Evaluation Of Humoral Immune Response Research Articles

Evaluation of Humoral Immune Response in COVID-19 Patients- A Comparative Study

Background: The novel coronavirus SARS-CoV-2 is a newly emerging virus. Positive detection of SARS-CoV-2 RNA by RT-PCR has been used to confirm SARS-CoV-2 infection. Recently positive detection of IgG and IgM antibodies specific to SARS-CoV-2 has also been recognized as deterministic evidence for confirmed SARS-CoV-2 infection. The antibody response in COVID-19 patient remains largely unknown, and the clinical values of antibody testing have not been fully demonstrated. Objective: To better clarify the humoral immune response during SARS-CoV-2 infection. Methods: This cross sectional study was carried out on 200 RT-PCR confirmed COVID-19 cases. For better evaluation of antibody response, patients were divided into two groups, group I and group II, each consisting of 100 persons. Results: Out of a total 200 cases antibody was detected in 104(52%) cases and antibody not detected in 96(48%) cases. Out of 104 seropositive cases only IgG was detected in 69.2% cases, only IgM in 10.6% cases and both IgG, IgM in 20.2% cases.In group I seropositivity was 68%. IgG, IgM and both IgG, IgM positivity were 58.8%, 14.7% and 26.5% respectively. In group II seropositivity was 36 %. Positivity for IgG, IgM and both IgG, IgM were 88.9%, 2.8% and 8.3% respectively. Conclusion: As we learn more about the long-term implications of COVID-19 on recovered individuals, antibody tests can be used to increase this understanding of the immune system response to SARS-CoV-2, quantify the magnitude of the COVID-19 outbreak and effectively manage patients. JAFMC Bangladesh, Vol 19, No 2 (December) 2023: 3-6

Gamma Irradiated Pasteurella multocida Vaccine induces strong humoral immunity and protects rabbits from disease

Pasteurella multocida is affecting a multitude of animals and severely affects livestock production. Existing vaccines are mostly chemically inactivated and do not lead to wide protection. Irradiated vaccines are enjoying a renaissance and the concept of “replication defficient but metabolically active” vaccines was recently evaluated in several vaccine trials. P. multocida was isolated from the nasal swab, blood, and lung swab samples from infected rabbits. Gamma irradiation of P. multocida for inhibition of replication was evaluated at an optimized irradiation dose of 10 Kgy established. Four groups of rabbits were (mock) vaccinated with a commercial P. multocida vaccine and three irradiated formulations as liquid, lyophilized formulations with added Trehalose and lyophilized-Trehalose with an “activation” culturing the irradiated bacteria for 24 in broth. Evaluation of humoral immune response by ELISA showed that all three irradiated vaccines produced an effective, protective, and continued IgG serum level after vaccination and bacterial challenge. The IFN-γ expression is maintained at a normal level, within each individual group however, the lyophilized trehalose irradiated vaccine showed peak mean of IFN-γ titer at one week after booster dose (day 21) which was statistically significant. Cumulatively, the results of this study show that gamma-irradiated P. multocida vaccines are safe and protect rabbits against disease. Moreover, Rabbits’ immunization with the three irradiated formulations avoided adverse side effects as compared to commercial polyvalent vaccine, the body weight gain for the irradiated vaccine groups indicates less stress compared to the commercial polyvalent vaccine.

Evaluation of humoral immune response after yellow fever infection: an observational study on patients from the 2017-2018 sylvatic outbreak in Brazil.

Between 2016 and 2018, Brazil experienced major sylvatic yellow fever (YF) outbreaks that caused hundreds of casualties, with Minas Gerais (MG) being the most affected state. These outbreaks provided a unique opportunity to assess the immune response triggered by the wild-type (WT) yellow fever virus (YFV) in humans. The plaque reduction neutralization test (PRNT) is currently the standard method to assess the humoral immune response to YFV by measuring neutralizing antibodies (nAbs). The present study aimed to evaluate the humoral immune response of patients from the 2017-2018 sylvatic YF outbreak in MG with different disease outcomes by using PRNTs with a WT YFV strain, isolated from the 2017-2018 outbreak, and a vaccine YFV strain. Samples from naturally infected YF patients were tested, in comparison with healthy vaccinees. Results showed that both groups presented different levels of nAb against the WT and vaccine strains, and the levels of neutralization against the strains varied homotypically and heterotypically. Results based on the geometric mean titers (GMTs) suggest that the humoral immune response after a natural infection of YFV can reach higher levels than that induced by vaccination (GMT of patients against WT YFV compared to GMT of vaccinees, P < 0.0001). These findings suggest that the humoral immune responses triggered by the vaccine and WT strains of YFV are different, possibly due to genetic and antigenic differences between these viruses. Therefore, current means of assessing the immune response in naturally infected YF individuals and immunological surveillance methods in areas with intense viral circulation may need to be updated.IMPORTANCEYellow fever is a deadly febrile disease caused by the YFV. Despite the existence of effective vaccines, this disease still represents a public health concern worldwide. Much is known about the immune response against the vaccine strains of the YFV, but recent studies have shown that it differs from that induced by WT strains. The extent of this difference and the mechanisms behind it are still unclear. Thus, studies aimed to better understand the immune response against this virus are relevant and necessary. The present study evaluated levels of neutralizing antibodies of yellow fever patients from recent outbreaks in Brazil, in comparison with healthy vaccinees, using plaque reduction neutralization tests with WT and vaccine YFV strains. Results showed that the humoral immune response in naturally infected patients was higher than that induced by vaccination, thus providing new insights into the immune response triggered against these viruses.

