PROLIFERATION AND IMMUNOGLOBULIN SECRETION OF LYMPHOBLASTOID CELL-LINES ARE DIFFERENTLY AFFECTED BY SOLUBLE CYTOKINES

The aim of our study was to investigate whether supernatant from lipop olysaccharide-activated monocytes (monocyte-factor) and/or cytokines c ould enhance secretion of human monoclonal antibodies specific to HLA antigens produced by Epstein-Barr virus lymphoblastoid cell lines (EBV -LCLs). In a low cell density culture system, the monocyte-factor sign ificantly stimulated cell growth of three monoclonal and two polyclona l EBV-LCLs while no enhancement of immunoglobulin production was obser ved. The enhancement of proliferation was completely neutralized by an antiserum to human IL-6 suggesting that IL-6 was required for the sti mulation of growth of LCLs. The effect of cytokines on proliferation s howed large variations among the cell lines, with IL-1 beta generally inducing the highest response. Of the cytokines tested, only IL-2 was able to enhance total immunoglobulin secretion due to the induction of a higher production of light chains. The specific anti-HLA activity w as slightly increased by IL-10 although this cytokine had no effect on total immunoglobulin concentration or proliferation.