[Antigenic sites implicated in tumour allograft enhancement].

Allo-immune sera were prepared by injecting CBA mice with spleen or thymus cells, or by two consecutive skin grafts of A/Jax origin. When absorbed 6 to 8 times on glutaradahyde treated A/Jax red blood cells (RBC), these sera lost all their haemagglutinating activity (anti- "SD" antibodies, predominantly H-2D) While their cytotoxic activities on A/Jax lymphocytes (anti-LD antibodies, perdominantly Ia, H-2IC) were partially preserved. Antibodies (anti-"XD") eluted form A/Jax RBC treated with an 0.5 M NaCl--HCL glycincing activity of these preparations was tested using SaI (A/Jax) grafts in CBA mice. Our results suggest that SD antigens are the main target of the enhancing effect. Further results obtained with DBA/2 anti-EL4 (C57Bl/6) sera confirmed this interpretation. Experiments performed with anti-idiotype and anti-recognition structure sera using tumor allograft targets, did not reveal any clear cut effect. Their relevance in tumor enhancement appears therefore doubtful.