Evaluation of humoral immune responses of experimental animals to the recombinant SARS-CoV-2 spike ectodomain with the ISCOM adjuvant

Scientific relevance. The use of recombinant antigens in vaccine production is limited because vaccines based on such antigens tend to have low immunogenicity. However, a COVID-19 vaccine that combines recombinant SARS-CoV-2 spike glycoprotein as its antigen and virus-like immune-stimulating complexes (ISCOMs) as its adjuvant (Nuvaxovid) induces a protective virus-neutralising response. The State Research Center of Virology and Biotechnology “Vector” (hereinafter, Vector) has developed the ISCOM adjuvant Matrix-V, which plays a key role in inducing virus-neutralising antibodies. Studying Matrix-V will provide for the wide use of recombinant antigens combined with this adjuvant in the development and production of novel Russian vaccines.Aim. This study aimed to evaluate the humoral immune responses of experimental animals to intramuscular injections of a complex combining the recombinant Wuhan-type SARS-CoV-2 spike RBD antigen and the virus-like ISCOM adjuvant containing Quillaja saponaria saponins.Materials and methods. The Matrix-V ISCOM adjuvant was produced using Vector’s proprietary technology, which involves cross-flow filtration through Sartorius VivaFlow cassettes. To determine the saponin and residual detergent concentrations in Matrix-V, the authors conducted high-performance liquid chromatography. Having produced the recombinant SARS-CoV-2 RBD antigen, the authors used electron microscopy to analyse the ultrastructure of the ISCOM–antigen complex. In the study of the ISCOM–antigen complex, 25 female Balb/c mice (5 groups) and 15 male and female outbred guinea pigs (3 groups) received two intramuscular injections with a 14-day interval. Serum tests relied on virus neutralisation (VN) and enzyme-linked immunosorbent assay (ELISA) methods and used antigens of 8 SARS-CoV-2 variants (State Collection of Viruses and Rickettsia, Vector). The authors used Statistica 10 to analyse the results.Results. Two injections of the SARS-CoV-2 RBD antigen (mice: 7 μg, guinea pigs: 1 μg) alone did not induce statistically significant virus-neutralising antibody responses, as shown by the VN results. Two injections of the SARS-CoV-2 RBD antigen (mice: 7 μg, guinea pigs: 1 μg) adjuvanted with Matrix-V (25 μg) resulted in geometric mean antibody titres of 1:83–1:178 (mice) and 1:174–1:587 (guinea pigs) in the VN tests with the Wuhan variant. One injection of the antigen (1 μg or 7 μg) with Matrix-V (25 μg) induced antibodies only in individual cases, as demonstrated by the VN and/or ELISA results. The most intensive immune response was observed in ELISA tests with the Delta variant after two injections of the Ecto-S-Wuhan (1 μg) and Matrix-V (25 μg) complex. Immune responses did not differ between the group that received two injections of the Ecto-S-Wuhan antigen (1 μg) without the ISCOM adjuvant and the negative control group (titres below 1:100; p=0.95). Two injections of the SARS-CoV-2 RBD antigen (7 μg) without the ISCOM adjuvant induced antibodies in mice (titres between 1:248 and 1:1477).Conclusions. Two intramuscular injections of the complex containing the recombinant SARS-CoV-2 RBD antigen and the Matrix-V ISCOM adjuvant induce virus-neutralising antibodies. The approach proposed by the authors has the potential for use in the development of immunobiological medicinal products to prevent and treat a wide range of infectious diseases.

