Serum anti-S Research Articles

IgA quantification as a good predictor of the neutralizing antibodies levels after vaccination against SARS-CoV-2

BackgroundVaccination against COVID-19 was implemented very quickly, but the emergence of new variants that can evade the previous acquired immunological protection highlights the importance of understanding the mechanisms involved in the immune response generated after SARS-CoV-2 infection or vaccination. ObjectivesSince most of our knowledge on the humoral immunity generated against SARS-CoV-2 has been obtained from studies with infected patients before vaccination, our goal here was to evaluate seroconversion and its correlation with the titers of neutralizing antibodies (NAbs) in individuals who received the complete initial recommended vaccination schedule with three different vaccines. Study designWe analyzed serum IgG, IgA and total NAbs against the trimeric SARS-CoV-2 Spike (S) protein or its receptor binding domain (RBD) in blood samples collected from 118 healthy individuals without known previous infection, before and after receiving the first and the second dose of CoronaVac (n = 18), ChAdOx-1 (n = 68) or BNT162b2 (n = 32) vaccines. ResultsWe found that although IgG titers were high in all sera collected after the two doses of these vaccines, NAbs amounts varies among the groups. In contrast, serum NAbs concentrations were much more comparable to the IgA levels, indicating that these antibodies would have a major neutralizing capacity against SARS-CoV-2. ConclusionsAltogether our data suggest that quantification of serum anti-S or anti-RBD IgA, rather than IgG, may be a valuable tool to screen NAbs and may be considered for surveillance of vaccine coverage.

Low albumin level is more strongly associated with adverse outcomes and Staphylococcus aureus infection than hemoglobin A1C or smoking tobacco.

Postsurgical deep musculoskeletal infections are a major clinical problem in Orthopaedic Surgery. A serum-based nomogram, which can objectively risk-stratify patients, and aid surgeons in delineating infection risk associated with orthopedic surgical interventions, would be immensely helpful. Here, we constructed a multi-parametric nomogram based on serum anti-Staphylococcus aureus antibody responses, patient characteristics including demographics and standard clinical tests. This nomogram was formally tested in a prospective cohort study comparing 303 hospitalized patients with culture-confirmed S. aureus infection compared with a cohort of 223 healthy screened preoperative patients. Serum anti-S. aureus antibody responses, standard of care clinical tests, and patient demographic data were utilized to perform multivariate logistic regression analysis to quantify the presence of infection and adverse outcome using odds ratios (OR) and to assess predictive ability via area under the ROC curve (AUC). At enrollment, high anti-S. aureus IgG titers were predictive of infection. Remarkably, low serum albumin was found to be significantly associated with infection (OR = 479.963, 95% CI 61.59 - 3740.33, p < 0.0001) and this finding was surprisingly higher than BMI or HbA1c-associations. Combining all risk factors in the nomogram yielded a diagnostic AUC of 0.949 for predicting S. aureus infection. Our results indicate that a serum-based multi-parametric nomogram can be useful in diagnosing S. aureus infections, and importantly, malnourishment is significantly associated with these infections.

Detection of Campylobacter jejuni and Salmonella typhimurium in chicken using PCR for virulence factor hipO and invA genes (Saudi Arabia).

Campylobacter jejuni and Salmonella typhimurium are the leading causes of bacterial food contamination in chicken carcasses. Contamination is particularly associated with the slaughtering process. The present study isolated C. jejuni and S. typhimurim from fifty chicken carcass samples, all of which were acquired from different companies in Riyadh, Saudi Arabia. The identification of C. jejuni was performed phenotypically by using a hippurate test and genetically using a polymerase chain reaction with primers for 16S rRNA and hippurate hydrolase (hipO gene). For the dentification of S. typhimurim, a serological Widal test was carried out using serum anti-S. typhimurium antibodies. Strains were genetically detected using invA gene primers. The positive isolates for C. jejuni showed a specific molecular size of 1448 bp for 16S rRNA and 1148 bp for hipO genes. However, the positive isolates of the invA gene exhibited a specific molecular size at 244 bp using polymerase chain reaction (PCR). Comparing sequencing was performed with respect to the invA gene and the BLAST nucleotide isolates that were identified as Salmonella enterica subsp. enterica serovar typhimurium strain ST45, thereby producing a similarity of 100%. The testing identified C. jejuni for hippuricase, GenBank: Z36940.1. While many isolates of Salmonella spp. that contained the invA gene were not necessarily identified as S. typhimurim, the limiting factor for the Widal test used antiS. typhimurum antibodies. The multidrug resistance (MDR) of C. jejuni isolates in chickens was compared with the standard C. jejuni strain ATCC 22931. Similarly, S. typhimurium isolates were compared with the standard S. typhimurium strain ATCC 14028.

