DONORS AND RECIPIENTS ANTIGEN-PRESENTING CELLS COOPERATIVELY ENHANCE THE ALLOREACTIVE PROLIFERATION OF PERIPHERAL-BLOOD LYMPHOCYTES

Antigen-presenting cells (APC) play important roles in the alloreactiv e proliferation of T cells in vitro and in the allo-graft rejection in vivo. This work was aimed at establishing whether a co-operation of a ny kind occurs between donor's and recipient's APC during allo-reactio ns, and whether certain cell surface molecules, such as beta(2)-microg lobulin (beta(2)m) and human leucocyte antigens (HLA), are involved in such an interaction. The data herein reported show that the alloreact ive proliferation of peripheral blood lymphocytes (PBL) is markedly in tensified by a positive co-operation between donor's and recipient's A PC. Such a synergistic co-stimulatory action can be significantly hind ered by a monoclonal antibody aimed against beta(2)m while being not c hanged by monoclonal antibodies binding to either HLA-A-B-C or HLA-DR molecules. Hence, our preliminary results indicate that a positive int eraction between donor's and recipient's APC may be of importance for allo-graft rejection.