balanced antibody response towards the two target epitopes tested, although slight reductions were observed in the levels of specific serum antibody titers induced by bivalent chimeric VLPs as compared with the corresponding monovalent constructs. These results suggest that RHDV VLPs could represent a promising platform for the development of efficient multivalent vaccines.

Potential Efficacy of Chitosan-Poly (Lactide-Co-Glycolide)-Encapsulated Trivalent Immersion Vaccine in Olive Flounder (Paralichthys olivaceus) Against Viral Hemorrhagic Septicemia Virus, Streptococcus parauberis Serotype I, and Miamiensis avidus (Scuticociliate).

Olive flounder (Paralichthys olivaceus) is the most valuable aquaculture species in Korea, corresponding to ~60% of its total production. However, infectious diseases often break out among farmed flounders, causing high mortality and substantial economic losses. Although some deleterious pathogens, such as Vibrio spp. and Streptococcus iniae, have been eradicated or contained over the years through vaccination and proper health management, the current disease status of Korean flounder shows that the viral hemorrhagic septicemia virus (VHSV), Streptococcus parauberis, and Miamiensis avidus are causing serious disease problem in recent years. Furthermore, these three pathogens have differing optimal temperature and can attack young fingerlings and mature fish throughout the year-round culture cycle. In this context, we developed a chitosan-poly(lactide-co-glycolide) (PLGA)-encapsulated trivalent vaccine containing formalin-killed VHSV, S. parauberis serotype-I, and M. avidus and administered it to olive flounder fingerlings by immersion route using a prime-boost strategy. At 35 days post-initial vaccination, three separate challenge experiments were conducted via intraperitoneal injection with the three targeted pathogens at their respective optimal temperature. The relative percentages of survival were 66.63%, 53.3%, and 66.75% in the group immunized against VHSV, S. parauberis serotype-I, and M. avidus, respectively, compared to the non-vaccinated challenge (NVC) control group. The immunized fish also demonstrated significantly (p < 0.05) higher specific antibody titers in serum and higher transcript levels of Ig genes in the mucosal and systemic tissues than those of NVC control fish. Furthermore, the study showed significant (p < 0.05) upregulation of various immune genes in the vaccinated fish, suggesting induction of strong protective immune response, ultimately leading to improved survival against the three pathogens. Thus, the formulated mucosal vaccine can be an effective prophylactic measure against VHS, streptococcosis, and scuticociliatosis diseases in olive flounder.

Establishment of a rare minnow (Gobiocypris rarus) model for evaluation of experimental vaccines against a disease induced by grass carp reovirus genotype II

Vaccination is the most effective way to control the grass carp haemorrhagic disease (GCHD) with the primary pathogen grass carp reovirus genotype II (GCRV-II). However, due to the large difference in breeding conditions and unclear genetic background of grass carp, the results of the experiment were not reliable, which further hinders the effective prevention and control of GCHD. The rare minnow (Gobiocypris rarus) is highly sensitive to GCRV. Its small size, easy feeding, transparent egg membrane, and annual spawning are in line with the necessary conditions for an experimental aquatic animals culture object. In this study, immunogenicity and protective effects of attenuated and inactivated viruses for grass carp and rare minnow were evaluated in parallel. The expression of immune-related genes increased statistically significant after immunization. With the rise of specific serum antibody titers, the results of rare minnow and grass carp were consistent. In addition, there was no significant residue of adjuvant observed in both fish species injected with an adjuvanted and inactivated virus. Challenge of immunized grass carp and rare minnow with the isolate HuNan1307 resulted in protection rates of 95.8% and 92.6% for attenuated virus, 81.4% and 77.7% for inactivated virus, respectively, as well as the viral load changed consistently. The results indicated that rare minnow can be used as a model for evaluation of experimental vaccines against GCHD.

