The SARS-CoV-2 pandemic persists with global repercussions. Initial COVID-19 symptoms encompass pneumonia, fever, myalgia, and fatigue. The human immune system produces IgM and IgG antibodies in response to SARS-CoV-2. Despite previous research, a comprehensive understanding of the interplay between clinical manifestations and humoral immune responses remains elusive. This study aims to scrutinize this association. 134 COVID-19 patients were enrolled, and stratified into mild, moderate, and severe symptom groups. Serum IgM and IgG levels were assessed thrice at one-month intervals using ELISA. The findings reveal significant elevation in serum IgG levels in moderate compared to mild cases (P < 0.001). Additionally, IgG production was significantly heightened in severe cases compared to both mild (P < 0.0001) and moderate (P < 0.05) groups. IgM and IgG levels peaked initially and diminished over time. While anti-SARS-CoV-2 antibodies are expected to confer protection, the direct correlation between IgG levels and symptom severity may arise from delayed immune activation, resulting in an intense antibody response in severe cases. Given evidence linking delayed immune function with a dysregulated innate immune response, comprehensive data collection should encompass not only serum IgG and IgM, but also early measurement of type I interferons at symptom onset. This could provide a more thorough understanding of COVID-19 progression.

Laboratory-based case confirmation is an integral part of measles surveillance programmes; however, logistical constraints can delay response. Use of RDTs during initial patient contact could enhance surveillance by real-time case confirmation and accelerating public health response. Here, we evaluate performance of a novel measles IgM RDT and assess accuracy of visual interpretation using a representative collection of 125 sera from the Brazilian measles surveillance programme. RDT results were interpreted visually by a panel of six independent observers, the consensus of three observers and by relative reflectance measurements using an ESEQuant Reader. Compared to the Siemens anti-measles IgM EIA, sensitivity and specificity of the RDT were 94.9% (74/78, 87.4–98.6%) and 95.7% (45/47, 85.5-99.5%) for consensus visual results, and 93.6% (73/78, 85.7–97.9%) and 95.7% (45/47, 85.5-99.5%), for ESEQuant measurement, respectively. Observer agreement, determined by comparison between individuals and visual consensus results, and between individuals and ESEQuant measurements, achieved average kappa scores of 0.97 and 0.93 respectively. The RDT has the sensitivity and specificity required of a field-based test for measles diagnosis, and high kappa scores indicate this can be accomplished accurately by visual interpretation alone. Detailed studies are needed to establish its role within the global measles control programme.

To evaluate the dynamic changes of antibody levels in different groups after inoculation with the coronavirus disease 2019 (COVID-19) vaccine. The 1493 subjects who were tested for IgM and IgG against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at Qionglai Medical Center Hospital from June to October in 2021 were accepted for analyses of geometric mean titre (GMT) of IgG and IgM. The overall GMT of IgM and IgG in the population of Qionglai reached at a peak value at 1.497 (+3.810, −3.810) S/CO and 4.048 (+2.059, −2.059) S/CO in the second week, and then gradually decreased to 0.114 (+2.707, −2.707) and 1.885 (+1.506, −1.506) S/CO in the 11th–25th weeks, respectively. IgG was positive within 1 day, after that GMT increased continuously and peaked on the 13th day. There was a significant difference between male and female groups for titre of IgM during the prior 2 weeks and among three age groups for titre of IgG during the 2nd–3rd week after vaccination. The GMT level of IgG in the population vaccinated with the COVID-19 vaccine remained at a high level within 25 weeks and peaked on the 13th day, indicating that IgG could exist for a longer period and exhibiting positive SARS-CoV-2- defending effect.

Immune complexes (ICs) are found in canine visceral leishmaniasis (CVL) and interfere with the serum detection of antibodies. Dissociation of these monovalent complexes by dissociative enzyme-linked immunosorbent assay (ELISA) removes false-negative results and allows some characterization of antibodies and antigens. We studied the serology of dogs with suspected CVL in an endemic area, testing two Leishmania (Leishmania) [L. (L.)] <full form>infantum antigens. We analysed the presence of immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM) antibodies specific to promastigote soluble extract (PSE) and low-molecular weight glycans (glycan–bovine serum albumin (BSA) complex – GBC) by conventional and dissociative ELISA. Our results showed a significant fraction of IgA ICs (46.5% for PSE and 47.6% for GBC), followed by IgG ICs (10% for PSE and 23.5% for GBC). IgM ICs were more frequent for PSE (22.7%). Hypergammaglobulinaemia in CVL would be related to the presence of IgA and IgG ICs, resulting in deficient elimination of these antibodies. Our data confirmed the presence of ICs that can generate false-negative results in conventional serology. The production of IgA antibodies and the high frequency of blockade by glycan antigens suggest the active participation of this immunoglobulin and its ICs in the immunopathology of CVL, indicating a new path for further research.

The radiocarbon (14C) content of irradiated graphite is the most important problem for the management of Spanish irradiated graphite (Vandellós I NPP) as L&ILW, due to this material exceeding the maximum 14C inventory for the C.A. El Cabril repository. Therefore, the encapsulation of graphite in an impermeable matrix and making an appropriate waste form are indicated as potential management options to be studied. The conversion of the graphite to a long-term stable glass matrix, called IGM (impermeable graphite matrix), uses a long-term stable inorganic binder which additionally encloses the graphite pore system. The world’s first IGM samples made with irradiated graphite have been manufactured in CIEMAT facilities. The durability of the matrix is investigated in leaching experiments in deionized water and granitic bentonite water. The results show that ∼0.05% of 14C is leached. A species of organic carbon was found as formate and oxalate (∼10–1 mg/L). CO was detected as volatile specie in both media in the first leaching steps; for deionized water (∼3.101 mg/L) and in granitic bentonite water (ranging 1.101–3.101 mg/L). These low values demonstrated the durability of the IGM glass matrix for final disposal.

