RESUMO
A human Epstein-Barr virus (EBV)-positive lymphoblastoid B cell line, named BA-D10-4, produces a factor of a molecular mass less than 10 kDa that promotes cell proliferation of both BA-D10-4 cells and other human T or B lymphoid cell lines, either EBV-positive or -negative. The factor synergizes with higher molecular mass autocrine growth factors and makes both BA-D10-4 cells and B cell lines from Burkitt's lymphoma, but not cells from T cell leukemia, more responsive to interleukin-1 and interleukin-6. Therefore, this low molecular mass factor seems to be an autocrine growth factor per se and to have the characteristics of a competence factor.
Assuntos
Linfócitos B/metabolismo , Substâncias de Crescimento/biossíntese , Linhagem Celular Transformada , Cromatografia em Gel , DNA/biossíntese , Substâncias de Crescimento/química , Substâncias de Crescimento/farmacologia , Herpesvirus Humano 4 , Humanos , Interleucina-1/farmacologia , Interleucina-6/farmacologia , Peso MolecularRESUMO
Analysis of the growth requirements of Epstein-Barr virus (EBV)-transformed B lymphocytes shows that interleukin 1 and thioredoxin, a disulfide reducing enzyme, are able to induce a marked increase in DNA synthesis in the early phases of in vitro culture. By contrast, interleukin 6 induces a steady increase in DNA synthesis comparable to that observed with crude conditioned supernatant. Furthermore, EBV-transformed B cells exhibit a density-dependent responsiveness to autocrine growth factors, thus suggesting that growth regulation of EBV-transformed B cells might result from the interplay between different self-stimulating soluble factors and from the competence of the cells to respond to autocrine growth factors.