Quantification of Anti-GP50, Anti-rT24H, and Anti-sTs18var1 Antibodies to Identify Viable Infection in Patients with Neurocysticercosis.

High levels of antibodies 6 months after COVID-19 vaccination in children with severe chronic diseases: A prospective longitudinal case series.

Measurement of serum antibody to subgingival bacterial species has been useful in discriminating possible periodontal pathogens and in assessing the host's immune response to subgingival species. An immunoassay system was developed to measure the level of serum antibody to multiple subgingival species in multiple serum samples on a single nitrocellulose membrane. The principle steps of the assay are the following: 1) binding of antigens from bacterial preparations and protein A in parallel lanes on nitrocellulose membranes; 2) incubation of known concentrations of human immunoglobulin as well as various dilutions of serum from patients in lanes perpendicular to the antigen lanes; 3) incubation of the membrane with a peroxidase-conjugated second antibody; 4) detection of positive reactions by enhanced chemiluminescence. Emitted light was captured on a photographic film in which the positive reactions appeared as squares at the intersections of antigens with appropriate antibody. Antibody was quantified using a laser densitometer to compare the signal intensity of unknown samples with the ones generated by known amounts of human immunoglobulin captured on the same membrane. The assay permitted simultaneous screening and/or quantification of antibody in as many as 45 serum samples against up to 45 bacterial species. The mean and standard error of the coefficients of variation for replicates within an assay averaged 7.3 +/- 2.3%. Coefficients of variation of the assay run on different days for serum antibody to a range of subgingival species averaged 10.1 +/- 2.1%. Checkerboard immunoblotting is a simple and rapid immunoassay to permit quantification and/or screening of antibody to multiple subgingival species or antigens in multiple serum samples.

Interplay of inflammatory markers and anti-SARS-CoV-2 antibodies in COVID-19 mortality: A prospective cohort study

The role of maternally acquired antibody to native type III polysaccharide of group B Streptococcus as a determinant of susceptibility for infant systemic infection was investigated. Sera from 111 acutely ill infants with type III group B streptococcal bacteremia and/or meningitis and their mothers, and cord sera from 45 healthy neonates and their mothers who had type III group B streptococcal vaginal colonization at delivery were studied. Sera from each of 111 acutely ill infants contained very low levels of antibody (less than 1.7 microgram/ml, median 0.4 microgram/ml), and a significant correlation with maternal levels was tested for early onset infection (median 0.6 microgram/ml; 4 = .76; P less than .01). Women whose infants remained well had antibody levels greater than 2 microgram/ml in their sera (73%) more often than those whose infants developed symptomatic infection (17%) (P less than .001), and the median level in their sera (12.6 microgram/ml) was considerably higher. Study of sera obtained during convalescence from 86 surviving infants indicated a poor antibody response to infection. In contrast, high levels of antibody were detected in sera from each of five convalescent women with postpartum bacteremia. These data extend earlier observations suggesting the correlation between low levels of type-specific antibody in serum and risk for systemic infection with type III strains of group B streptococci.

IgG antibodies to pre-erythrocytic antigens are involved in prevention of infection and disease in animal models of malaria but have not been associated with protection against disease in human malaria. Levels of IgG antibodies to circumsporozoite protein (CSP), liver-stage antigen type 1 (LSA-1), and thrombospondin-related adhesive protein (TRAP) were measured in 86 children in a malaria-holoendemic area of Kenya. The children were then monitored for episodes of clinical malaria for 52 weeks. Children with high levels of IgG antibodies to CSP, LSA-1, and TRAP had a decreased risk of clinical malaria (adjusted hazard ratio, 0.29; 95% confidence interval 0.10-0.81; P = .02), a lower incidence of clinical malaria (P=.006), protection from clinical malaria with a parasite level of > or =4000 parasites/microL (P= .03), and a higher hemoglobin level at enrollment (P= .009), compared with children with lower antibody levels. Protection against malaria morbidity was associated primarily with antibodies to CSP and LSA-1. Kenyan children with high levels of IgG antibodies to the pre-erythrocytic antigens CSP, LSA-1, and TRAP have a lower risk of developing clinical malaria than children without high levels of these antibodies. The decreased risk of clinical malaria may be mediated in part by prevention of high-density parasitemia.

