PROPERDIN, A POSITIVE REGULATOR OF COMPLEMENT ACTIVATION, IS EXPRESSED IN HUMAN T-CELL LINES AND PERIPHERAL-BLOOD T-CELLS

Properdin plays an important regulatory role in the activation of the complement system. Here we report the biosynthesis of properdin in fou r different human T cell lines and in T cells purified from peripheral blood. Cell sorting experiments, in conjunction with Northern blottin g, showed that both CD4- and CD8-bearing populations of T cells have t he potential to synthesize properdin. The functional activity of prope rdin secreted from these T cell lines was determined in a hemolytic as say. In view of the numerous ways in which complement activation may i nfluence cellular immune response, the present results indicate, for t he first time, a possible interaction between the complement and the T cell system.