Development of Aeromonas salmonicida subsp. masoucida vaccine in turbot and evaluation of protection efficacy under field conditions

Aeromonas salmonicida is a global fish pathogen that can infect a series of fish species. Vaccination by commercial vaccine has been proved to be an effective method to control this disease in Atlantic salmon. However, commercial vaccines used to protect against A. salmonicida subsp. salmonicida infection are not necessarily effective against infections by other subspecies. Given increasing number of infections by A. salmonicida subsp. masoucida in turbot (Scophthalmus maximus) farming in China, we developed an A. salmonicida subsp. masoucida inactivated vaccine for turbot in the present research. Using a previously isolated pathogenic strain RZ6S-1, a water-based vaccine and an oil-based Marcol 52 emulsified vaccine were developed, and first evaluated under laboratory conditions. Results showed that the relative percent of survival (RPS) and specific serum antibody titers of the fish vaccinated by the emulsified vaccine were significantly higher than that of those vaccinated by the water-based vaccine at 4 weeks post vaccination. Under field conditions, turbot were protected for 12 weeks and 24 weeks post vaccination by emulsified vaccine, with the challenged RPS reaching 84.66 ± 6.39% and 84.54 ± 5.93%, respectively. The specific antibody titers against A. salmonicida subsp. masoucida in the vaccinated fish could even be detected at 24 weeks post vaccination. In comparison, cumulative mortality of the control fish (12.96%) was higher than that of the vaccinated fish (2.48%), with more fish died of natural infection by A. salmonicida (221 vs. 17). Cutaneous nodules, possibly caused by chronic infection by A. salmonicida, were found in 23 of 30 randomly selected fish in the control pond at 24 weeks post vaccination, in contrast to only 1 of 30 in the vaccinated pond. More infections caused by Edwardsiella piscicida and scuticociliate were also observed in the control pond, indicating that the cutaneous nodules may facilitate the infection by other pathogens and parasites. Additionally, the fish weight in the vaccinated pond was significantly higher than that in the control pond, both at 12 weeks and 24 weeks post vaccination. These results indicated that the A. salmonicida emulsified vaccine can protect turbot for at least 24 weeks without severe side-effects on the fish growth under field conditions, and can also protect fish from chronic infection, which in turn reduces the infection probability by other pathogens or parasites. In conclusion, the present study indicates that the developed vaccine protects turbot from A. salmonicida subsp. masoucida infection under farming conditions.

Virus-specific memory T cell responses unmasked by immune checkpoint blockade cause hepatitis

Treatment of advanced melanoma with combined PD-1/CTLA-4 blockade commonly causes serious immune-mediated complications. Here, we identify a subset of patients predisposed to immune checkpoint blockade-related hepatitis who are distinguished by chronic expansion of effector memory CD4+ T cells (TEM cells). Pre-therapy CD4+ TEM cell expansion occurs primarily during autumn or winter in patients with metastatic disease and high cytomegalovirus (CMV)-specific serum antibody titres. These clinical features implicate metastasis-dependent, compartmentalised CMV reactivation as the cause of CD4+ TEM expansion. Pre-therapy CD4+ TEM expansion predicts hepatitis in CMV-seropositive patients, opening possibilities for avoidance or prevention. 3 of 4 patients with pre-treatment CD4+ TEM expansion who received αPD-1 monotherapy instead of αPD-1/αCTLA-4 therapy remained hepatitis-free. 4 of 4 patients with baseline CD4+ TEM expansion given prophylactic valganciclovir and αPD-1/αCTLA-4 therapy remained hepatitis-free. Our findings exemplify how pathogen exposure can shape clinical reactions after cancer therapy and how this insight leads to therapeutic innovations.