Serum samples from 154 patients with nasopharyngeal carcinoma (NPC), 374 with other cancers, 1,000 normal controls from Government Employees' Clinic Center (GECC), and 3,642 individuals of various ethnic-dialect groups living in high-risk areas for NPC were collected and the concentration of antibodies to Epstein-Barr virus (EBV)-specific DNase activity was determined. Taking a serum sample where 1 ml will neutralize two or more units of the DNase activity as positive, 2-4 units as low level, 4-6 units as medium level, and more than 6 units as a high level of antibody, 90.3% of the NPC patients contained significant amounts of antibodies to EBV-specific DNase activity and most of those had high levels of the antibody. In contrast, only 11% of sera from patients with cancers other than NPC contained antibodies to EBV-specific DNase activity, and high levels were very rare (2.1%). The difference in positive rates between these two groups is highly significant according to the chi 2 test (P less than 0.001). The positive rate of this antibody in the control group (GECC) was 5.3% with 0.0%, 0.8%, and 4.5% having high, medium, and low levels of antibodies, respectively. Again, the difference in positive rates between the GECC group and the NPC group is statistically significant (P less than 0.001). Taken separately, the positive rates of anti-EBV DNase activity in the three high-risk groups were 11.7%, 13.0%, and 13.1%. No significant difference in age distribution for the levels of this antibody was observed in the control GECC group or the three high-risk groups. However, the positive rates of the three high-risk groups are more than twice those of the GECC group (11.7% approximately 13.1% vs 5.3%). This ratio coincides with the ratio of the probability of developing NPC in high-risk groups compared to that of the GECC group (also more than two times). The significance of this coincidence is discussed.

The serum antibody levels in Atlantic salmon ( Salmo salar L.) after vaccination with Vibrio salmonicida at different times during the smolting and early post-smolt period

A few neutralizing antibodies against human immunodeficiency virus-1 (HIV-1) envelope proteins have been shown to be highly effective at neutralizing different strains in vitro, and exist at very low levels in the sera of HIV-1-infected individuals. Based on our hypothesis that epitope vaccination may be a novel strategy for inducing high levels of antibodies against HIV-1, we prepared multiepitope vaccines using three neutralizing epitopes (GPGRAFY, ELDKWA and RILAVERYLKD) on HIV-1 envelope proteins. The PI [C-G-(ELDKWA-GPGRAFY)2-K] and PII (CG-GPGRAFY-G-ELDKWA-G-RILAVERYLKD) peptides were synthesized and conjugated to a carrier protein, bovine serum albumin (BSA). After vaccination, both the PI-BSA and PII-BSA multiepitope vaccines induced high levels of epitope-specific antibodies to the three neutralizing epitopes (antibody titre: 1 : 12,800-102,400). The recombinant glycoprotein 160 (rgp160) subunit vaccine induced strong antibody responses to rgp160, but only very weak epitope-specific antibody responses to the three epitopes. The epitope-specific antibodies were isolated from rabbit sera by single epitope-peptide-conjugated sepharose columns. A yield of 51 microg of epitope-specific antibodies/ml of serum (mean value) was obtained and identified to recognize these epitopes, while 0.35 microg of protein was isolated from 1 ml of pooled preserum by C-(ELDKWAG)4- or C-(RILAVERYLKD-G)2-K- and C-(GPGRAFY)4-sepharose columns. The levels of these epitope-specific antibodies induced in rabbits were much greater than 1 microg/ml, a level that is considered to confer long-term protection against some viruses. Moreover, these antibodies recognized the neutralizing epitopes on peptides and rgp41. Based on the fact that a very low level of ELDKWA epitope-specific antibodies exist in HIV-1-infected individuals, these results suggesting that synthetic epitope vaccines could induce high levels of multiepitope-specific neutralizing antibodies indicate a new strategy for developing an effective neutralizing antibody-based epitope/peptide vaccine against HIV-1.

