Effect of Antigen Density on Complement-Mediated Lysis, T-Cell-Mediated Killing, and Antigenic Modulation2

Publisher Website
Google Scholar
Abstract
The H-2 content of eight H-2d myeloma lines, two H-2d lymphomas, and the H-2d mastocytoma P815 was tested by quantitative absorption and direct binding of 125I-anti-H-2d. The cell lines were then compared for: 1) sensitivity to anti-H-2d and complement lysis, 2) sensitivity to allogeneic T-cell-mediated cytotoxicity, 3) antigenic modulation when cultured in excess anti-H-2d at 37° C, and 4) removal of anti-H-2 antibody from the cell surface in the presence of excess anti-H-2d. Generally, the cells behaved predictably from their surface antigen content. In complement-mediated cytotoxic assays, the myelomas and lymphomas showed a threshold effect with a given amount of surface antigen, below which complement-mediated killing was poor and above which killing was complete. PSIS, however, was poorly sensitive to complement-mediated lysis, though it had more H-2 antigen per unit area than any other cell line. For all of the lines, sensitivity to cell-mediated cytotoxicity showed a continuous progression: Cells with a high content of antigen tended to be better targets for cell-mediated lysis, whereas those with a lower antigen content tended to be poorer targets; those with an intermediate concentration varied considerably. Cell lines, poorly sensitive to antibody-complement lysis because of a low antigen density, were sensitive to T-cell lysis. Under modulating conditions, all the myelomas lost antibody from their surface to some degree; the extent of reduction of antibody paralleled their loss of sensitivity to complement-mediated Iysis.

This publication has 0 references indexed in Scilit: