RESUMO
Peripheral blood lymphocytes from healthy, Epstein-Barr virus (EB-virus)-seropositive donors and from patients with acute Plasmodium falciparum malaria were tested for their cytotoxicity towards autologous EB-virus-infected B-cells using an in vitro regression assay. Of the 18 cultures from control donors, 88.8% showed the normal pattern of regression. Of the 20 malaria patients in the study, 40% failed to exhibit the normal pattern observed in the control group. Analysis of the lymphocyte subsets showed a high incidence of inverted CD4:CD8 ratios in the patient group due to an absolute rise in the CD8 population. This data suggests that the immunosuppressive effects of acute malaria extend to defective control over EB-virus. The relevance of the observations to the aetiology of EB-virus-associated, endemic Burkitt's lymphoma (eBL) is discussed.
Assuntos
Linfoma de Burkitt/etiologia , Infecções por Herpesviridae/complicações , Linfócitos/imunologia , Malária/complicações , Doença Aguda , Adolescente , Adulto , Animais , Criança , Infecções por Herpesviridae/imunologia , Herpesvirus Humano 4 , Humanos , Tolerância Imunológica , Contagem de Leucócitos , Ativação Linfocitária , Malária/imunologia , Pessoa de Meia-Idade , Plasmodium falciparum , Análise de Regressão , Linfócitos T Citotóxicos/imunologiaRESUMO
Culture supernatant from a human T-cell leukemia virus type I (HTLV-1)-infected cell line, DGA-1, contained a novel macrophage-activating factor (MAF). This MAF was antigenically and functionally distinct from interferon-gamma (IFN-gamma) and from granulocyte-monocyte colony-stimulating factor (GMCSF). Potential contaminants such as bacterial lipopolysaccharide (LPS), Mycoplasma spp, and HTLV-1 were not responsible for this MAF activity. The DGA-1 MAF was secreted constitutively and the cell line grew well in the absence of growth factors such as interleukin-2, mitogen, or antigen. This cell line should provide a good source of this MAF for further purification and characterization.