1988 Volume 32 Issue 3 Pages 283-292
BALB/c mice receiving allogeneic C3H/He or C57BL/6 spleen cells via portal venous (p.v.) route or a single administration of cyclophosphamide (Cy) were capable of rejecting the respective allogeneic C3H/He- or C57BL/6-derived tumor cells. In contrast, the combined treatment of p.v. inoculation with allogeneic lymphocytes and Cy administration abrogated the capability of rejecting allogeneic tumor cells. Such abrogation of alloreactivity was alloantigen-specific and associated with the suppression of potentials to generate delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte (CTL) responses to alloantigens. This was further substantiated by the inhibition of molecular mechanisms underlying anti-allo-DTH and -CTL responses. Thus, the above combined treatment led to the decreased production of lymphokines such as macrophage-activating factor (MAF) and interleukin 2 (IL2) following the stimulation with the relevant alloantigens. These results demonstrate that p.v. inoculation of allogeneic cells followed by a single administration of Cy results in the effective elimination of alloreactivity as verified by the suppression of cellular and molecular mechanisms of alloreactive responses.