Elephant endotheliotropic herpesviruses (EEHVs), of which eleven (sub)species are currently distinguished, infect either Asian (Elephas maximus) or African elephants (Loxodonta species). While all adult elephants are latently infected with at least one EEHV (sub)species, young elephants, specifically those with low to non-detectable EEHV-specific antibody levels, may develop fatal hemorrhagic disease (EEHV-HD) upon infection. However, animals with high antibody levels against EEHV(1A) gB, an immunodominant antigen recognized by antibodies elicited against multiple (sub)species, may also occasionally succumb to EEHV-HD. To better define which animals are at risk of EEHV-HD, gB and gH/gL ELISAs were developed for each of the Asian elephant EEHV subspecies and assessed using 396 sera from 164 Asian elephants from European zoos. Antibody levels measured against gB of different (sub)species correlated strongly with one another, suggesting high cross-reactivity. Antibody levels against gH/gL of different subspecies were far less correlated and allowed differentiation between these (sub)species. Importantly, while high gB-specific antibody levels were detected in the sera of several EEHV-HD fatalities, all fatalities (n = 23) had low antibody levels against gH/gL of the subspecies causing disease. Overall, our data indicate that (sub)species-specific gH/gL ELISAs can be used to identify animals at risk of EEHV-HD when infected with a particular EEHV (sub)species.

Diagnosis of human neurocysticerocosis in endemic countries: a clinical study in Honduras

57-Year-Old Man With Headache, Vomiting, and Gait Instability

BackgroundInfection by common viruses has long been discussed in the aetiology of a number of autoimmune diseases, including rheumatoid arthritis (RA). However, studies investigating this hypothesis in RA show conflicting results. These studies often lack well-matched control populations, and many do not include data on autoantibodies, genetic risk factors and other environmental factors, which are known to contribute to disease only in subgroups of patients. In the present study, we have therefore examined the role of Epstein-Barr virus (EBV), cytomegalovirus (CMV) and parvovirus B19 (B19) in RA aetiology, by analysing anti-viral antibodies in relation to anti-citrullinated protein antibodies (ACPA), smoking, HLA-DRB1 shared epitope (SE) alleles, and clinical parameters, in both RA patients and matched controls.MethodsAnti-viral antibodies were measured by ELISA in serum samples from 990 RA patients and 700 controls from the Swedish population-based Epidemiological Investigation of RA (EIRA) cohort. Data on ACPA, smoking, SE, inflammation (C-reactive protein) and disease activity score in 28 joints (DAS28) was obtained from the EIRA database. Fisher’s exact test, the chi-squared test, and the Mann-Whitney U test were used to calculate differences in anti-viral antibody frequencies and levels; unconditional logistic regression was used to determine the association of anti-viral antibodies with different RA subsets.ResultsAntibodies against all viruses were highly prevalent in EIRA, with no major differences detected between ACPA-positive RA, ACPA-negative RA and controls. However, both anti-B19 and anti-EBV IgG levels were significantly lower in ACPA-positive RA compared to controls, and there were significant interactions between low levels of anti-B19 and anti-EBV antibodies and SE in the development of ACPA-positive RA.ConclusionWe could not detect an association between RA and elevated anti-viral antibody levels, for any of the three common viruses, EBV, CMV or B19. On the contrary, our study demonstrated association between low anti-EBV/anti-B19 antibody levels and ACPA-positive RA, in particular when HLA-DRB1 SE was present. These data could potentially suggest that high anti-viral antibody levels would be protective against ACPA-positive RA. Further investigations are required to address the mechanisms behind these findings.

