IgG Antibody Titers Research Articles

Impact of methotrexate on humoral and cellular immune responses to SARS-CoV-2 mRNA vaccine in patients with rheumatoid arthritis.

The aim of this study wasto longitudinally evaluate the undetermined impact of methotrexate (MTX) on the cumulative immunogenicity elicited by three doses of SARS-CoV-2 mRNA vaccination in patients with rheumatoid arthritis (RA). We prospectively evaluated vaccine-induced immune responses following the first dose, 1 and 6months after the second dose, and 1month after the third dose of BNT162b2 or mRNA-1273 in 144 SARS-CoV-2 naïve participants (70 patients with RA, 29 disease controls without immunosuppressive conditions, and 45 healthy controls). Humoral immune responses were assessed by quantifying anti-spike IgG antibody titers and the capacity of circulating antibodies to neutralize the ancestral SARS-CoV-2 strain and the Alpha, Delta, and Omicron variants. Vaccine-induced T-cell responses were measured using an interferon-gamma release assay. At 1 and 6months after the second dose, anti-spike titers were highest in healthy controls, followed by disease controls and patients with RA. Multivariate analyses revealed that MTX treatment was significantly associated with a decrease in anti-spike titers, neutralizing activity, and SARS-CoV-2-specific interferon-gamma levels. Furthermore, MTX dose per body weight was negatively correlated with these two indices of humoral immune response. The third vaccine dose boosted anti-spike titers, especially in patients receiving MTX, while sera from these patients neutralized the Omicron variant far less robustly than those from healthy controls. In conclusion,MTX attenuated immunogenicity following two doses of SARS-CoV-2 mRNA vaccine in patients with RA, particularly resulting in dose-dependent suppression of the humoral immune response. Furthermore, MTX deteriorated the neutralizing activity against the Omicron variant, even after the third immunization.

Measurements and Accuracy of IgM and IgG Anti Phenolic Glycolipid-1 Levels in Blood Serum for Early Detection Mycobacterium leprae by using Enzyme-Linked Immunosorbent Assay (ELISA): A Reality of a Laboratory

Indonesia was the third most recent case of leprosy globally in 2020 with 11,173 people, after India and Brazil. Most of the leprosy manifestations are asymptomatic. This is possibly as subclinical leprosy which individuals without leprosy symptoms but have leprosy specific antibodies high levels, so it has the potential to become a transmission and disability. Therefore, an ELISA test need for early detection in preventing leprosy transmission. This study aims to measure IgM and IgG antibody levels in leprosy patients and assess the accuracy of the measurement results. This research is a cross-sectional study. Five patients' blood samples have analyzed for IgM and IgG anti-PGL-1 antibody levels by ELISA. Accuracy interpretation of this measurement based on the %CV. Antibody levels were classified based on the cut-off <605 u/ml as IgM seronegative or <630 u/ml as IgG seronegative, 605–1000 u/ml as low seropositive IgM or 630-1000 u/ml as low seropositive IgG, and >1000 u/ml as high seropositive IgM and IgG. Among five patients examined, 40% had high seropositive leprosy with anti-PGL-1 IgM and IgG antibody titers>1000 u/ml, and 60% of patients had seronegative leprosy. Accuracy in this ELISA test shows high accuracy with %CV <10% in the conversion of OD to antibody titer levels. IgM and IgG Anti PGL-1 antibody titers by ELISA as one of the parameters in identifying patients at higher risk of leprosy. A significant portion of patients with high seropositive leprosy with high accuracy.

Elicitation of T-cell-derived IFN-γ-dependent immunity by highly conserved Plasmodium ovale curtisi Duffy binding protein domain region II (PocDBP-RII)

