Granules of human CD3+ large granular lymphocytes contain a macrophage regulating factor(s) that induces macrophage H2O2 production and tumoricidal activity but decreases cell surface Ia antigen expression.
CTL (cytotoxic T lymphocytes) and LGL (large granular lymphocytes) exocytose cytoplasmic granules on activation after recognition of their target, releasing granule-associated molecules. We have previously suggested that this process could release immunoregulatory molecules. In this study we investigated whether normal human LGL granules contained a factor regulating different macrophage activity. Human CD3+ LGL cells were generated by activating peripheral blood lymphocytes (PBL) for 10-12 days with recombinant human IL-2 (rhIL-2), and granules were isolated from disrupted cell homogenate by Percoll gradient fractionation. Solubilized granules were tested for macrophage-activating factor (MAF) activity in three different macrophage assays. When M-CSF-differentiated murine bone marrow-derived macrophages were incubated 9 hr with human LGL granules, they were fully activated to lyse the TNF-resistant P815 tumor cells. The granule-MAF showed a synergistic effect with rhIL-1 beta, rmTNF-alpha, and rmIFN-tau in the cytolytic assay. In addition, proteose-peptone-elicited murine peritoneal macrophages profoundly increased H2O2 production after activation with human LGL granules. However, unlike IFN-tau, no increase in peritoneal macrophage Ia antigen expression was detected after incubation with granules. Moreover, granule-MAF suppressed Ia induction by IFN-tau. These results confirm that human CD3+ LGL granules contain a molecule(s) capable of regulating macrophage function.
Roussel
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Department of Immunology, Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Canada.
Greenberg
A H
AH
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D017252:CD3 Complex; D003594:Cytoplasmic Granules / Q000737:chemistry; D003601:Cytotoxicity Tests, Immunologic; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D008222:Lymphokines / Q000502:physiology*; D008262:Macrophage Activation; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D009374:Neoplasms, Experimental / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D011994:Recombinant Proteins; D016176:T-Lymphocyte Subsets / Q000502:physiology / Q000648:ultrastructure; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology* / Q000648:ultrastructure; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1; D008222:Lymphokines; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D006861:Hydrogen Peroxide