Background and Aims Kidney transplant recipients (KTRs) remain at increased risk for severe COVID-19 after vaccination, most likely due to an impaired immune response. However, the exact clinical impact of this impaired response remains unclear. Therefore we analysed the relationship between antibody levels after vaccination and the occurrence and severity of COVID-19 in a large cohort of KTRs. Method All KTRs, living in the Netherlands, who received COVID-19 vaccination were invited to participate in this observational cohort study. At approximately 28 days after the 2nd vaccination blood samples were obtained by a home-based finger-prick method and analysed for IgG antibodies against the receptor-binding domain of the SARS-CoV-2 spike protein (anti-RBD IgG). Participants were classified as either seronegative or seropositive using an anti-RBD IgG threshold of 50 BAU/mL. Participants who previously experienced COVID-19 were excluded. Primary endpoint was the incidence of COVID-19 from the moment the blood sample for anti-RBD IgG measurement was obtained until 6 months thereafter. Multivariable Cox and logistic regression analyses were performed to analyse which factors affected the occurrence and the severity (i.e. hospitalization and/or death) of COVID-19. Results In total 12,159 KTR were approached of whom 3,828 agreed to participate. In 2,885 subjects successful antibody measurement was performed after the 2nd COVID-19 vaccination. Among those, 1,578 (54.7%) became seropositive, whereas 1,307 (45.3%) remained seronegative. During a follow-up of 6 months, seropositivity was associated with a lower risk for COVID-19 incidence, also after adjusting for age, sex, socio-economic status and adherence to COVID-19 restrictions (HR 0.48 (0.27-0.86), p = 0.01). COVID-19 was also significantly less severe in seropositive as compared to seronegative participants (OR 0.14 (0.03-0.67), p = 0.01). When studied on a continuous scale, we observed a log-linear relationship between antibody level and risk for COVID-19 incidence (HR 0.52 (0.31-0.89) per tenfold higher anti-RBD IgG antibody level, p = 0.02). A threshold above which optimal protection was offered could not be detected. A similar association was found for COVID-19 severity. Conclusion In conclusion, antibody level after COVID-19 vaccination is associated in a log-linear relationship with the occurrence and severity of COVID-19 in KTRs. Therefore higher antibody levels, and not only reaching seropositivity, should be the aim of COVID-19 vaccination in KTRs. Immunosuppressed patients who have no or low antibody levels after vaccination should be offered repeat vaccinations, whether or not via alternative vaccination strategies, or passive immunization.

Introduction:Taenia solium is a common two-host parasitic cestode, residing in both humans (definitive) and pigs (intermediate). Invasion of this parasitic cyst into central nervous system leads to a condition known as neurocysticercosis (NCC). The World Health Organization (WHO) considers NCC as one of the “most neglected” tropical zoonotic diseases. The disease is presented with pleomorphic clinical manifestations, of which epilepsy is the most common. Diagnosis of NCC is carried out by serological tests and imaging methods. Only a few studies from Andhra Pradesh, Kerala, Tamil Nadu, and Pondicherry are available regarding the seropositive levels of NCC in South India.Materials and Methods:A descriptive analysis was carried out on NCC suspected patients attending outpatient or inpatient department of different clinics majorly from neurology, medicine, pediatrics, ophthalmology, and skin at Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, a tertiary care hospital in South India. A total of 391 patient samples (either serum or cerebrospinal fluid or urine) for 5 years from January 2011 to December 2015 were taken into the study. Serological investigations such as enzyme-linked immunosorbent assay and enzyme-linked immunoelectro transfer blot were performed for assessing the seropositivity levels of NCC.Results:The overall seropositive cases of NCC in the study population were found to be 32.5% of which positive male cases (59.1%) exceeding females (40.9%). The frequency of adult positive cases (77.2%) was more than that of pediatrics cases (22.8%) with an average of 30.9 years of age.Conclusions:NCC seropositive levels show an increasing trend with the study period. This necessitates a proper attention to the unnoticed spread of the parasitic disease, which affects the quality of life in the community. Quality screening and diagnostic strategy should be implied along with proper awareness for preventive measure practices have to be set up to reduce the impact of morbidity caused by NCC.

How Much Donor Human Leukocyte Antigen-Specific Antibody Is Too Much for a Renal Transplant?