BackgroundInfections with Plasmodium ovale are widely distributed but rarely investigated, and the resulting burden of disease has been underestimated. Plasmodium ovale curtisi Duffy binding protein domain region II (PocDBP-RII) is an essential ligand for reticulocyte recognition and host cell invasion by P. ovale curtisi. However, the genomic variation, antigenicity and immunogenicity of PocDBP-RII remain major knowledge gaps.MethodsA total of 93 P. ovale curtisi samples were collected from migrant workers who returned to China from 17 countries in Africa between 2012 and 2016. The genetic polymorphism, natural selection and copy number variation (CNV) were investigated by sequencing and real-time PCR. The antigenicity and immunogenicity of the recombinant PocDBP-RII (rPocDBP-RII) protein were further examined, and the humoral and cellular responses of immunized mice were assessed using protein microarrays and flow cytometry.ResultsEfficiently expressed and purified rPocDBP-RII (39 kDa) was successfully used as an antigen for immunization in mice. The haplotype diversity (Hd) of PocDBP-RII gene was 0.105, and the nucleotide diversity index (π) was 0.00011. No increased copy number was found among the collected isolates of P. ovale curtisi. Furthermore, rPocDBP-RII induced persistent antigen-specific antibody production with a serum IgG antibody titer of 1: 16,000. IFN-γ-producing T cells, rather than IL-10-producing cells, were activated in response to the stimulation of rPocDBP-RII. Compared to PBS-immunized mice (negative control), there was a higher percentage of CD4+CD44highCD62L− T cells (effector memory T cells) and CD8+CD44highCD62L+ T cells (central memory T cells) in rPocDBP-RII‑immunized mice.ConclusionsPocDBP-RII sequences were highly conserved in clinical isolates of P. ovale curtisi. rPocDBP-RII protein could mediate protective blood-stage immunity through IFN-γ-producing CD4+ and CD8+ T cells and memory T cells, in addition to inducing specific antibodies. Our results suggested that rPocDBP-RII protein has potential as a vaccine candidate to provide assessment and guidance for malaria control and elimination activities.Graphical

TLR-2 agonist Pam3CSK4 has no therapeutic effect on visceral leishmaniasis in BALB/c mice and may enhance the pathogenesis of the disease

Most of the existing Leishmania-related research about TLR-2 agonists was focusing on their role as adjuvants in the vaccine, few studied its therapeutic effect. This paper aims to explore the therapeutic effect of TLR-2 agonist Pam3CSK4 on Leishmania-infected mice and the underlying immune molecular mechanisms. In L. donovani-infected BALB/c mice, one group was treated with Pam3CSK4 after infection and the other group was not treated. Normal uninfected mice treated with Pam3CSK4 or untreated were used as controls. Parasite load, hepatic pathology and serum antibodies were detected to assess the severity of the infection. The expression of immune-related genes, spleen lymphocyte subsets and liver RNA-seq were employed to reveal possible molecular mechanisms. The results showed that the liver and spleen parasite load of infected mice in Pam3CSK4 treated and untreated groups had no statistical difference, indicating Pam3CSK4 might have no therapeutic effect on visceral leishmaniasis. Infected mice treated with Pam3CSK4 possessed more hepatic inflammation focus, lower IgG and IgG2a antibody titers, and a lower proportion of spleen CD3+CD4+ T cells. Transcriptome analysis revealed that Th1/Th2 differentiation, NK cells, Th17 cell, complement system and calcium signaling pathways were down-regulated post-treatment of Pam3CSK4. In this study, TLR-2 agonist Pam3CSK4 showed no therapeutic effect on visceral leishmaniasis in BALB/c mice and might enhance the pathogenesis of the disease possibly due to the down-regulation of several immune-related pathways, which can improve our understanding of the role of TLR-2 in both treatment and vaccine development.

The Immunogenic Potential of PCSK9 Peptide Vaccine in Mice.

To evaluate the immunogenic potential of the carrier-free peptide-based anti-PCSK9 (proprotein convertase subtilisin/kexin 9) vaccine in albino mice. The immunogenic pcsk9 peptide and 0.4% alum adjuvant were mixed thoroughly at a 1:1 ratio and used as a vaccine formulation. To assess the humoral immune response, animals' blood was sampled two weeks after the last immunization. The ELISA method was employed to measure serum anti-PCSK9 antibody titers, PCSK9 concentrations, and PCSK9/LDLR interaction. ELISA analysis showed significant induction of IgG antibody titers by PCSK9 peptide vaccine in vaccinated mice sera compared to the control mice (in male and female mice were 12000±586 and 11566±642, respectively, p<0.001). Mechanistic analyses showed a significant reduction in serum PCSK9 concentrations by vaccine-induced antibodies in vaccine groups compared to the control groups (in male mice by 29±5 ng/mL (22.4%), p<0.001 and female mice by 26±5 ng / mL (21.0%), p<0.001). Serum concentrations of PCSK9 in control and vaccine groups were 131±8.6 ng / mL and 102±8.1 ng/ml in male mice and 124±6 ng/ml and 98±10 ng/ml in female mice, respectively. Moreover, vaccine-induced antibodies inhibited the PCSK9-LDLR interaction in male and female groups by 34% and 26%, respectively. No significant difference was detected between the male and female groups in all tests (p>0.05). According to our results, the PCSK9 peptide vaccine provoked the humoral immune system in albino mice to produce functional antibodies that inhibit plasma PCSK9. These effects were seen in both genders without any significant difference.

