Production of autoantibodies associated with polyclonal activation in Yersinia enterocolitica 0:8-infected mice

Polyclonal lymphocyte stimulation is one of the immunomodulatory mechanisms induced by arthritogenic pathogens. In this study we examined the polyclonal activation potential of a virulent strain of Y. enterocolitica serotype O:8 (WA 2707+) and its plasmidless isogenic pair (WA 2707-). SPF Swiss mice were infected intragastrically and spleen cells were obtained on days 7, 14, 21, 28, 35 and 42 after infection. The number of cells secreting nonspecific immunoglobulins of IgG, IgM and IgA isotypes was determined by the ELISPOT technique. The presence of serum-specific antibodies was investigated by ELISA and the presence of autoantibodies by dot-blot assay. Although the patterns of infection of the two bacterial strains were almost the same, only the animals infected with the virulent strain presented clinical anomalies. Neither arthritic nor inflammatory signs were observed in the joints of the infected animals. The greatest activation observed was that of the nonspecific IgM-secreting cells, and their peak of secretion occurred between the 28th and the 42nd day after infection, for both strains of Y. enterocolitica O:8. Only the animals infected with the virulent strain (WA 2707+) produced IgG-specific antibodies in the serum, from the 28th day after infection. The serum of animals infected with either strain showed reactivity to all the autologous constituents tested, mainly on the 28th and 42nd day after infection. It was concluded that infection of mice with either the virulent strain of Y. enterocolitica O:8 or with its plasmidless isogenic pair resulted in the polyclonal activation of the splenic B lymphocytes including some autoreactive clones.

Isolation and molecular characterization of Brazilian turkey reovirus from immunosuppressed young poults

In this study, we investigated turkey reovirus (TReoV) in tissue samples from young birds, aged 15 days. RT-PCR for TReoV detected 3.3 % positive samples and TReoV was successfully isolated in Vero cells. Histological analysis of positive bursa of Fabricius (BF) revealed atrophied follicles and lymphocyte depletion. The number of CD8+, CD4+ and IgM+ cells was lower in infected BF. Phylogenetic analysis based on S3 gene showed that the Brazilian TReoV isolates clustered in a single group with 98-100 % similarity to TReoV strains circulating in the United States. This is the first indication that TReoV infection may be a contributing factor to immunosuppression in young birds.

Efeito do plasma rico em uréia na apoptose de neutrófilos de cães

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)