Anti-receptor anti-MHC cytotoxic T lymphocytes: their role in the resistance to graft vs host reaction.

Specific resistance to local graft vs host reaction (GvHR) observed in F1 hybrids pretreated s.c., i.p., or i.v. with parent strain spleen cells has been explained as being due to cytotoxic cells induced in these pretreated F1 hybrids and directed against cells bearing receptors that recognize the major histocompatibility complex (MHC) alloantigens of the opposite parent strain (anti-receptor anti-MHC cytotoxic T lymphocytes; CTL). These anti-receptor anti-MHC CTL, however, have never been detected directly in popliteal lymph nodes (PLN), which develop a specific resistance to GvHR. In this paper, we describe the detection of anti-receptor anti-D2 cytotoxic activity in both right and left PLN of B6D2F1 hybrids injected s.c. in the right footpad only with B6 spleen cells. This cytotoxic activity appears 4 days after the injection of B6 cells and diminishes by day 7. It is mediated by a Thy-1+, L3T4-, Lyt-2+ cell of B6D2F1 origin and induced by the injection of either Thy-1+L3T4+Lyt-2- or Thy-1+L3T4-Lyt-2+ B6 spleen cells. The anti-receptor anti-D2 CTL activity is not observed in PLN of B6D2F1 hybrids pretreated i.p. or i.v. with B6 spleen cells. Our results demonstrate that anti-receptor anti-MHC CTL can fully explain the specific resistance to GvHR induced by the s.c. pretreatment of F1 hybrids with parent strain spleen cells. Their role, however, in the resistance to GvHR observed in F1 hybrids i.v. or i.p. pretreated is far from being entirely proven.