Real-world assessment of immunogenicity in immunocompromised individuals following SARS-CoV-2 mRNA vaccination: a one-year follow-up of the prospective clinical trial COVAXID.

Immunocompromised patients have varying responses to SARS-CoV-2 mRNA vaccination. However, there is limited information available from prospective clinical trial cohorts with respect to long-term immunogenicity-related responses in these patient groups following three or four vaccine doses, and in applicable cases infection. In a real-world setting, we assessed the long-term immunogenicity-related responses in patients with primary and secondary immunodeficiencies from the prospective open-label clinical trial COVAXID. The original clinical trial protocol included two vaccine doses given on days 0 and 21, with antibody titres measured at six different timepoints over six months. The study cohort has subsequently been followed for one year with antibody responses evaluated in relation to the third and fourth vaccine dose, and in applicable cases SARS-CoV-2 infection. In total 356/539 patients were included in the extended cohort. Blood samples were analysed for binding antibody titres and neutralisation against the Spike protein for all SARS-CoV-2 variants prevailing during the study period, including Omicron subvariants. SARS-CoV-2 infections that did not require hospital care were recorded through quarterly in-person, or phone-, interviews and assessment of IgG antibody titres against SARS-CoV-2 Nucleocapsid. The original clinical trial was registered in EudraCT (2021-000175-37) and clinicaltrials.gov (NCT04780659). The third vaccine dose significantly increased Spike IgG titres against all the SARS-CoV-2 variants analysed in all immunocompromised patient groups. Similarly, neutralisation also increased against all variants studied, except for Omicron. Omicron-specific neutralisation, however, increased after a fourth dose as well as after three doses and infection in many of the patient subgroups. Noteworthy, however, while many patient groups mounted strong serological responses after three and four vaccine doses, comparably weak responders were found among patient subgroups with specific primary immunodeficiencies and subgroups with immunosuppressive medication. The study identifies particularly affected patient groups in terms of development of long-term immunity among a larger group of immunocompromised patients. In particular, the results highlight poor vaccine-elicited neutralising responses towards Omicron subvariants in specific subgroups. The results provide additional knowledge of relevance for future vaccination strategies. The present studies were supported by grants from the Swedish Research Council, the Knut and Alice Wallenberg Foundation, Nordstjernan AB, Region Stockholm, and Karolinska Institutet.

Robust antibody response after the third mRNA coronavirus vaccination in Japanese hemodialysis patients

BackgroundHemodialysis patients have chronic kidney disease, are often elderly, and have many complications such as hypertension, type 2 diabetes, cardiac disease, and cerebrovascular disease. Therefore, hemodialysis patients infected with COVID-19 are prone to severe disease. Vaccination is the most promising means of preventing the onset and reducing the severity of COVID-19. However, many reports have found that anti-spike antibody titers after two doses of mRNA vaccine are lower in hemodialysis patients than in healthy controls. For this reason, a third vaccination is recommended for hemodialysis patients. In Japan, there are several reports of a third vaccination, especially for hemodialysis patients. In this study, we also examined the antibody response to COVID-19 vaccine in Japanese hemodialysis patients who received the third dose of the vaccine.MethodsStudy participants received a third vaccination (257 with BNT162b2 vaccine and 5 with mRNA-1273 vaccine) approximately 7–9 months after the second (BNT162b2 vaccine). Anti-SARS-CoV-2 spike IgG antibody titers were measured (Abbott SARS-CoV-2 IgG II Quan) in 185 hemodialysis patients and 109 healthcare workers approximately 2 weeks after the second vaccination and in 162 hemodialysis patients and 100 healthcare workers approximately 2 weeks after the third.ResultsFollowing the second vaccination, 97.6% of the hemodialysis group and 100% of the control group were positive for the anti-spike antibody. The median level of the anti-spike antibody was 2728.7 AU/mL (IQR, 1024.2–7688.2 AU/mL) in the hemodialysis group and 10,500 AU/ml (IQR, 9346.1–2,4500 AU/mL) in the controls. Following the third vaccination, 99.4% of the hemodialysis group (only one person tested negative for the antibody) and 100% of the control group were positive for the anti-spike antibody. The median level of the anti-spike antibody was 20,000 AU/mL (IQR, 7729–37,000 AU/mL) in the hemodialysis group and 21,500 AU/ml (IQR, 14,000–32,250 AU/mL) in the control group. The factors involved in the low response to the BNT152b2 vaccine after the second vaccination included old age, low BMI, low Cr index, low nPCR, low GNRI, low lymphocyte count, steroid administration, and complications related to blood disorders. However, in hemodialysis patients, the response after the third vaccination was excellent, and all factors associated with the suppressed response to these vaccines were no longer significant.ConclusionsThe humoral response of hemodialysis patients to two doses of mRNA vaccine was weaker than that of healthy controls. However, a third vaccination eliminated that difference.