Conversion of serum anti-Schistosoma japonicum antibodies detected by immunological tests following treatment with praziquantel: a meta-analysis

To evaluate the conversion of serum antibodies against Schistosoma japonicum in humans and livestock detected by immunological tests following treatment with praziquantel. The studies pertaining to serological tests of schistosomiasis japonica published from 1991 to 2020 were retrieved in electronic databases, including Chinese National Knowledge Infrastructure, WanFang Data, PubMed and ScienceDirect. Data were extracted from included studies. The publication bias was assessed with funnel plots using the software RevMan version 5.3, and the conversion of antibodies against S. japonicum was evaluated through meta-analysis. A total of 40 publications were included in the final meta-analysis, consisting of 33 Chinese publications and 7 English publications, and all immunological tests were performed with indirect hemagglutination test (IHA) and enzyme-linked immunosorbent assay (ELISA). Pooled analysis showed that the negative rates of serum anti-S. japonicum antibody were 45.36% [95% confidential interval (CI): (43.96%, 46.76%)] and 20.83% [95% CI: (19.69%, 21.97%)] detected by ELISA and IHA within 6 months post praziquantel treatment, 62.95% [95% CI: (61.59%, 64.31%)] and 55.61% [95% CI: (54.21%, 57.01%)] within 6 to 12 months after treatment and 85.92% [95% CI: (84.94%, 86.90%)] and 86.90% [95% CI: (85.95%, 87.85%)] over 12 months after treatment, respectively. The negative rate of the serum anti-S. japonicum antibody by IHA and ELISA increased with the time of post-treatment with praziquantel. The overall negative rates of anti-S. japonicum antibody detected by IHA and ELISA are low within 12 months post praziquantel treatment. However, a high negative rate of anti-S. japonicum antibody is detected if there is no new contact with infested water after 12 months of praziquantel treatment.

Strongyloides stercoralis infection in patients with systemic lupus erythematosus: diagnosis and prevention of severe strongyloidiasis.

Strongyloides stercoralis infection is usually chronic and asymptomatic and may persist undiagnosed for decades. However, in immunocompromised individuals, the infection can cause hyperinfection and dissemination. Therefore, early diagnosis is essential to prevent severe forms of strongyloidiasis. The aims of this study were: (i) to evaluate the frequency of S.stercoralis infection in patients with systemic lupus erythematous (SLE) and (ii) to estimate specific immunoglobulins G (IgG) and E (IgE) production using an enzyme-linked immunosorbent assay (ELISA) method. Seventy-five SLE patients treated with prophylactic anthelmintic therapy were evaluated using the spontaneous sedimentation (SS), Baermann-Moraes (BM) and agar plate culture (APC) methods. Serum anti-S.stercoralis IgG and IgE antibodies were measured by ELISA. Using parasitological methods, the frequency of intestinal parasites was 10.7%, whereas the frequency of S.stercoralis infection was 1.3%. The sensitivity of the ELISA to detect anti-S.stercoralis IgG and IgE was 80% and 76.9%, respectively. Both assays presented the same specificity of 96.7%. The frequency of anti-S.stercoralis IgG and IgE was 16% and 28%, respectively. Six patients were positive for both antibodies. Diagnostic approaches using high-sensitivity parasitological methods and the detection of specific antibodies are essential for the diagnosis of strongyloidiasis in immunocompromised patients. Early detection of infection can alter the course of the disease via appropriate treatment, preventing the occurrence of severe strongyloidiasis.

