酵母細胞壁の抗腫瘍作用の免疫学的解析(第2報)マウスリンパ球におよぼす酵母細胞壁の影響

抄録

To investigate the role of lymphocytes on the antitumor activity of yeast cell wall (YCW) in mice, functional analysis of lymphocytes was made on the basis of the mitogenic response (³H-thymidine uptake) of mouse spleen cells to bacterial lipopolysaccharide (LPS ; a B cell mitogen) and Concanavalin A (Con A ; a T-cell mitogen). When normal mice and"tumor suppressed mice"(the mice in which tumor growth had been suppressed by the mixed injection of YCW and Ehrlich ascites tumor cells : EATC) were administered anti-thymocyte serum (ATS) or irradiated with X-rays, the tumor suppressive effect of YCW and their acquired resistance against tumor transplantation decreased. By the administration of ATS into these mice, the response of their spleen cells to Con A was reduced, but the response to LPS was not. X-Ray irradiation resulted in the reduction of mitogenic responses to both Con A and LPS. These results suggest that the tumor suppressive effect of YCW is mediated by T-cell function in mice and the acquired tumor resistance is also dependent on their T-cell function. The mitogenic activity of YCW was confirmed on cultured spleen cells in vitro. The spleen cells from the mice 2 days after the administration of YCW showed a marked enhancement of the mitogenic response to LPS. This fact indicates that YCW is capable of increasing B-cell population and/or the mitogenic responsiveness of B-cells in mouse spleen. The change of mitogenic response of spleen cells to LPS, Con A and Mitomycin-C treated EATC (MMC-EATC) during process of tumor suppression after the injection of mixture of YCW and EATC were investigated. Two days after the injection, the enhancement of mitogenic responses to LPS and MMC-EATC were observed. On 28 days, when the growth of tumor was mostly suppressed, the mitogenic response of their spleen cells to Con A was incresed. These finding suggest that YCW stimulates the B-cell at the early stage after the injection, and then converts its stimulation into T-cell in the advanced stage. The enhancement of T-cell function in the advanced stage be YCW may relate to its ability on anti-tumor activity.