Multi-phasic gene profiling using candidate gene approach predict the capacity of specific antibody production and maintenance following COVID-19 vaccination in Japanese population.

Vaccination against severe acute respiratory syndrome coronavirus type 2 is highly effective in preventing infection and reducing the severity of coronavirus disease (COVID-19). However, acquired humoral immunity wanes within six months. Focusing on the different tempo of acquisition and attenuation of specific antibody titers in individuals, we investigated the impact of genetic polymorphisms on antibody production after COVID-19 vaccination. In total 236 healthcare workers from a Japanese municipal hospital, who received two doses of the vaccine were recruited. We employed a candidate gene approach to identify the target genetic polymorphisms affecting antibody production after vaccination. DNA samples from the study populations were genotyped for 33 polymorphisms in 15 distinct candidate genes encoding proteins involved in antigen-presenting cell activation, T cell activation, T-B interaction, and B cell survival. We measured total anti-SARS-Cov2 spike IgG antibody titers and analyzed the association with genetic polymorphisms at several time points after vaccination using an unbiased statistical method, and stepwise logistic regression following multivariate regression. Significant associations were observed between seven SNPs in NLRP3, OAS1, IL12B, CTLA4, and IL4, and antibody titers at 3 weeks after the first vaccination as an initial response. Six SNPs in NLRP3, TNF, OAS1, IL12B, and CTLA4 were associated with high responders with serum antibody titer > 4000 BAU/ml as boosting effect at 3 weeks after the second vaccination. Analysis of long-term maintenance showed the significance of the three SNPs in IL12B, IL7R, and MIF for the maintenance of antibody titers and that in BAFF for attenuation of neutralizing antibodies. Finally, we proposed a predictive model composed of gene profiles to identify the individuals with rapid antibody attenuation by receiver operating characteristic (ROC) analysis (area under the curve (AUC)= 0.76, sensitivity = 82.5%, specificity=67.8%). The candidate gene approach successfully showed shifting responsible gene profiles and initial and boosting effect mainly related to the priming phase into antibody maintenance including B cell survival, which traces the phase of immune reactions. These gene profiles provide valuable information for further investigation of humoral immunity against COVID-19 and for building a strategy for personalized vaccine schedules.

Lactobacillus plantarum surface-displayed Eimeria tenella profilin antigens with FliC flagellin elicit protection against coccidiosis in chickens

Coccidiosis is a parasitic disease in the intestine caused by the genus Eimeria that poses a substantial economic threat to the broiler breeding industry. The misuse of chemoprophylaxis and live oocyst vaccines has a negative impact on chicken reproductivity. Therefore, there is a pressing need to develop safe, convenient, and effective vaccines. Lactic acid bacteria can be used as a means to deliver mucosal vaccines against intestinal pathogens, which is a promising strategy. In this study, a recombinant Lactobacillus plantarum (L. plantarum) with surface-expressed antigens constructed from the fusion of Eimeria tenella (E. tenella) antigen profilin and the Salmonella enterica serovar Typhimurium flagellin protein FliC was created. After oral immunization with the recombinant L. plantarum, T-cell differentiation was analyzed by flow cytometry, and specific antibody levels were determined via indirect ELISA. Oocyst shedding, body weight, and cecum lesions were assessed as measures of protective immunity after challenge with E. tenella. The results of this study demonstrate the effectiveness of recombinant L. plantarum as an immunization agent for chickens. Specific IgA titers in the intestine and specific IgG antibody titers in the serum were significantly higher in chickens immunized with recombinant L. plantarum (P < 0.001). Additionally, the levels of IL-2 (P < 0.05) and IFN-γ (P < 0.01) in the serum were markedly increased. Recombinant L. plantarum induced T-cell differentiation, resulting in a higher proportion of CD4+ and CD8+ T cells in splenocytes (P < 0.001). Fecal oocyst shedding in the immunized group was significantly reduced (P < 0.001). Additionally, recombinant L. plantarum significantly relieved pathological damage in the cecum, as evidenced by lesion scores (P < 0.01) and histopathological cecum sections. In conclusion, the present study provides evidence to support the possibility of using L. plantarum as a promising carrier for the delivery of protective antigens to effectively protect chickens against coccidiosis.

