The role of anti-asialo GM1 antibody-sensitive cells in the implementation of tumor-specific T cell-mediated immunity in vivo.

The present study deals with the role of cells sensitive to anti-asialo GM1 antibody treatment in T cell-mediated tumor cell eradication in vivo. Rabbit anti-asialo GM1 antiserum was injected into C3H/He mice. This treatment not only resulted in almost complete abrogation of natural killer (NK) cell activity but also produced a potent inhibiting effect on the generation of activated macrophage activity induced by inoculating Propionibacterium acnes (P. acnes). Such an immunodepressed state lasted for 20 days or more after 5 consecutive injections of anti-asialo GM1 antiserum. These anti-asialo GM1 antibody-treated C3H/He mice were used as recipients in Winn assays, in which the neutralizing activity of spleen cells immunized to syngeneic X5563 tumor cells was assessed. The results demonstrated that anti-X5563 immune spleen cells depleted of asialo GM1-positive cells by the in vitro treatment with anti-asialo GM1 antibody plus complement exhibited potent anti-X5563 tumor-neutralizing activity in antibody-untreated normal recipient mice. In contrast, the X5563-immune spleen cells depleted of asialo GM1+ cells failed to produce tumor protection in asialo GM1 antiserum-treated recipient mice. When T cell-deprived B cell mice were used as recipients in Winn assays, X5563 immune spleen cells depleted of asialo GM1+ cells exhibited or failed to exhibit tumor-neutralizing activity in asialo GM1 antiserum-untreated or -treated recipient B cell mice, respectively. These results indicate that the implementation of T cell-mediated in vivo protective immunity requires the participation of anti-asialo GM1 antibody-sensitive cells, but not necessarily the host's T cells.