Astragalus Polysaccharides Enhance the Immune Response to Newcastle Disease Virus Vaccination in Chickens

This study was conducted to evaluated the effects of Astragalus polysaccharide on immune responses of chickens immunized with NDV Lasota vaccine. One hundred chickens at one-day-old( Ross breed) were brought , on five day of age, the average maternal serum Abs was measured by hemaglutination inhibition (HI) test and the titer was 3.43 log, and then divided into five equal groups in each group twenty chicks and on day 10 of age the Astragalus polysaccharide high concentration (APSH) group were given 0.5 ml at 400mg /100ml , the Astragalus polysaccharide medium concentration (APSM )group were given 0.5 ml at 200mg /100ml, the Astragalus polysaccharide low concentration (APSL) group were given 0.5 ml at 100mg /100ml , Vaccine control (VC) group were given 0.5 ml normal saline only, Negative control (NC ) group were given normal saline only , all groups orally administrated for four days. At 14 day of age, all chickens with the exception of NC group , were vaccinated with ND Lasota by Intraocular and Intranasal methods. Four blood sample from all groups were aspirated from jugular vein at 0h (before vaccination),6h,12h and 24h(after vaccination ) for determine of Chicken IL-6(Interleukin 6) by RT-PCR. On day 20and 30 of age after vaccination , three chicken were sampled randomly from each group to detect specific serum Antibody titer of NDV by HI test. On days 1,7,14,21after vaccination, four serum Samples from the same of chicken to determines IgA level by sandwich ELISA test. The cellular and humeral response including the production of cytokine IL-6 ( by RT-PCR test) were measured on 0h(before vaccination),6h,12h and 24h( after vaccination )and IgA antibody ( by ELISA test ) were measured on 1d,7d,14d,and 21days after vaccination and serum antibody titer Specific to NDV( by HI test ) were measured at age 20, and 30 days after vaccination evaluated by series of experiments. Results revealed that all the polysaccharide groups were numerically increased in antibody levels, the expression of IL-6and IgA level ,but three parameter were significant (𝑃 &lt; 0.05) in the APSH group compared to corresponding (VC) vaccinated group and( NC) non –vaccinated group. These results suggest that orally administered APS could significantly enhance the efficacy of NDV vaccination and has important implications for the further use of APS as a novel adjuvant.

Astragalus Polysaccharides Enhance the Immune Response to Newcastle Disease Virus Vaccination in Chickens

This study was conducted to evaluated the effects of Astragalus polysaccharide on immune responses of chickens immunized with NDV Lasota vaccine. One hundred chickens at one-day-old( Ross breed) were brought , on five day of age, the average maternal serum Abs was measured by hemaglutination inhibition (HI) test and the titer was 3.43 log, and then divided into five equal groups in each group twenty chicks and on day 10 of age the Astragalus polysaccharide high concentration (APSH) group were given 0.5 ml at 400mg /100ml , the Astragalus polysaccharide medium concentration (APSM )group were given 0.5 ml at 200mg /100ml, the Astragalus polysaccharide low concentration (APSL) group were given 0.5 ml at 100mg /100ml , Vaccine control (VC) group were given 0.5 ml normal saline only, Negative control (NC ) group were given normal saline only , all groups orally administrated for four days. At 14 day of age, all chickens with the exception of NC group , were vaccinated with ND Lasota by Intraocular and Intranasal methods. Four blood sample from all groups were aspirated from jugular vein at 0h (before vaccination),6h,12h and 24h(after vaccination ) for determine of Chicken IL-6(Interleukin 6) by RT-PCR. On day 20and 30 of age after vaccination , three chicken were sampled randomly from each group to detect specific serum Antibody titer of NDV by HI test. On days 1,7,14,21after vaccination, four serum Samples from the same of chicken to determines IgA level by sandwich ELISA test. The cellular and humeral response including the production of cytokine IL-6 ( by RT-PCR test) were measured on 0h(before vaccination),6h,12h and 24h( after vaccination )and IgA antibody ( by ELISA test ) were measured on 1d,7d,14d,and 21days after vaccination and serum antibody titer Specific to NDV( by HI test ) were measured at age 20, and 30 days after vaccination evaluated by series of experiments. Results revealed that all the polysaccharide groups were numerically increased in antibody levels, the expression of IL-6and IgA level ,but three parameter were significant (𝑃 &lt; 0.05) in the APSH group compared to corresponding (VC) vaccinated group and( NC) non –vaccinated group. These results suggest that orally administered APS could significantly enhance the efficacy of NDV vaccination and has important implications for the further use of APS as a novel adjuvant.

Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19

BackgroundWhereas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody tests are increasingly being used to estimate the prevalence of SARS-CoV-2 infection, the determinants of these antibody responses remain unclear.ObjectivesOur aim was to evaluate systemic and mucosal antibody responses toward SARS-CoV-2 in mild versus severe coronavirus disease 2019 (COVID-19) cases.MethodsUsing immunoassays specific for SARS-CoV-2 spike proteins, we determined SARS-CoV-2–specific IgA and IgG in sera and mucosal fluids of 2 cohorts, including SARS-CoV-2 PCR-positive patients (n = 64) and PCR-positive and PCR-negtive health care workers (n = 109).ResultsSARS-CoV-2–specific serum IgA titers in patients with mild COVID-19 were often transiently positive, whereas serum IgG titers remained negative or became positive 12 to 14 days after symptom onset. Conversely, patients with severe COVID-19 showed a highly significant increase of SARS-CoV-2–specific serum IgA and IgG titers after symptom onset. Very high titers of SARS-CoV-2–specific serum IgA were correlated with severe acute respiratory distress syndrome. Interestingly, some health care workers with negative SARS-CoV-2–specific serum antibody titers showed SARS-CoV-2–specific IgA in mucosal fluids with virus-neutralizing capacity in some cases. SARS-CoV-2–specific IgA titers in nasal fluids were inversely correlated with age.ConclusionsSystemic antibody production against SARS-CoV-2 develops mainly in patients with severe COVID-19, with very high IgA titers seen in patients with severe acute respiratory distress syndrome, whereas mild disease may be associated with transient production of SARS-CoV-2–specific antibodies but may stimulate mucosal SARS-CoV-2–specific IgA secretion.

Prenatal exposure to DDT and pyrethroids and humoral response to vaccines among South African children from an area sprayed for malaria control

OPS 60: Social factors and environmental health across the world, Room 210, Floor 2, August 27, 2019, 1:30 PM - 3:00 PM Background/Aim: Animals studies strongly suggest that exposure to insecticides such as DDT and pyrethroids may inhibit immune response to vaccines. However, few human studies have investigated this question and none have done so in communities where insecticides are used to control malaria as part of Indoor Residual Spraying programs. These communities experience high exposure to insecticides and may be particularly susceptible to their toxic effects due to poverty, malnutrition and poor health. Our objective was thus to evaluate whether prenatal exposure to DDT and pyrethroids was associated with reduced immune response to vaccines at age 3.5 and 5 years among South African children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) birth cohort study. Methods: Between August 2012 and December 2013, we enrolled 752 women when they presented for delivery at Tshilidzini hospital in the city of Thohoyandou. We collected urine and blood samples at delivery for the measurement of pyrethroid metabolites and DDT via gas chromatography-mass spectrometry, respectively. At age 3.5 and 5 years, we measured measles, tetanus and Haemophilus influenzae b (Hib)-specific antibody titers in serum via enzyme-linked immunosorbent assay (ELISA). Results: Percentages of fully-vaccinated children with antibody titers below protective levels were 5.6% for measles, 31.1% for tetanus and 29.1% for Hib. Prenatal exposure to pyrethroids was associated with elevated risks of low measles (but not tetanus and Hib) antibody titers at 3.5 years. Each 10-fold increase in maternal urinary concentrations of 3-PBA, trans-DCCA and cis-DCCA was associated with relative risks of 1.85 (95%CI=0.98, 3.49), 1.84 (95%CI=1.09, 3.09) and 2.43 (95%CI=1.38, 4.29), respectively. No associations were found with DDT and DDE. Associations with antibody titers at age 5 will also be presented. Conclusion: Results suggest that prenatal exposure to pyrethroids may inhibit immune response to vaccines among South African children.

