title: Establishment of an interleukin 2-dependent T cell line derived from a patient with severe aplastic anemia, which inhibits in vitro hematopoiesis.
abstract: Circulating mononuclear cells from a patient developing severe aplastic anemia during the course of non-A, non-B hepatitis were found to be virtually entirely composed of in vivo activated suppressor T cells (Ia+T8+). These cells were used to establish a new permanent cell line, termed SMAA, by using phytohemagglutinin, Ebstein-Barr virus-transformed irradiated B cells, allogeneic irradiated peripheral blood mononuclear cells, and recombinant interleukin 2 to investigate the relationship of aplastic anemia-derived circulating T cells to bone marrow failure. SMAA cells, now in continuous culture for more than 9 mo, were shown to inhibit proliferation of purified myeloid progenitors and their differentiation into early and late appearing neutrophil and eosinophil colonies by 90%, whereas monocyte colonies were much less affected. Similarly, growth of erythroid colonies and bursts was almost completely inhibited, as was anti-mu-induced B cell proliferation and lectin-induced T cell proliferation. This inhibition of hematopoiesis was mediated by the release of a soluble factor that was sensitive to acid (pH 2), heat (56 degrees C), and trypsin. Monoclonal and polyclonal antibodies to interferon-gamma could abrogate the inhibitory effects of SMAA supernatant, but more than 10(4) neutralizing U/ml had to be added. The effects of SMAA could be duplicated by adding 10(4) U/ml of purified recombinant interferon-gamma to colony and proliferation assays. The concentration of interferon-gamma in SMAA supernatant was estimated to be greater than 3 X 10(3) National Institutes of Health reference U/ml by immunoradiometric assay. These results demonstrate that some patients with aplastic anemia have circulating T cells that are capable of prolonged in vitro secretion of interferon-gamma causing severe inhibition of in vitro hematopoiesis, and these cells can be expanded into permanent lines for studies on their regulatory properties.
mesh_terms: D000328:Adult; D000741:Anemia, Aplastic / Q000276:immunology* / Q000473:pathology; D000888:Antibodies, Anti-Idiotypic / Q000502:physiology; D001402:B-Lymphocytes / Q000166:cytology; D001854:Bone Marrow Cells; D002455:Cell Division; D002460:Cell Line; D002474:Cell-Free System; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003115:Colony-Stimulating Factors / Q000494:pharmacology; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology; D006801:Humans; D007075:Immunoglobulin M / Q000502:physiology; D007371:Interferon-gamma / Q000302:isolation & purification / Q000502:physiology*; D007376:Interleukin-2 / Q000502:physiology*; D008213:Lymphocyte Activation; D008297:Male; D010641:Phenotype; D010835:Phytohemagglutinins / Q000494:pharmacology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D003115:Colony-Stimulating Factors; D007075:Immunoglobulin M; D007376:Interleukin-2; D010835:Phytohemagglutinins; C044203:anti-IgM; D007371:Interferon-gamma