Evaluation of humoral immune responses against C. perfringens epsilon toxin in Iranian sheep and goats after vaccination

Clostridium perfringens is a common cause of death in domestic animals worldwide. However, vaccination on a regular basis is an economically beneficial means for controlling clostridial contamination.The objective of the current investigation was to evaluate the humoral immune responses using iELISA in Iranian sheep and goats following the vaccination programs administered by the bacterin-toxoid polyvalent entrotoxemia vaccine. A total of one-hundred-and-twenty animals, consisting of sixty sheep and sixty goats, were randomly divided into three groups. These animals were vaccinated with clostridial vaccine on days 0 and 14 using two different dosages. Blood samples were collected on day zero, 15, 30, 45, 60, 75, and 90 following vaccination. The sera samples were then separated and antibody titers were measured using an in-house enzyme-linked immunosorbent assay (ELISA) against C. perfringens epsilon toxin. The titers of antibodies in sheep were notably higher than those in goats, particularly after receiving the booster dose. No statistically significant variations were identified in the immune responses of Iranian sheep and goat breeds. (p>0.05). Overall, the duration of the humoral immune response in goats upon administration of the clostridial vaccine was relatively brief, requiring multiple booster injections.

Evaluation of humoral immune response after ChAdOx1 nCoV-19 vaccination among health care workers.

We assessed the immunogenicity of ChAdOx1 nCoV-19 vaccination by evaluating the levels of SARS-CoV-2 IgG after vaccination and investigated the effect of diverse factors such as gender, age, and adverse reactions after vaccination. The study included a total of 1028 serum samples from 452 healthcare workers. SARS-CoV-2 IgG levels were assessed using the SARS-CoV-2 IgG II Quant assay. Participants completed a questionnaire regarding the intensity and duration of adverse reactions after vaccination. The seropositive rates after the first and second doses were 95.5% and 100%, respectively. The median antibody levels after the second dose showed a 4.2-fold increase compared with the first. Five months after the second dose, the median antibody levels decreased by 3.5-fold. The antibody levels in men were lower than those in women after the first dose and were higher after the second dose. There was no difference according to age groups after the first dose, but after the second dose, in subjects aged 50 and above, the rise in antibody levels was less than that in other age groups. The antibody levels among participants with moderate or severe symptoms were significantly higher than those among participants with mild symptoms after the first dose. There were no statistically significant differences according to the duration of symptoms. We could assume that different age groups and genders might have different immunogenicity following vaccination. The intensity of adverse symptoms was positively correlated with the antibody levels, implying that higher immunogenicity is related to the intensity of adverse symptoms after vaccination.

A comprehensive evaluation of humoral immune response to second and third SARS-CoV-2 mRNA vaccination in patients with malignant lymphoma.

More information is needed regarding the efficacy of SARS-CoV-2 mRNA vaccines in immunocompromised populations, including patients with malignant lymphoma. This study aimed to evaluate humoral responses to the second and third mRNA vaccine doses in 165 lymphoma patients by retrospective analysis of serum SARS-CoV-2 spike protein antibody (S-IgG) titers. Patients with S-IgG titers ≥ 300, 10-300, and ≤ 10 binding antibody units (BAU)/mL were defined as adequate responders, low responders, and non-responders, respectively. S-IgG titers > 10BAU/mL were considered to indicate seroconversion. After the second dose, 56%, 16%, and 28% of patients were adequate responders, low responders and non-responders, respectively. Multivariate analysis revealed that being an adequate responder after the second dose was associated with receiving the vaccine > 12months after last chemotherapy, total peripheral lymphocyte count of ≥ 1000/µL, estimated glomerular filtration rate of ≥ 50mL/min/1.73m2, and vaccine type (mRNA-1273). After the third dose, patients had significantly higher S-IgG titers and a greater proportion achieved seroconversion. With this third dose, 26% of second-dose non-responders achieved seroconversion and 68% of second-dose low responders became adequate responders. Subsequent SARS-CoV-2 mRNA vaccinations may elicit an immune response in immunocompromised patients who do not initially respond to vaccination.

Evaluation of humoral immune response in relation to COVID-19 severity over 1 year post-infection: critical cases higher humoral immune response than mild cases.

Coronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2. We investigated the antibody response against SARS-CoV-2 until 1 year after symptom onset. We collected 314 serum samples from 97 patients with COVID-19. Antibody responses were tested using an indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (ELISA), and plaque reduction neutralization test (PRNT) to detect specific neutralizing antibodies. The positivity rates for neutralizing antibodies at a 1:10 titer cutoff were 58.1% at 1 week, 97.8% at 4 weeks, and 78% at 1 year after symptom onset (53.8% in asymptomatic patients and 89.3% in symptomatic patients). The IFA and anti-S1 ELISA IgG results significantly correlated with neutralizing antibody titers. Critical/fatal cases showed significantly higher antibody titers than the asymptomatic or mild-to-moderate illness groups. Nonetheless, the median number of days to the seroconversion of neutralizing antibodies was 10 and 15 in asymptomatic and symptomatic patients, respectively. The asymptomatic group had a significantly higher neutralizing potency index than the mild-to-severe illness groups. Neutralizing antibodies corresponded to earlier seroconversion but had a shorter presence in the asymptomatic group than in the symptomatic group and were still present 1 year after symptom onset in critical/fatal cases.

