ABSTRACT
This chapter presents a short overview on interactions between maturing lymphocytes and the epithelial structures of the bursa and the thymus because these interactions form the basis for collaboration of mature lymphocytes. The first cells, representing macrophage/dendritic cell lineage, are responsible for the formation of the epithelial buds which, during the subsequent phase, are colonized by lymphoid precursors. The functional capacity of these cells has not been analyzed in detail, but the results demonstrate that chicken T-cell progenitors are able to differentiate in a xenogeneic thymus. The chicken major histocompatibility complex (MHC), originally described as a blood group system, consists of three loci: B-F (class I), B-L (class II), and B-G (class IV). The chapter carries out a series of experiments aiming at clarifying the mechanisms of tolerance induction in B-cell-chimeric chickens reconstituted with class 1 or class II incompatible bursa cells.