Immunization with lytic polysaccharide monooxygenase CbpD induces protective immunity against Pseudomonas aeruginosa pneumonia

Pseudomonas aeruginosa (PA) CbpD belongs to the lytic polysaccharide monooxygenases (LPMOs), a family of enzymes that cleave chitin or related polysaccharides. Here, we demonstrate a virulence role of CbpD in PA pneumonia linked to impairment of host complement function and opsonophagocytic clearance. Following intratracheal challenge, a PA ΔCbpD mutant was more easily cleared and produced less mortality than the wild-type parent strain. The x-ray crystal structure of the CbpD LPMO domain was solved to subatomic resolution (0.75Å) and its two additional domains modeled by small-angle X-ray scattering and Alphafold2 machine-learning algorithms, allowing structure-based immune epitope mapping. Immunization of naive mice with recombinant CbpD generated high IgG antibody titers that promoted human neutrophil opsonophagocytic killing, neutralized enzymatic activity, and protected against lethal PA pneumonia and sepsis. IgG antibodies generated against full-length CbpD or its noncatalytic M2+CBM73 domains were opsonic and protective, even in previously PA-exposed mice, while antibodies targeting the AA10 domain were not. Preexisting antibodies in PA-colonized cystic fibrosis patients primarily target the CbpD AA10 catalytic domain. Further exploration of LPMO family proteins, present across many clinically important and antibiotic-resistant human pathogens, may yield novel and effective vaccine antigens.

Nasopharyngeal Carcinoma (NPC) in Russia and Epstein - Barr Virus Types: Analysis of the Influence of Gender, Ethnic and Age Factors on the Virus Types Spread in NPC Patients

Introduction: The discovery of two molecular types of Epstein-Barr virus, EBV-1 and EBV-2, with different biological properties, stimulated the search for new neoplasms associated with each type of the virus. Objective: The aim of this study was to analyze the prevalence of EBV-1 and EBV-2 in NPC patients from different climatic and geographical regions of Russia, representatives of different gender, ethnic and age groups of patients. Materials and Methods: Using nested PCR EBV types were determined in blood plasma of NPC and other non-EBV-associated tumors of the oral cavity (OTOC/EBV-) patients from the North Caucasus (NCFD) and the Central (CFD) Federal Districts of Russia. IgG and IgA antibody titers to viral capsid antigen (VCA) were determined by indirect immunofluorescence. Results: The studies carried out have shown that NPC and OTOC/EBV- patients were infected with both EBV types in roughly the same ratio. There were also no statistically significant differences in serological activities of NPC patients infected with EBV-1 or EBV-2. The prevalence of EBV-2 types 1 and 2 was not influenced by gender or ethno-geographic affiliation of NPC patients. The only difference was EBV-2 predominance in NPC patients under 60, and EBV-1 predominance in those over 60 years old. Conclusion: The absence of a predominance of one of the EBV types in NPC patients indicates that neither EBV-1 nor EBV-2 is strictly NPC-associated in Russia, and that different ethnic and climatic-geographical factors in the spread of virus types in NPC patients are not playing an essential role.

Development of hybrid immunity during a period of high incidence of Omicron infections.

Seroprevalence and the proportion of people with neutralizing activity (functional immunity) against SARS-CoV-2 variants were high in early 2022. In this prospective, population- based, multi-region cohort study, we assessed the development of functional and hybrid immunity (induced by vaccination and infection) in the general population during this period of high incidence of infections with Omicron variants. We randomly selected and assessed individuals aged ≥16 years from the general population in southern (n = 739) and north-eastern (n = 964) Switzerland in March 2022. We assessed them again in June/July 2022, supplemented with a random sample from western (n = 850) Switzerland. We measured SARS-CoV-2 specific IgG antibodies and SARS-CoV-2 neutralizing antibodies against three variants (ancestral strain, Delta, Omicron). Seroprevalence remained stable from March 2022 (97.6%, n = 1894) to June/July 2022 (98.4%, n = 2553). In June/July, the percentage of individuals with neutralizing capacity against ancestral strain was 94.2%, against Delta 90.8% and against Omicron 84.9%, and 50.6% developed hybrid immunity. Individuals with hybrid immunity had highest median levels of anti-spike IgG antibodies titres [4518 World Health Organization units per millilitre (WHO U/mL)] compared with those with only vaccine- (4304 WHO U/mL) or infection- (269 WHO U/mL) induced immunity, and highest neutralization capacity against ancestral strain (hybrid: 99.8%, vaccinated: 98%, infected: 47.5%), Delta (hybrid: 99%, vaccinated: 92.2%, infected: 38.7%) and Omicron (hybrid: 96.4%, vaccinated: 79.5%, infected: 47.5%). This first study on functional and hybrid immunity in the Swiss general population after Omicron waves showed that SARS-CoV-2 has become endemic. The high levels of antibodies and neutralization support the emerging recommendations of some countries where booster vaccinations are still strongly recommended for vulnerable persons but less so for the general population.