Evaluation of Humoral Immune Response in Individuals with COVID-19, Coro-naVac and BNT162b2 Vaccines

Giriş: Günümüzde COVID-19 aşı ya da enfeksiyon sonrasında humoral immün yanıtı değerlendirmek amacıyla pek çok immünolojik test yöntemleri kullanılmaktadır. Çalışmamızda da CoronaVac, BNT162b2 ve COVID-19 geçiren kişilerde SARS-CoV-2 humoral immün yanıtı farklı prensipli immünolojik test yöntemleriyle değerlendirmeyi amaçladık. Materyal-metot: COVID-19 tanısı alan 30, CoronaVac aşısı olan 35 ve BNT162b2 aşısı olan 35 kişinin 28 gün sonra alınan serum örnekleri çalışmaya dahil edilmiştir. SARS-CoV 2’nin spike proteini S1 alt biriminin reseptör bağlayıcı bölgesine (RBD) karşı nötralize edici antikorlar üç farklı prensibe yönelik (CMIA, ELISA, LFA) antikor testleri ile (ARCHITECT IgG II Quant test, Abbott, USA/SARS-CoV-2 NeutraLISA, Euroimmun, Lübeck, Almanya/ NeutraXpress™, JOYSBIO Biotechnology Co. Ltd., Tianjin China) çalışıldı. Verilerin istatistiksel değerlendirmesinde IBM SPSS statistic 21 paket programı kullanıldı. Bulgular: Tüm olguların SARS-CoV-II kantitatif antikor titreleri 2635,150 (391,1-8053,425) AU/mL olarak saptandı. Gruplar arasındaki istatistiksel değerlendirmede, COVID-19 geçiren ve BNT162b2aşısı olan kişilerin SARS-CoV-II kantitatif antikor titreleri CoronaVac grubuna kıyasla anlamlı olarak yüksek saptandı (p&amp;lt;0.001). SARS-CoV-II nötralizan antikor inhibisyon yüzdesi tüm olgularda %88,411 (32,904-98,832) iken, COVID-19 geçiren ve BNT162b2 aşısı olan anlamlı olarak yüksek saptandı (p&amp;lt;0.001). Lateral-flow yöntemine göre bağlanan total antikor varlığı 75 (%75) kişide pozitif olarak saptanırken, Nötralizan antikor 60 (%60) kişide pozitif olarak saptandı. Sonuç: Çalışmamıza göre, enfeksiyon ve aşılama sonrası SARS-CoV-2’ ye spesifik humoral immün yanıtın geliştiği görülmektedir. Ayrıca, immunolojik yöntemlerle humoral immün yanıtın değerlendirilmesinde, duyarlılığı ve özgüllüğü yüksek olan testlerin tercih edilmesi gerektiğini düşünmekteyiz.

Determination of Conformational and Functional Stability of Potential Plague Vaccine Candidate in Formulation.

Generally, protein-based vaccines are available in liquid form and are highly susceptible to instability under elevated temperature changes including freezing conditions. There is a need to create a convenient formulation of protein/peptides that can be stored at ambient conditions without loss of activity or production of adverse effects. The efficiency of naturally occurring biocompatible polymer dextran in improving the shelf-life and biological activity of a highly thermally unstable plague vaccine candidate protein called Low Calcium Response V antigen (LcrV), which can be stored at room temperature (30 ± 2 °C), has been evaluated. To determine the preferential interactions with molecular-level insight into solvent-protein interactions, analytical techniques such asspectroscopy, particle size distribution, gel electrophoresis, microscopy, and thermal analysis have been performed along with the evaluation of humoral immune response, invivo. The analytical methods demonstrate the structural stability of the LcrV protein by expressing its interaction with the excipients in the formulation. The invivo studies elicited the biological activity of the formulated antigen with a significantly higher humoral immune response (p-value = 0.047) when compared to the native, adjuvanted antigen. We propose dextran as a potential biopolymer with its co-excipient sodium chloride (NaCl) to provide protein compactness, i.e., prevent protein unfolding by molecular crowding or masking mechanism using preferential hydrophobic interaction for up to three weeks at room temperature (30 ± 2 °C).

