Chicken B lymphocyte differentiation: bursal microenvironment and differences in ontogeny between normal and SPF birds.

Abstract

The avian bursa of Fabricius provides a unique model for the investigation of B lymphocytopoiesis since its involvement in this process is essential (Grossi et al., 1976; Eerola et al., 1982; Boyd et al., 1983). This organ contributes significantly to the clonal expansion of B cells, the majority of follicles being derived from 2-5 stem cells committed prior to proliferation within the bursa (Pink et al., 1985b; Ratcliffe et al., 1986). Close to hatching, these differentiated cells acquire the ability to migrate to peripheral tissues (Boyd and Ward, 1984). A common precursor to the follicular cortex and medulla has been described (Pink et al., 1985a) and it appears less differentiated lymphocytes occur in the cortex (Boyd and Ward, 1978). It is also established that the bursal epithelium is receptive to stem cell influx between 8 and 15 days of embryogenesis (Le Douarin, 1986).