The effect of immunization with a 14-kDa streptococcal antigen on primate T cell and B cell responses

Endocrine disruption by PFAS: A major concern associated with legacy and replacement substances

Perand poly-fluorinated alkyl substances (PFAS) have been used for decades in a great variety of processes and products by virtue of their exceptional properties, versatility and chemical stability. Nevertheless, it is increasingly recognized that these substances can represent a serious hazard to human health and living organisms due to their persistence, long-range transport potential and tendency to accumulate in biota. For this reason, some efforts have been made across the EU to identify alternative molecules, with a shorter carbon chain and theoretically safer profile, that might replace the previous generation of legacy PFAS. Unfortunately, this strategy has not been entirely successful and serious concerns are still posed by PFAS in different human populations. Among others, an emerging aspect is represented by the adverse effects that both legacy and alternative PFAS can exert on the human endocrine system, with respect to vulnerable target subpopulations. In this review we will briefly summarize PFAS properties, uses and environmental fate, focusing on their effects on human reproductive capacity and fertility, body weight control and obesity as well as thyroid function.

Identification and characterization of IgA and Vicia villosa-binding T cell subsets in rheumatoid arthritis

Autoimmunity may be due to augmentation of immune responses by human CD8 cells which bind the lectin Vicia villosa (VV). We have investigated T cells in rheumatoid arthritis (RA) by double immunofluorescence flow cytometry, in order to assess VV-binding CD8 and CD4 cells from the peripheral blood and synovial fluid. A significant increase in CD8+VV adherent (P less than 0.0001) and CD4+VV adherent cells (P less than 0.001) was found in synovial fluid, as compared with peripheral blood from patients with RA. A significant increase in VV-binding CD8+ or CD4+ cells was, however, not found in the blood of patients with RA, as compared with controls. We suggest that the lack of VV-binding T cells separated from blood, in contrast to those from synovial fluid, may be due to an inhibiting agent expressing N-acetyl D-galactosamine. Indeed, IgA1 is rich in N-acetyl D-galactosamine, it inhibits VV binding to T cells and is significantly bound to CD8 cells (P less than 0.001). The IgA1 was then characterized and in about half the patients J chains and secretory component was found, suggesting that the IgA1 is of the polymeric and secretory variety. IgA bound to the T cells engaged the Fc alpha receptors and a significant decrease in the Fc alpha receptors was found in CD8 cells (P less than 0.0001) and CD4 cells (P less than 0.01). Desorption studies were then carried out on CD8 and CD4 cells which showed that a loss of cell-bound IgA1 was associated with an increase in VV binding. Conversely, adsorption of IgA to T cells was associated with a loss in VV binding. The results suggest that the failure of VV binding to CD8+ and CD4+ cells from peripheral blood of patients with RA can be ascribed to cell-bound IgA1. Cytophilic IgA1 may inhibit the function of CD8+VV binding cells, thereby preventing augmentation of the systemic immune response, consistent with the lack of extra-articular disease in these patients with RA.

Separation and characterization of a 14,000-dalton cyanogen bromide-generated peptide from a 185,000-dalton streptococcal antigen

The cell surface streptococcal antigen (SA) (185,000 molecular weight [185K SA]) was isolated from Streptococcus mutans and digested with cyanogen bromide. Three major products with molecular weights of 100,000, 50,000, and 14,000 appeared within 1 h of digestion. Time course studies of digestion by polyacrylamide gel electrophoresis showed maximal intensity of the 14K band after 8 h. However, other bands appeared as well, notably 70K and 20K bands. Several bands were eluted from the gels, and their antigenicity was studied. They reacted with antisera to the native 185K SA I/II, as well as with those to the SA I and SA II antigens, though antibody binding by radioimmunoassay was significantly lower than that with the native SA. The 14K SA was identified on Western blots (immunoblots) with anti-SA I/II, I, and II antisera. The digested SAs were then tested for their immunogenicity by injecting CBA mice with the separated SA mixed in complete Freund adjuvant. Whereas the unseparated cyanogen bromide-treated SA and separated 70K and 20K SAs were immunogenic, the 14K SA failed to elicit serum antibodies. Further investigation of the 14K SA revealed that although it is apparently not immunogenic, it can induce a primary antibody response in mice when followed by the native 185K SA and a secondary response when mice are immunized first with the 185K SA.