Evaluation of Humoral immune responses against coronavirus in healthcare staff in hospitals and medical centers of Shahrekord University of Medical Sciences, Iran

Background and aims: Due to the different levels of exposure of different people to the coronavirus and different levels of immune response among them, this study was designed to investigate the humoral immune responses against the coronavirus disease 2019 (COVID-19) in healthcare staff in hospitals and medical centers admitting COVID-19 patients. Methods: In this descriptive-analytical study, which was performed by call-out, the serum levels of IgM and IgG antibodies in 492 staff of hospitals and medical centers were evaluated using ELISA. Then, factors influencing the immune response of participants were determined. Results: IgG positivity was 11.6% among participants of this study, 19.2% of the staff had a positive polymerase chain reaction (PCR) test, and the IgG positivity rate among them was only 16%. There was no significant relationship between body mass index, underlying diseases, diabetes, immune system-related diseases, herpes simplex virus, workplace, blood type, education level, symptoms, and IgG response (P&gt;0.05). Further, the rate of IgG positivity in healthcare staff indicated a significant relationship only with gender (P=0.005), history of hospitalization (P=0.002) due to COVID-19 and position (P=0.008). Conclusion: This study found that the prevalence of humoral immune response in healthcare staff was lower than the prevalence of the disease based on molecular tests. Based on the results of the present study, it is possible to provide an accurate estimate of the level of involvement and predisposition of healthcare staff in hospital wards and medical centers and to use this information for disease management and control.

P16.39: Immunogenicity of the Inactivated SARS-CoV-2 Vaccine (BBIBP-CorV; Sinopharm) And Short Term Clinical Outcomes in Vaccinated Solid Organ Transplant Recipients: A Prospective Cohort Study

Introduction: Immunocompromised patients have lower seroconversion rate to Coronavirus disease 2019 (COVID-19) vaccination due to immune system dysfunction. So far, the majority of studies in this area are conducted on messenger ribonucleic acid (mRNA) based vaccines. The aim of this study is evaluation of humoral immune response and in transplant patients and short term clinical outcomes in transplant patients vaccinated with SARS-CoV-2 Vaccine (BBIBP-CorV). Methods: All patients older than 18 years old who had been transplanted more than six months prior to recruitment were included in this prospective cohort conducted in Shiraz transplant center as the largest transplant center in Asia from March to December, 2021. The patients received two doses of Sinopopharm 4 weeks apart. The immunogenicity was evaluated through assessment of antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 by enzyme-linked immunosorbent assay (ELISA) method 4 weeks after the first and second dose of vaccine. The patients were followed up weekly up to six months after the second dose monthly up to six months after second dose and were evaluated for occurrence of vaccine adverse events, or getting COVID-19, hospitalization and laboratory parameters. The clinical and laboratoty data of patients was recorded and analyzed by statistical tests. Results: Totally, 921 transplant patients (665 kidney transplantation, 221 liver transplantation, 28 simultaneous pancreas kidney (SPK) and 7 heart transplant recipients). 115 (12.5%) and 239 (26%) patients had acceptable anti S-RBD IgG levels 4 weeks after the first and second dose, respectively. After omitting COVID19 cases with positive PCR test within 6 months before vaccination, 104 (12.6%) and 211 (25.5%) patients had acceptable anti S-RBD level 4 weeks after the first and second dose. Totally, 80 patients (8.68%) got infected with COVID-19 after vaccination.45 (4.9%) patients were admitted in the hospital due to COVID-19 after receiving the second dose of vaccine. None of the patients died during 6 months follow up period. 24 (10.9%) ones developed liver enzyme elevation Also, rise in serum creatinine was observed in 86 (13.5%) kidney transplant patients. Two of SOT recipients experienced biopsy proven rejection which managed by high dose of corticosteroid without any graft loss episodes. Conclusion: The results of our study showed that humoral response rate to Sinopharm vaccine was low in transplant patients. Short time from transplant was only effective factor on low seroconversion rate in transplant patients due to the high dose of immunosuppressive medications in this time frame. It is recommended that the third dose of vaccine, particularly from a different vaccine platform from the inactivated vaccine be administered in transplant patients.

Evaluation of humoral immune responses induced by different SARS-CoV-2 spike trimers from wild-type and emerging variants with individual, sequential, and combinational delivered strategies.

The spike trimer of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is an effective target for inducing neutralizing antibodies by coronavirus disease 2019 (COVID‐19) vaccines. However, the diversity of spike protein from emerging SASR‐CoV‐2 variants has become the major challenge for development of a universal vaccine. To investigate the immunogenicity of spike proteins from various circulating strains including wild type, Delta, and Omicron variants, we produced various natural spike trimers and designed three vaccination strategies, that is, individual, sequential, and bivalent regimens to assess autologous and heterogenous antibody responses in a mouse model. The results indicated that monovalent vaccine strategy with individual spike trimer could only induce binding and neutralizing antibodies against homologous viruses. However, sequential and bivalent immunization with Delta and Omicron spike trimers could induce significantly broader neutralizing antibody responses against heterogenous SARS‐CoV‐2. Interestingly, the spike trimer from Omicron variant showed superior immunogenicity in inducing antibody response against recently emerging XE variant. Taken together, our data supported the development of novel vaccination strategies or multivalent vaccine against emerging variants.