Intranasal immunization of cocktail/fusion protein containing Tir along with ΔG active fragment of Zot as mucosal adjuvant confers enhanced immunogenicity and reduces E. coli O157:H7 shedding in mice

Ruminants are the major reservoirs of Escherichia coli O157:H7 and its fecal shedding mainly act as a source of entry of this pathogen into the human food chain. In humans, E. coli O157:H7 infection causes diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. Intimate adherence of E. coli O157:H7 is mediated by Translocated intimin receptor (Tir) to which intimin binds in the host cell. Since E. coli O157:H7 colonizes intestinal epithelium, the mucosal vaccine has a potential to prevent its colonization. Zonula occludens toxin (Zot) of Vibrio cholerae transiently, reversibly alters epithelial tight junction structure to increase mucosal permeability of macromolecules via paracellular route. The C-terminal region of Zot (ΔG) responsible for this function could be used for mucosal antigen delivery. Therefore, we employed individual (Tir), cocktail (ΔG + Tir), fusion protein (ΔG-Tir) and assessed the efficacy of its intranasal immunization on immunogenicity and fecal shedding of E. coli O157:H7 in streptomycin treated mouse model. Compared to control, ΔG + Tir, ΔG-Tir immunized mice elicited significant antigen specific antibody titers in serum (IgG, IgA) and feces (IgA), whereas Tir immunized mice induced only serum IgG titer. Cytokine analysis revealed mixed Th1/Th2 type immune response in case of ΔG + Tir, ΔG-Tir group while that of Tir group was solely Th2 type. Tir, ΔG + Tir and ΔG-Tir immunized mice showed reduction in shedding of E. coli O157:H7 compared to control group. However, ΔG-Tir immunized group performed better than ΔG + Tir, Tir group in reducing fecal shedding. Overall, our results demonstrate that intranasal immunization of ΔG-Tir induces effective systemic, mucosal, cellular immune responses and represents a promising mucosal subunit vaccine to prevent E. coli O157:H7 colonization.

The antibody response in the bovine mammary gland is influenced by the adjuvant and the site of subcutaneous vaccination

Intramammary infections in cattle resulting in mastitis have detrimental effects on cows’ well-being, lifespan and milk production. In the host defense against S. aureus mastitis antibodies are thought to play an important role. To explore potential ways to increase antibody titers in the bovine mammary gland the effects of various adjuvants on the magnitude, isotype, and neutralizing capacity of antibodies produced following subcutaneous vaccine administration at different immunization sites were analyzed. In this study, α-toxoid was used as a model antigen and formulated in three different alum-based adjuvants: Alum–Saponin, Alum–Oil, and Alum–Saponin–Oil. Vaccines were administered near the suspensory ligament of the udder or in the lateral triangular area of the neck. At both immunization sites, immunization with α-toxoid in Alum–Saponin–Oil resulted in higher specific antibody titers in milk and serum as compared with Alum–Oil and Alum–Saponin, without favoring an IgG1, IgG2, or IgA response. Furthermore, the neutralizing capacity of milk serum and serum following immunization near the udder and in the neck was higher when Alum–Saponin–Oil was used as adjuvant compared with Alum–Oil and Alum–Saponin. Prime immunizations near the udder effectively increased both antibody isotype titers and neutralization titers, while prime plus boost immunizations were required to induce similar effects following immunization in the neck. Results indicate that subcutaneous administration of an Alum–Saponin–Oil based vaccine near the udder could be further explored for the development of a one-shot vaccination strategy to efficiently increase intramammary antibody responses.

Recombinant chicken interleukin-7 as a potent adjuvant increases the immunogenicity and protection of inactivated infectious bursal disease vaccine

Our previous work showed that a plasmid-based chicken interleukin-7 (chIL-7) gene expression vector possessed potent adjuvant activity for a VP2 DNA vaccine against chicken infectious bursal disease virus (IBDV). Whether recombinant chIL-7 prepared in procaryotic expression system has the adjuvant activity for inactivated IBDV vaccine remains unknown. Here, we prepared recombinant chIL-7 using an E. coli expression system and analyzed its adjuvant activity for the inactivated IBDV vaccine. The results show that the recombinant chIL-7 was successfully prepared in E. coli using the pET20b vector, which possessed biological activity to stimulate mouse B lymphocyte proliferation. Co-administration of the chIL-7 with inactivated IBDV vaccine significantly increased specific serum antibody titers against IBDV, enhanced lymphocyte proliferation and IFN-γ and IL-4 productions, and increased protection against virulent IBDV infection.