Anti-S. typhi Vi IgG levels in children with and without typhoid vaccinations

Background Typhoid fever is endemic to Indonesia, with an annual incidence of 13/10,000 people. Vaccination has been shown to be an effective method to prevent typhoid fever. Of several vaccine types, the polysaccharide Vi vaccine is the most commonly used typhoid vaccine in developing countries. Results of previous studies remain inconclusive on the necessity of revaccination every 3 years.Objective To compare the mean serum anrioody titers of anti-S. typhi Vi IgG and the proportion of children with protective antibody levels between children with and without typhoid Vi vaccination.Methods We conducted a cross-secrional study at Tuminring District, 11anado from June to September 2012. Data was analyzed using independent T-test and Fisher's test. Serum anti-S. typhi Vi IgG levels were measured by enzyme-linked immunosorbent assay (ELISA) method.Results Seventy-six subjects were divided into two groups: 38 children who had received the typhoid Vi vaccination more than 3 years prior to this study and 38 children who never had typhoid vaccinations as a control group. No statistically significant difference in age and gender was found between the two groups. The mean serum anti-Vi IgG level was 0.55 ug/mL (SD 0.58; 95%CI 0.36 to 0.74) in the vaccinated group, significantly higher than that of the control group [0.31 ug/mL (SD 0.12); 950/£1 0.17 to 0.44; P􀂥0.0381. The proportion of children with protective antiNi antioody level was higher in the vaccinated group (23.7%) than in the control group (10.5%), howevet; this difference was not statistically significant (P=0.128).Conclusion The mean serum anti-S. typhi Vi IgG antibody level in children who had been vaccinated more than 3 years prior to the study is higher than in children who had never received typhoid vaccinations. Nevertheless, the mean antibody titers are generally non-protective in ooth groups. Also, the proportion of children with protective antibody levels is not significantly different between the two groups.

Influence of horn flies (Haematobia irritans) on teat skin condition, intramammary infection, and serum anti-S. aureus antibody titres in holstein heifers

Staphylococcus aureus remains a major mastitis-causing pathogen in growing dairy heifers, resulting in damage to developing milk secretory tissue. The purpose of this study was to evaluate the role of horn flies as vectors in the spread of S. aureus among dairy heifers immunized with a S. aureus bacterin. We analyzed the prevalence of mastitis among quarters, evaluated teat skin condition (as a result of biting flies) prior to and after insecticide administration, and measured serum anti-S. aureus antibody titres monthly after vaccination. Response to S. aureus immunization was poor; however, titres increased 2- to 3-fold during the period when fly populations increased drastically and teat skin condition worsened, especially front quarter teat condition. Presence of flies and the resulting teat lesions were associated with a high level of S. aureus mastitis. Use of an insecticidal pour-on reduced fly populations and healed teat lesions, but existing cases of mastitis required antibiotic therapy.

Serum IgA reactivity against GroEL ofStreptococcus sanguinisand human heterogeneous nuclear ribonucleoprotein A2/B1 in patients with Behçet disease

Infectious agents, especially Streptococcus sanguinis and herpes simplex virus, have long been postulated as major triggering factors for Behçet disease (BD).To identify an anti-S. sanguinis antigen reacting with serum IgA antibody in patients with BD.We detected a target protein by proteomics analysis and evaluated serum IgA reactivity of 100 patients with BD against the identified streptococcal target protein and human heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1. Homologous epitope sequences between the streptococcal target protein and human hnRNP A2/B1 were also evaluated.Four protein bands were detected by immunoprecipitation, and chaperonin GroEL was identified by a proteomics analysis. Reactivity of serum IgA against recombinant S. sanguinis GroEL was detected in 77 of 100 patients with BD (77%) and in 21 of 70 healthy controls (30%). In addition, reactivity of serum IgA against human recombinant hnRNP A2/B1 was seen in 79 of 100 patients with BD (79%) and in eight of 70 healthy controls (11%). Among the eight distinctive epitopes with significant homology between S. sanguinis GroEL and human hnRNP A2/B1, the serum IgA reactivity of patients with BD was markedly higher with epitope 3 (hnRNP A2/B1 peptide 33-46 and GroEL peptide 57-70) and epitope 6 (hnRNP A2/B1 peptide 177-188 and GroEL peptide 347-358).We identified an S. sanguinis GroEL protein as a target of serum anti-S. sanguinis IgA antibody reactivity in patients with BD. In addition, patients with BD exhibited serum IgA reactivity against homologous epitope regions between S. sanguinis GroEL and human hnRNP A2/B1.