Additive and non-additive genetic effects of humoral immune traits in Japanese quail

In breeding programs, using appropriate models to estimate the variance components with high accuracy is essential. Considering the non-additive genetic effects along with additive effects in evaluation analysis models can be effective in increasing the accuracy of estimates. This study was conducted to fit the best model for estimation of variance components of humoral immune responses (antibody titers against sheep red blood cells [SRBC] and Newcastle disease virus [NDV]), especially non-additive genetic effects (dominance and epistasis) in Japanese quail. The collected records of humoral immune responses were used to estimate genetic parameters using the Bayesian method via Gibbs sampling by fitting 24 different models. The best model for each trait was selected based on Deviance Information Criteria (DIC). Moreover, the residual and additive genetic variance changes were evaluated comparing the models. The results showed that dominance, epistasis, and maternal genetic effects were influenced on humeral immune responses traits except for immunoglobulin Y (IgY). The direct heritability for total antibody titer (AbT), the titer of immunoglobulin Y (IgY), the titer of immunoglobulin M (IgM) against SRBC, antibody titer against NDV (AbNDV), and immune system performance index (IgF) were 0.065, 0.208, 0.117, 0.100, and 0.132, respectively. The contribution of dominance and epistasis as a proportion of phenotypic variance for all traits ranged from 0.070 to 0.221, and 0.087 to 0.251, respectively. A reduction in residual variance were observed in all traits, moreover accuracy of estimated breeding values increased in some traits with adding non-additive genetic effects in the models. Furthermore, the additive genetic variance in the best models decreased for AbT, IgF, and AbNDV traits compared with the simple model (without non-additive genetic effects). The results suggested including the non-additive genetic effects in the genetic models for evaluation of humoral immune responses of quail to obtain precise genetic parameters.

Evaluation of humoral immune responses, effective factors on responses and re-infection in recovered COVID-19 patients

Introduction: Despite large studies on the COVID-19 pandemic, little evidence is available on immune response in recovered patients. Objectives: The aim of this study was to investigate the humoral immune responses (IgM and IgG antibodies) in recovered COVID-19 patients and the role of risk factors and symptoms with respect to the immune responses. Patients and Methods: In this descriptive-analytical study, which was conducted by call-out method, the serum levels of IgM and IgG antibodies were measured using enzyme-linked immunosorbent assay (ELISA) in 248 recovered patients. Effective factors on immune response were determined. Re-infection was investigated through patient follow-up and using information drawn from the hospital information system. Chi-square, t test, ANOVA, and regression analysis in SPSS 15 and Stata 14 were conducted to investigate the relationship between variables. Results: IgG positivity was 86.3% among our participants. Among those who did not show antibody response to COVID-19 (IgM- and IgG-), the most common symptoms at admission were fever, muscle pain (90.9%), chills and anorexia (81.8%). IgG levels remained positive in recovered patients for over seven months. IgG response showed a significant relationship with body mass index, hospital stay length, smoking, residence place, mortality rate, vomiting, and appetite (P&lt;0.05). The re-infection rate after recovery was only 1.6%. Conclusion: High seroprevalence of IgG antibody against COVID-19 and low re-infection rate in Chaharmahal and Bakhtiari province was observed. In addition, the effects of factors such as fever, muscle pain, chills, vomiting, and anorexia on immune responses were demonstrated. These results can be used to manage disease control efficiently, and follow up the treatment process and re-infection in the recovered patients.

Mucosal immunity of mannose-modified chitosan microspheres loaded with the nontyepable Haemophilus influenzae outer membrane protein P6 in BALB/c mice.

Nontypeable Haemophilus influenzae (NTHi) is a common opportunistic pathogen that colonizes the nasopharynx. NTHi infections result in enormous global morbidity in two clinical settings: otitis media in children and acute exacerbation of chronic obstructive pulmonary disease (COPD) in adults. Thus, there is an urgent need to design and develop effective vaccines to prevent morbidity and reduce antibiotic use. The NTHi outer membrane protein P6, a potential vaccine candidate, is highly conserved and effectively induces protective immunity. Here, to enhance mucosal immune responses, P6-loaded mannose-modified chitosan (MC) microspheres (P6-MCMs) were developed for mucosal delivery. MC (18.75%) was synthesized by the reductive amination reaction method using sodium cyanoborohydride (NaBH3CN), and P6-MCMs with an average size of 590.4±16.2 nm were successfully prepared via the tripolyphosphate (TPP) ionotropic gelation process. After intranasal immunization with P6-MCMs, evaluation of humoral immune responses indicated that P6-MCMs enhance both systemic and mucosal immune responses. Evaluation of cellular immune responses indicated that P6-MCMs enhance cellular immunity and trigger a mixed Th1/Th2-type immune response. Importantly, P6-MCMs also trigger a Th17-type immune response. They are effective in promoting lymphocyte proliferation and differentiation without toxicity in vitro. The results also demonstrate that P6-MCMs can effectively induce MHC class I- and II-restricted cross-presentation, promoting CD4+-mediated Th immune responses and CD8+-mediated cytotoxic T lymphocyte (CTL) immune responses. Evaluation of protective immunity indicated that immunization with P6-MCMs can reduce inflammation in the nasal mucosa and the lung and prevent NTHi infection. In conclusion, MCMs are a promising adjuvant-delivery system for vaccines against NTHi.