Utility of Borrelia-specific IgM and IgG antibody titer determinations during a 12-year period - results from a clinical laboratory in Northern Sweden.

Interpretation of serological findings in suspected Lyme borreliosis (LB) is challenging and IgM reactivities may have low predictive value. Therefore, if used indiscriminately, there is a risk for incorrect diagnosis of LB. To evaluate the usefulness of IgM titer determination, we performed a study of the prevalence of Borrelia-specific antibodies in serological samples from patients with suspected LB analyzed during the period 2010 - 2021 at the University Hospital of Umeå in Sweden. In total, 19,335 samples had been analyzed for the presence of IgG and IgM antibodies. Overall, there were higher percentages of IgM positive or borderline titers, 1,847 (9.6%) and 905 (4.7%), respectively, than IgG positive or borderline titers, 959 (5.0%) and 406 (2.1%), respectively. Peak number of samples were recorded 2012 - 2013, exceeding 1,800, whereas there were around 1,200 during 2020 - 2021. The peak number of positive IgG and/or positive IgM samples were observed during the period 2015 - 2017 with close to, or above 400, and concomitantly, the proportion of IgG positive samples increased markedly. For IgG positive samples, the increase followed a positive linear time trend (P< 0.001). Peak monthly numbers were observed during August, September, and October. This seasonal increase was significant for the IgG positive group (P< 0.05), but not for the IgM positive/IgG negative group. Repeated samples were obtained from 3,188 individuals and of the initial samples 2,817 were (88%) IgG negative and 2,315 (72%) were IgM negative and of these, 130 (4%) showed IgG seroconversion and 300 (9%) IgM seroconversion. Collectively, the data demonstrate that IgG and/or IgM positive samples represented a minority of all samples, even when repeated sampling had occurred, and IgM positive samples were much more common than IgG positive samples. Thus, the accuracy of the clinical suspicion was low and this will lead to a low predictive value of the analysis, in particular of IgM. These findings question the use of IgM titer determination as a routine analysis.

PLGA nanoparticles containing Intimin-Flagellin fusion protein for E. coli O157:H7 nano-vaccine

Escherichia coli O157:H7 is a foodborne pathogen that can lead to severe gastrointestinal diseases in humans. Vaccination is a promising strategy for preventing E. coli O157:H7 infections, which offers socio-economic benefits and provides the possibility of stimulating both humoral and cellular immune responses at systemic and mucosal sites. In this study, we developed a needle-free vaccine candidate against E. coli O157:H7 using poly(lactic-co-glycolic acid) (PLGA) nanoparticles entrapping a chimeric Intimin-Flagellin (IF) protein. The IF protein was expressed and verified using SDS-PAGE and western blot analysis, with a yield of 1/7 mg/L and a molecular weight of approximately 70 kDa. The prepared nanoparticles showed uniformly shaped spherical particles in the 200-nm range, as confirmed by SEM and DLS analysis. Three different routes of vaccine administration were used, including intranasal, oral, and subcutaneous, and the groups vaccinated with NPs protein had a higher antibody response compared to those receiving free protein. Subcutaneous administration of IF-NPs resulted in the highest level of IgG antibody titer, while oral administration of IF-NPs produced the highest amount of IgA antibody titer. Finally, all mice in the nanoparticle- intranasal and oral administered groups challenged with 100LD50 survived, while all control mice died before day 5. Based on these findings, we conclude that the PLGA-encapsulated IF protein has the potential to serve as a promising needle-free vaccine candidate against E. coli O157:H7.

