Abstract
The immune response was analysed immunohistochemically in the chicken spleen after intravenous injection of alum-aggregated bovine serum albumin (A-BSA). From about 12 hr after primary injection, anti-bursa serum (ABS) positive lymphoblasts were observed in the periellipsoidal lymphatic tissue (PEL). One day later, ABS-positive lymphoblasts were also observed in the periarterial lymphatic tissue (PAL) and perivenous lymphatic tissue (PVL). The lymphoblasts became to form cell clumps and formed the germinal center (GC), suggesting that ABS-positive lymphoblasts in PEL might be origin cells of GCs. Two types of GCs appeared in the spleen after antigen injections. Type I GCs with many antigen presenting dendritic cells (DCs) were formed in the early stage after antigen injection, while type II GCs without antigen presenting DCs were formed in a later stage. The quantitative change of antibody producing cells (APCs) agreed with that of type I GCs but not that of type II GCs. Type II GCs were characterized by the antigen capture immediately after secondary injection, and by the appearance of many lymphocytes bearing anti-BSA antibody. The results suggested that type I and II GCs might have produced precursors of APCs and memory cells, respectively.