The Evaluation of Humoral Immune Response to Contagious Bovine Pleuropneumonia in Cattle with Respiratory Disorders by Western Blot Technique, Competitive Enzyme Linked Immunosor-bent Assay and Complement Fixation Test

In this study 253 serum samples from cattle showing respiratory disorders were tested by confirmatory Western Immunoblotting test (IBT), complement fixation test (CFT) and competitive enzyme linked immunosorbent assay (c-ELISA). Two (0.8%) out of 253 serum samples were found to be positive and two were (0.8%) doubtful by CFT while 7 (2.8%) serum samples were found as positive and 25 (9.9%) of them were found to be doubtful by c-ELISA. On the other hand, a core profile of antigenic bands needed to be identified at 110, 98, 95, 62/60 and 48 kDa was not detected in any of the test serum sample. Immunoblot analysis some of serum samples displayed the number of bands between one or three and some of them were highly faint. In order to detect similarities between MmmSc strains related to their electrophoretic profiles, whole cell proteins of Mycoplasma species isolated from cattle and MmmSC reference strains (Mycoplasma mycoides subsp. mycoides SC Botswana (African strain), Mycoplasma mycoides subsp. mycoides SC PG1 (reference strain), Mycoplasma mycoides subsp. mycoides SC V5 (Australian strain), M. bovigenitalium, M. bovirhinis, M. capricolum subsp. capricolum, M.canadense, M.alkalescens and M. bovis) were analysed by sodium dodecyl sulphate polyacrilamide gel elektrophoresis (SDS-PAGE). The result of this analysis indicated that antigens of 220, 78, 82, 68, 24 kDa were common among all tested strains. According to these results, it was thought that positive results by both CFT and c-ELISA, also non specific band patterns observed by IBT might be caused by a cross reaction between tested mycoplasma strains. As conclusion, it is recommended that all the positive results by CFT and c-ELISA be confirmed by IBT.

Evaluation of Humoral Immune Response after SARS-CoV-2 Vaccination Using Two Binding Antibody Assays and a Neutralizing Antibody Assay.

ABSTRACTMultiple vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed and administered to mitigate the coronavirus disease 2019 (COVID-19) pandemic. We assessed the humoral response of BNT162b2 and ChAdOx1 nCoV-19 using Siemens SARS-CoV-2 IgG (sCOVG; cutoff of ≥1.0 U/ml), Abbott SARS-CoV-2 IgG II Quant (CoV-2 IgG II; cutoff of ≥50.0 AU/ml), and GenScript cPASS SARS-CoV-2 neutralization antibody detection kits (cPASS; cutoff of ≥30% inhibition). We collected 710 serum samples (174 samples after BNT162b2 and 536 samples after ChAdOx1 nCoV-19). Venous blood was obtained 3 weeks after first and second vaccinations. In both vaccines, sCOVG, CoV-2 IgG II, and cPASS showed a high seropositive rate (>95.7%) except for cPASS after the first vaccination with ChAdOx1 nCoV-19 (68.8%). Using sCOVG and CoV-2 IgG II, the ratios of antibody value (second/first) increased 10.6- and 11.4-fold in BNT162b2 (first 14.1, second 134.8 U/ml; first 1,416.2, second 14,326.4 AU/ml) and 2.3- and 2.0-fold in ChAdOx1 nCoV-19 (first 4.0, second 9.1 U/ml; first 431.0, second 9,744.0 AU/ml). cPASS-positive results indicated a very high concordance rate with sCOVG and CoV-2 IgG II (>98%), whereas cPASS-negative results showed a relatively low concordance rate (range of 22.2% to 66.7%). To predict cPASS positivity, we suggested additional cutoffs for sCOVG and CoV-2 IgG II at 2.42 U/ml and 284 AU/ml, respectively. In conclusion, BNT162b2 and ChAdOx1 nCoV-19 evoked robust humoral responses. sCOVG and CoV-2 IgG II showed a very strong correlation with cPASS. sCOVG and CoV-2 IgG II may predict the presence of neutralizing antibodies against SARS-CoV-2.IMPORTANCE The Siemens severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG (sCOVG; Siemens Healthcare Diagnostics Inc., NY, USA) and Abbott SARS-CoV-2 IgG II Quant (CoV-2 IgG II; Abbott Laboratories, Sligo, Ireland), which are automated, quantitative SARS-CoV-2-binding antibody assays, have been recently launched. This study aimed to evaluate the humoral immune response of BNT162b2 and ChAdOx1 nCoV-19 vaccines using sCOVG and CoV-2 IgG II and compare the quantitative values with the results of the GenScript surrogate virus neutralization test (cPASS; GenScript, USA Inc., NJ, USA). Our findings demonstrated that both BNT162b2 and ChAdOx1 nCoV-19 elicited a robust humoral response after the first vaccination and further increased after the second vaccination. sCOVG and CoV-2 IgG II showed a strong correlation, and the concordance rates among sCOVG, CoV-2 IgG II, and cPASS were very high in the cPASS-positive results. The additional cutoff sCOVG and CoV-2 IgG II could predict the results of cPASS.