Estimation levels of (IL-4, IL-12, and IL-17) and other immunological characteristics in Herpes zoster patients in the southern Iraqi \province of Thi-Qar

Varicella-zoster virus (VZV), which was dormant in the dorsal root ganglia or cranial nerve, reactivates to produce the viral illness shingle. Immunosenescence, which includes the documented decline of cell-mediated immunity with aging, can result in in the VZV reactivation. While HZ is typically mild in young, persons who are in good health, while older individuals are more likely to experience complications. The present study was carried out during the months of July 2022 to January 2023 in the governorate of Thi-Qar We examined the levels of VZV IgG antibodies, IL-4, IL-12,IL-17 and checking level VTN in the blood of 70 HZ patients who did not suffer from superinfection. 30 individuals of a comparable age who were healthy and free of infectious and inflammatory diseases made up the control group. blood samples were collected from them and examined via the ELISA system. While the plasma vitronectin level dropped in HZ patients when in comparison to the control group, both the serum levels of the cytokines IL-4, IL-12, and IL-17 as well as the VZV IgG antibody titer considerably rose. According to the results, HZ patients without chronic illnesses had significantly greater levels of IL-17. compared to individuals suffering from chronic illnesses. Additionally, IL-12 levels were noticeably higher in females than in males. Age and sex differences were not found to be significantly different in the research.

Comparative Assessment of the Kinetics of Cellular and Humoral Immune Responses to COVID-19 Vaccination in Cancer Patients.

The kinetics of immune responses to various SARS-CoV-2 vaccines in cancer patients were investigated. In total, 57 cancer patients who received BNT162b2-RNA or BBIBP-CorV vaccines were enrolled. Cellular and humoral immunity were assessed at three-time points, before the first vaccine dose and 14-21 days after the first and second doses. Chemiluminescent microparticle immunoassay was used to evaluate SARS-CoV-2 anti-spike IgG response, and QuantiFERON® SARS-CoV-2 kit assessed T-cell response. Data showed that cancer patients' CD4+ and CD8+ T cell-median IFN-γ secretion of SARS-CoV-2 antigens increased after the first and second vaccine doses (p = 0.027 and p = 0.042). BNT162b2 vaccinees had significantly higher IFN-γ levels to CD4+ and CD8+ T cell epitopes than BBIBP-CorV vaccinees (p = 0.028). There was a positive correlation between IgG antibody titer and T cell response regardless of vaccine type (p < 0.05). This study is one of the first to investigate cellular and humoral immune responses to SARS-CoV-2 immunization in cancer patients on active therapy after each vaccine dose. COVID-19 immunizations helped cancer patients develop an effective immune response. Understanding the cellular and humoral immune response to COVID-19 in cancer patients undergoing active treatment is necessary to improve vaccines and avoid future SARS pandemics.

A bioengineered pseudovirus nanoparticle displaying SARS-CoV 2 RBD fully protects mice from mortality and weight loss caused by SARS-CoV 2 challenge.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused considerable morbidity and mortality worldwide. Although authorized COVID-19 vaccines have been shown highly effective, their significantly lower efficacy against heterologous variants, and the rapid decrease of vaccine-elicited immunity raises serious concerns, calling for improved vaccine tactics. To this end, a pseudovirus nanoparticle (PVNP) displaying the receptor binding domains (RBDs) of SARS-CoV-2 spike, named S-RBD, was generated and shown it as a promising COVID-19 vaccine candidate. The S-RBD PVNP was produced using both prokaryotic and eukaryotic systems. A 3D structural model of the S-RBD PVNPs was built based on the known structures of the S60 particle and RBDs, revealing an S60 particle-based icosahedral symmetry with multiple surface-displayed RBDs that retain authentic conformations and receptor-binding functions. The PVNP is highly immunogenic, eliciting high titers of RBD-specific IgG and neutralizing antibodies in mice. The S-RBD PVNP demonstrated exceptional protective efficacy, and fully (100%) protected K18-hACE2 mice from mortality and weight loss after a lethal SARS-CoV-2 challenge, supporting the S-RBD PVNPs as a potent COVID-19 vaccine candidate. By contrast, a PVNP displaying the N-terminal domain (NTD) of SARS-CoV-2 spike exhibited only 50% protective efficacy. Since the RBD antigens of our PVNP vaccine are adjustable as needed to address the emergence of future variants, and various S-RBD PVNPs can be combined as a cocktail vaccine for broad efficacy, these non-replicating PVNPs offer a flexible platform for a safe, effective COVID-19 vaccine with minimal manufacturing cost and time.