Immunogenicity of recombinant Omp16 protein of Pasteurella multocida B:2 in mouse model

Bacterial peptidoglycan-associated lipoproteins (PAL) are potential targets for the development of diagnostics/subunit vaccines for infectious diseases. Most commonly prevalent Omp16 lipoprotein is absolutely conserved among Pasteurella multocida strains, which are involved in multiple infectious diseases of livestock worldwide. In the present study, we cloned omp16 gene encoding for mature Omp16 of P. multocida B:2 strain P52 and overexpressed as a fusion protein in Escherichia coli. Mice immunized with purified recombinant non-lipidated Omp16 fusion protein (~32 kDa) resulted in elicitation of significant antigen specific serum antibody titres (total IgG and subtypes). A more pronounced increase in Th2 response (IgG1) was noticed. The study indicated the potential possibilities to use lipidated recombinant Omp16 protein in developing a composite subunit vaccine along with suitable adjuvant for haemorrhagic septicaemia/ pasteurellosis in livestock.

Chicken IL-7 as a potent adjuvant enhances IBDV VP2 DNA vaccine immunogenicity and protective efficacy

Our previous work has demonstrated that the mammalian interleukin-7 (IL-7) gene can enhance the immunogenicity of DNA vaccine. Whether chicken IL-7 (chIL-7) possesses the ability to enhance the immunogenicity of VP2 DNA vaccine of infectious bursal disease virus (IBDV) remained unknown. To investigate this, we constructed a VP2 antigenic region (VP2366) gene and chIL-7 gene vectors, co-immunized chicken with these vectors and analyzed the effects of the chIL-7 gene on VP2366 gene immunogenicity. Results showed that co-administrated chIL-7 gene with VP2 DNA vaccine significantly increased specific serum antibody titers against IBDV, and enhanced lymphocyte proliferation and IFN-γ and IL-4 productions. More importantly, chIL-7 gene significantly increased VP2366 gene-induced protection against virulent IBDV infection, indicating that the chIL-7 gene possessed the capacity to enhance VP2366 DNA vaccine immunogenicity, and therefore might function as a novel adjuvant for IBDV VP2 DNA vaccine. Mechanically, chIL-7 could stimulate the common cytokine receptor γ chain (γc) expressions in vitro and in vivo, which might be involved in chIL-7 enhancement of the immunogenicity of VP2 DNA vaccine.

Expression and characterization of tissue inhibitor of metalloproteinase 4 from complex canine mammary carcinomas

ABSTRACTAll four members of the tissue inhibitors of metalloproteinase (TIMP) family have been reported to be over-expressed in breast cancer cells in vitro. Dysregulation of TIMP-4 expression predicts poor prognosis in cancers. The present study evaluated the association of the expression levels of TIMP-4 with mammary tumor development in dogs, measured by real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Mammary tissue samples were collected from healthy canine mammary gland and from tumor subjects. TIMP-4 expression was found to be upregulated (5.856 times) in complex canine mammary carcinomas. Also, TIMP-4 mature peptide was expressed heterologously in E. coli. The recombinant protein was purified by Ni- NTA affinity chromatography and further confirmed by western blotting. The rTIMP-4 was found to be functionally active and could inhibit matrix metalloproteinase 11(MMP-11) activity. Immunization of mice with rTIMP-4 resulted in increased antigen specific serum antibody titer, and this serum could be suitably used to detect and quantify the protein in sera of dogs with mammary tumors. TIMP-4 could act as a marker of canine mammary tumors. To the best of our knowledge, this is the first report of heterologous expression of TIMP-4 from complex canine mammary carcinomas.