Local and systemic immune responses to combined Vibrio cholerae CVD103-HgR and Salmonella typhi Ty21a live oral vaccines after primary immunization and reimmunization

The local and systemic antibody responses elicited following concomitant primary immunization and reimmunization with the live oral attenuated Vibrio cholerae CVD103-HgR and Salmonella typhi Ty21a vaccine strains were determined in healthy adult volunteers. A more pronounced serum vibriocidal antibody response was generated after primary immunization compared to reimmunization 2.5 or 3.5 yr later. The seroconversion rate (≥4-fold rise over baseline) was 81% subsequent to primary immunization versus 57% (p=0.018) and 65% (p=0.639) upon reimmunization at 2.5 and 3.5 yr, respectively. A similar trend was observed for serum anti-S. typhi lipopolysaccharide (LPS) antibodies. After primary immunization, 48% of subjects manifested a significant rise in coproantibody levels to V. cholerae LPS while 60% did so for cholera toxin (CT). Upon reimmunization, the response rate for LPS ranged from 38% at 2.5 yr to 56% at 3.5 yr (p>0.05), while that for CT varied from 31% (p=0.007) to 50% (p=0.541) at 2.5 and 3.5 yr, respectively. The anti-S. typhi IgA coproantibody response rate was 70% subsequent to primary immunization versus 47% at 2.5 yr (p=0.021) and 63% at 3.5 yr (p=0.77).

Safety and immunogenicity of a live oral bivalent typhoid fever (Salmonella typhi Ty21a)-cholera (Vibrio cholerae CVD 103-HgR) vaccine in healthy adults

The safety and immunogenicity of the live oral attenuated vaccine strains vibrio cholerae CVD 103-HgR and Salmonella typhi Ty21a were evaluated alone or in a combined bivalent formulation in four groups composed of 185 healthy European adults. All presentations were well tolerated. The serum anti-S. typhi lipopolysaccharide immunoglobulin G and immunoglobulin A antibody responses were comparable for all groups (66 to 72% seroconversion). The serum vibriocidal antibody seroconversion rate ranged from 78 to 92.5% (P > 0.05) among the groups. However, the peak and geometric mean vibriocidal antibody titers were significantly higher (P < 0.005) in the groups which received the bivalent formulation along with two doses of Ty21a than in the group which received CVD 103-HgR followed by two doses of killed Escherichia coli K-12 placebo. The ingestion of a placebo shortly after CVD 103-HgR may have suppressed the magnitude of the immune response. These findings demonstrate the feasibility of producing multivalent live oral attenuated vaccines.

Immunoglobulins in the hyperimmunoglobulin E and recurrent infection (Job's) syndrome. Deficiency of anti-Staphylococcus aureus immunoglobulin A.

Patients with the hyperimmunoglobulin E and recurrent infection syndrome (HIE) characteristically have frequent skin and respiratory infections caused by Staphylococcus aureus. We have developed a set of enzyme-linked immunosorbent assays that use whole S. aureus (Wood's strain) immobilized on 0.22-micrometers filters and highly specific, affinity-purified enzyme conjugates of goat anti-human IgE, anti-human IgD, anti-human IgG, anti-human IgA, and anti-human IgM. These reagents were used to determine S. aureus-specific immunoglobulin (Ig) levels. As previously published, 10 patients with HIE had markedly higher levels of anti-S. aureus IgE than did 5 patients with eczema and recurrent superficial S. aureus infections (P less than 0.001). The HIE patients were also found to have a deficit of anti-S. aureus serum IgA as compared with 12 normal subjects, 12 patients with chronic granulomatous disease, 5 patients with chronic eczema and recurrent superficial S. aureus infections, and 3 patients with the Chediak-Higashi syndrome (P less than 0.01 for each comparison). In addition the HIE patients had an excess of anti-S. aureus IgM as compared with normal subjects (P less than 0.01). An expected excess of anti-S. aureus IgG was absent. These abnormalities cannot be explained by variations of total serum Ig levels or by a general inability to produce antigen-specific IgA because levels of naturally occurring IgA antibody against Escherichia coli lipopolysaccharide and the antigens of the pneumococcal vaccine are normal. Parotid saliva from patients with HIE contained less salivary IgA per milligram of protein (P less than 0.01) and less salivary anti-S. aureus IgA per milligram of protein (P less than 0.05) than did normal controls. The incidence of infection at mucosal surfaces and adjacent lymph nodes correlated inversely with serum anti-S. aureus IgA (r = -0.647, P = 0.034), serum anti-S. aureus IgE (r = -0.731, P = 0.016), total serum IgE (r = -0.714, P = 0.020), and total serum IgD (r = -0.597, P = 0.049). These findings are evidence of a previously undescribed immunoregulatory defect in patients with HIE, which may contribute to the increased susceptibility to infection in this syndrome.