Comparative study between lumpy skin disease virus and sheep pox virus vaccines against recent field isolate of lumpy skin disease virus

Lumpy Skin Disease (LSD) is a vector born disease of cattle, caused by Lumpy Skin Disease Virus (LSDV), there is antigenic relationship between LSDV, Sheeppox virus (SPPV) and Goat pox virus GTPV within a genus Capripoxvirus, accordingly it can be used homologous or heterologous Capripoxvirus strains for vaccination of cattle against LSD. This study compare the efficacy of live attenuated Neethling LSDV vaccine and live attenuated Romanian SSPV Vaccine against recent circulating LSDV field isolate. The evaluation was done in calves as the main host of LSD, through using three different batches for each vaccine type. Experimental calf groups were vaccinated with vaccines batches, and after 21 days serum samples were collected for evaluation of humoral immune response by using SNT and commercial ELISA technique, then the vaccinated calves were challenged by virulent LSDV field isolate. The results of SNT for vaccinated calves by LSDV vaccines indicated mean neutralizing antibody titer 1.2, 1.6 and1.5 log10 for the batches 1, 2 and 3 respectively, while vaccinated calves by SPPV vaccines indicated 1.05, 1.05 and 1.5 log10 for the batches 1,2 and 3 respectively; the ELISA mean sample to positive (S/P) percentage for the vaccine batches 1, 2 and 3 of LSDV were 40, 45 and 42% respectively and for SPPV vaccine batches 1,2 and 3 were 35, 37 and 40 % respectively, the challenge test indicated mean difference titer for the groups of calves vaccinated with LSDV vaccine were 4.2, 4.5 and 3.8 log10 and for groups vaccinated with SPPV vaccine were 2.6, 2 and 2.65 log10 respectively, it was concluded that potential using of Neethling LSDV vaccine against LSD is superior for combating and prevention of the lumpy skin disease.

New potent epitopes from Leptospira borgpetersenii for the stimulation of humoral and cell-mediated immune responses: Experimental and theoretical studies

The rhKU_Sej_LRR_2271 protein is introduced as one of the leptospiral vaccine candidates since it contains the predicted immunogenic epitopes. The in-silico sequence and structural based analysis have been used in this study to analyze MHC class I and class II-restricted epitopes of the protein. Six epitope prediction programs were employed, which the epitopes with high prediction scores from each program were aligned. The 21 of potentially unrestrained epitopes with prediction scores above the cut-off value from at least two prediction programs were selected. The 3D-molecular modeling, docking, and molecular dynamic simulation were performed to evaluate the affinity binding between peptide-MHC complex and T-cell receptor. One promising epitope, which is 171-LLFLPLIKI, showed the potency in binding to both MHC class I and II alleles. Two newly designed peptides containing epitopes which can bind to over 3 of MHC alleles, LL17:171-LLFLPLIKILYVDRNKL-187 and SL19:209-SLNSGIKALPFNYEKLVNL-227, significantly increased interferon-gamma (IFNg)-producing specific T-cell responses in the rhKU_Sej_LRR_2271 immunized rabbits compared to nonimmunized rabbits. The LL17 peptide can also induce interferon-gamma-producing specific CD4 + T-cell responses in the immunized rabbits. For the evaluation of humoral immune responses, the immunized rabbits have a significantly greater amount of specific IgG in plasma than the nonimmunized rabbits. Ex-vivo study of T-cell responses in animal model using flow cytometry confirmed an accomplishment of the theoretically in-silico analysis for discovering potential T-cell epitopes of the protein. The results show that the rhKU_Sej_LRR_2271 protein containing promiscuous T-cell epitopes, which can induce both humoral and cell-mediated immune responses, is a prospective protein candidate for leptospiral vaccine development. • 21 potent T-cell epitopes form rhKU_Sej_LRR_2271 were predicted by six programs. • Evaluate pMHC/TCR complex stability by MD simulation. • LL17-LLFLPLIKILYVDRNK significantly induce IFNg-producing specific CD4 + T cell. • rhKU_Sej_LRR_2271 induces humoral and cell-mediated immunity in immunized rabbit. • rhKU_Sej_LRR_2271 protein contains promiscuous epitopes which can be vaccine candidate.