Immunoblast formation by recirculating and non-recirculating rat lymphocytes cultured in diffusion chambers.

Abstract

Rat lymphocytes of two types were obtained and their reactions to antigens studied in an in vivo situation. Lymphocytes which recirculate between blood and lymph (RL) were collected from a thoracic duct catheter, and non‐recirculating lymphocytes (NRL) were separated from the blood of rats that had been depleted of thoracic duct lymph for up to six days. The cells were suspended in diluted mouse plasma and cultured for three or five days in diffusion chambers. The cell‐impermeable chambers were implanted into the peritoneal cavities of rats, mice, or irradiated mice. The proliferation, differentiation and death of the cells were quantified by total and differential cell counting and by liquid scintillation measurement and radioautographic evaluation of 3H‐thymidine incorporating cells.Lymphoid cell populations contained immunoblast precursor cells in numbers roughly proportional to the content of RL. Even after prolonged lymph drainage, however, some blast cells were still detected among cultured blood leucocytes. The presence of macrophages did not appear to influence the formation of blast cells. A slight morphological difference between typical RL and NRL has been observed, the latter cells having some monocyte features.