Target cell lysis and IL-2 secretion by gamma/delta T lymphocytes after activation with bacteria.
Peripheral blood T lymphocytes from healthy donors were stimulated with Mycobacterium tuberculosis in vitro and afterward analyzed phenotypically. Marked expansion of the gamma/delta T cell population (3- to 21-fold) was observed in 15/21 donors 7 to 10 days after stimulation. In addition to M. tuberculosis, Mycobacterium leprae (six of eight) as well as the gram-positive bacteria, Staphylococcus aureus (two of six), group A streptococci (seven of nine), and Listeria monocytogenes (four of eight) augmented gamma/delta TCR expression in peripheral blood T cells of many donors. gamma/delta T lymphocytes expressed IL-2R and secreted IL-2 upon restimulation with M. tuberculosis. Stimulation with M. tuberculosis evoked specific cytolytic activities in gamma/delta T lymphocytes because: gamma/delta T cells lysed M. tuberculosis pulsed but not unpulsed targets; high concentrations of TCR delta 1 mAb facilitated killing of unpulsed target cells; and low doses of anti-TCR delta 1 mAb blocked killing of pulsed targets. Furthermore, gamma/delta T cells from four donors, after activation with M. tuberculosis or with group A streptococci, respectively, only lysed targets pulsed with the homologous agents, whereas in other donors some cross-reactivity was observed. We conclude that, upon contact with mycobacteria and perhaps other microorganisms, gamma/delta T cells are activated which contribute to immunity against infection via IL-2 secretion and specific target cell lysis.
Munk
M E
ME
Department of Medical Microbiology and Immunology, University of Ulm, FRG.
Gatrill
A J
AJ
Kaufmann
S H
SH
D000942:Antigens, Bacterial / Q000276:immunology; D002478:Cells, Cultured; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000378:metabolism*; D008089:Listeria monocytogenes / Q000276:immunology; D008213:Lymphocyte Activation; D009166:Mycobacterium leprae / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000145:classification* / Q000276:immunology / Q000502:physiology; D016692:Receptors, Antigen, T-Cell, gamma-delta; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013297:Streptococcus pyogenes / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D000942:Antigens, Bacterial; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D016692:Receptors, Antigen, T-Cell, gamma-delta; D015375:Receptors, Interleukin-2