Blood and oral fluid (OF) samples were collected from 103 suspected measles cases between February and November 2010 during a nationwide measles outbreak in Zimbabwe. Siemens measles IgM enzyme immunoassay (EIA) on serum, Microimmune measles IgM capture EIA on OF, real-time haemagglutinin (H) gene PCR and nested nucleocapsid (N) gene PCR on OF were performed, confirming 75 measles cases. These samples were then used to evaluate a newly developed point of care test (POCT) for measles and determine its potential for identifying measles cases in outbreaks. After performing POCTs on OF samples, nucleic acid was extracted from the used test strips and the measles H and N genes amplified by RT–PCR. The sensitivity, specificity, positive and negative predictive values of the POCT for IgM in OF was 75·0% [95% confidence interval (CI) 63·4–84·5], 96·2% (95% CI 80·4–99·9), 98·2% (95% CI 90·3–100) and 58·1% (95% CI 42·1–73·0), respectively. The N gene sequences showed high level of agreement between original OF and corresponding POCT strips. Measles genotype B3 was identified in all cases. We conclude that the measles POCT has the potential to be used, at the point of contact, in outbreak situations and provide molecular characterization of the virus at a later date.

This study aimed to describe Toxoplasma gondii prevalence in Polish pregnant women and the incidence rates of congenital infections in their neonates observed between 2004 and 2012. Serological tests for T. gondii-specific IgG and IgM antibodies were performed on serum samples of 8281 pregnant women treated at the Polish Mother's Memorial Hospital Research Institute in Lodz. The yearly seroconversion rate for T. gondii IgG antibodies was estimated using a mathematical model to determine the dependency between age and prevalence. Mean prevalence of IgG antibodies between 2004 and 2012 in pregnant women was 40·6% [95% confidence interval (CI) 39·6–41·7] and increased with age with a yearly seroconversion rate of 0·8% (95% CI 0·6–1·0, P < 0·001). Assuming a T. gondii materno-fetal transmission rate of 30% gave an estimate of 1·80/1000 neonates as congenitally infected. The increased mean age (28·7 vs 26·7 years, P < 0·001) of pregnant women was probably the most important factor in abolishing the effect of falling prevalence rates.

Concentrations of IgA and IgM in milk from normal lactating cows were measured to determine whether they were affected by lactation number, lactation stage, daily milk production, milk composition and somatic cell score (SCS). A total of 284 Chinese Holstein cows showing no signs of mastitis were selected from more than 1600 cows from one farm. Concentrations of IgA and IgM in normal milk were determined by ELISA. Results revealed that average milk IgA and IgM concentrations were 235±11 and 32±3 μg/ml, respectively. IgA and IgM concentrations in milk were found to have an association with lactation number, stage of lactation, daily milk production and SCS. Both SCS and daily milk production were found to be strong significant (P<0·01) direct factors correlating to IgA concentration. Stage of lactation and SCS were found to be strong significant (P<0·01) direct factors correlating to IgM concentration.

Experiments were carried out to obtain additional data concerning the role of IgM antibodies, specific for the cuticular surface of the microfilariae (mf) of A. viteae, in clearing microfilaraemia from high-and low-responder mice infected by transplanted adult worms. Although BALB/c mice, which sustain a chronic microfilaraemia, produced IgM mf surface-specific antibodies, the binding to target mf was weak when compared to that of antibodies from the serum of the resistant C57BL/10 mice. Furthermore, antibodies from BALB/c mice were not as efficient as those from C57BL/10 mice in promoting the adherence of immune or control leukocytes to mf in vitro. Evidence is provided to show that mf shed surface bound antibody. Although the results do not establish conclusively the mechanism underlying the contrasting response phenotypes of C57BL/10 and BALB/c mice, they provide support for the involvement of antibody in controlling microfilaraemia and suggest that quantitative and qualitative differences in the amount and affinity of IgM antibody specific for the mf surface, together with the natural tendency of the mf to shed surface bound antibody at 37°C. may combine to allow the former strain to clear microfilaraemia efficiently whilst the latter sustains a chronic infection.

A total of 35 pigs aged 15 weeks old, and 21 pigs aged 8 weeks old were divided into 7 groups. Groups 1 and 2 were uninfected and challenge control groups, respectively. Groups 3 and 4 were infected weekly with 6 increasing doses of Ascaris suum eggs, and group 4 was additionally treated with pyrantel. Groups 5, 6, and 7 were immunized weekly with the 14, 42, or 97 kDa fractions from adult worms, respectively. Animals of groups 2–7 were challenged with 10 000 A. suum eggs 7 days after the last infection/immunization. Serum was sampled weekly and specific IgG1, IgG2, and IgM responses were measured. Pigs of groups 5, 6, and 7 showed high IgG1 and IgG2 responses especially against adult worms antigens, while infected groups had high IgG1 and IgM responses, especially against larva. The IgG1 responses were negatively correlated to the numbers of larvae in the lungs, and positively associated with the liver white spot numbers. There was a positive correlation between IgG2 and the numbers of white spots and lung larvae, while IgM was negatively correlated with these parasitological measures. These findings are discussed and it is suggested that acquired resistance against A. suum larvae is correlated with the induction of IgG1 and IgM, and not with IgG2, and that future vaccination protocols may focus on inducing the Th2 activity.