CD4-LYMPHOCYTES IN TRANSPLANTATION IMMUNITY .2. AUGMENTED REJECTION OF TUMOR ALLOGRAFTS BY MICE LACKING B-CELLS( AND B)

To test the importance of B lymphocytes in immunity to major histocomp atibility complex class I alloantigens, B cell-deficient mice were gen erated by reconstituting severe combined immunodeficiency mice, which lack functional B and T lymphocytes, with T cells or with both T and B cells. The reconstituted mice were challenged with a cancer that expr esses an MHC class I alloantigen at a low level and is susceptible to killing by CD8+ cytotoxic T lymphocytes. Tumors grew more slowly in an d were rejected more frequently by the mice lacking B cells. Understan ding the mechanism by which B cells suppress tumor allograft rejection may lead to new approaches for suppressing immune attack on transplan ted tissues.