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Identification and Characterization of Two Distinct Bursal B-Cell Subpopulations Following Infectious Bursal Disease Virus Infection of White Leghorn Chickens

Petkov, Daniel I., Linnemann, Erich G., Kapczynski, Darrell R., Sellers, Holly S.
Avian diseases 2009 v.53 no.3 pp. 347
chickens, White Leghorn, bursa of Fabricius, infectious bursal disease, Infectious bursal disease virus, vertebrate viruses, immunoglobulin M, B-lymphocytes, phenotype, spleen, signs and symptoms (animals and humans), major histocompatibility complex, viral antigens, vaccination, temporal variation, immunoglobulin A, immunoglobulin G, gene expression
Infectious bursal disease virus (IBDV) is an immunosuppressive virus which primarily infects IgM B-cells in the bursa of Fabricius. Flow cytometric analysis was used to phenotype B-cell populations in the bursa and spleen following IBDV infection. In the bursa, two IgM B-cell subpopulations, designated as A and B, were identified based on cell size and granularity. While both subpopulations differentially expressed IgM and Bu-1b surface markers, both groups displayed major histocompatibility complex class II surface antigens at equal levels. Following IBDV challenge of nonvaccinated birds, the B subpopulation was significantly reduced between 7 and 21 days postchallenge compared to either nonchallenged birds or vaccinated-challenged birds. However, the reduction of subpopulation B in the bursa, following IBDV exposure, did not reduce the levels of total serum IgA, IgG, and IgM, nor did it affect IgG and IgA B-cells in the spleen. Phenotypic analysis of the subpopulations identified differential expression of Lewis(x), IgM, Bu-1b, and MUI78 surface antigens between the subpopulations. Overall, these are the first studies to identify two distinct IgM B-cell subpopulations in the chicken bursa, and the first to describe the decrease in the IgM B-cell population relative to IgA and IgG B-cells following IBDV infection.