Bacterial shedding and serologic responses following an outbreak of Salmonella Typhi in an endemic cohort

BackgroundSalmonella enterica serovar Typhi (Salmonella Typhi) is the cause of typhoid fever. Salmonella Typhi may be transmitted through shedding in the stool, which can continue after recovery from acute illness. Shedding is detected by culturing stool, which is challenging to co-ordinate at scale. We hypothesised that sero-surveillance would direct us to those shedding Salmonella Typhi in stool following a typhoid outbreak.MethodsIn 2016 a typhoid outbreak affected one in four residents of a Nursing School in Malosa, Malawi. The Department of Health asked for assistance to identify nursing students that might spread the outbreak to other health facilities. We measured IgG antibody titres against Vi capsular polysaccharide (anti-Vi IgG) and IgM / IgG antibodies against H:d flagellin (anti-H:d) three and six months after the outbreak. We selected participants in the highest and lowest deciles for anti-Vi IgG titre (measured at visit one) and obtained stool for Salmonella culture and PCR. All participants reported whether they had experienced fever persisting for three days or more during the outbreak (in keeping with the WHO definitions of ‘suspected typhoid’). We tested for salmonellae in the Nursing School environment. ResultsWe obtained 320 paired serum samples from 407 residents. We cultured stool from 25 residents with high anti-Vi IgG titres and 24 residents with low titres. We did not recover Salmonella Typhi from stool; four stool samples yielded non-typhoidal salmonellae; one sample produced a positive PCR amplification for a Salmonella Typhi target. Median anti-Vi and anti-H:d IgG titres fell among participants who reported persistent fever. There was a smaller fall in anti-H:d IgG titres among participants who did not report persistent fever. Non-typhoidal salmonellae were identified in water sampled at source and from a kitchen tap.ConclusionHigh titres of anti-Vi IgG did not identify culture-confirmed shedding of Salmonella Typhi. There was a clear serologic signal of recent typhoid exposure in the cohort, represented by waning IgG antibody titres over time. The presence of non-typhoidal salmonellae in drinking water indicates sub-optimal sanitation. Developing methods to detect and treat shedding remains an important priority to complement typhoid conjugate vaccination in efforts to achieve typhoid elimination.

Lipidated brartemicin adjuvant p-C18Brar is a promising α,α′-trehalose 6,6′-dilipid for use in ovine pneumonia vaccines

Abstract Ovine pneumonia is a disease in sheep that is associated with major animal welfare issues and economic losses and for which there is no effective vaccine. We tested the adjuvanticity of our most promising α,α′-trehalose 6,6′-glycolipids, lipidated brartemicin adjuvants p-C18Brar (3), o-C18Brar (4), and amide-TDB (5) in vaccines for ovine pneumonia containing Mannheimia haemolytica and Mycoplasma ovipneumoniae whole cell antigens. p-C18Brar (3) and o-C18Brar (4) led to strong antigen-specific IgG antibody titres that were better than those elicited by the prototypical α,α′-trehalose glycolipid trehalose dibehenate (TDB, 2) and amide-TDB (5). T-cell responses, as determined by measuring IFN-γ and IL-17A production from antigen-stimulated whole blood cultures, revealed that p-C18Brar (3), but not TDB (2), o-C18Brar (4), or amide-TDB (5), led to statistically significant increases in these cytokines. We then optimised the synthesis of p-C18Brar (3) (3 steps, 72 % overall yield) and undertook further vaccination studies to determine the optimal dose of p-C18Brar (3) that would be used for future large scale ovine pneumonia field trials. At a dose of 3.75 mg per vaccine, the adjuvanticity of p-C18Brar (3), as measured by levels of anti-M. haemolytica IgG antibody and T-cell responses (IFN-γ and IL-17A) was better than that elicited by the commercially available adjuvant Quil-A, and had reduced reactogenicity. Taken together, the excellent immunological profile of p-C18Brar (3) and its ease and efficiency of synthesis makes it an attractive adjuvant for use in veterinary vaccines.

A synthetic Tn-BSA conjugate vaccine bearing chitotriose as built-in adjuvant

Chitotriose (CTS), the hydrolysate of chitosan, is readily soluble in water because of the shorter chain lengths of the oligomers and the free amino groups in the d-glucosamine units. In the current study, we report the synthesis of novel conjugate vaccine Tn-BSA-CTS with chitotriose as built-in adjuvant, along with an evaluation of the effect of adjuvant chitotriose (CTS). Immunological evaluations of the resultant conjugate vaccine revealed that Tn-BSA-CTS could provoke the highest titers of IgG antibodies (102,400). The Tn-BSA-CTS conjugate remarkably enhanced both humoral and cellular immunity. The obtained results demonstrate the potential of CTS as a novel vaccine adjuvant in the development of antitumor vaccine and the covalent linkage of tumor vaccine to CTS might be available strategy to increase the efficacy against cancer.