Naive human T cells develop into Th1 or Th0 effectors and exhibit cytotoxicity early after stimulation with Leishmania-infected macrophages.
Studies of human disease suggest that naturally acquired immunity is the predominant outcome of Leishmania infection. Normally protective immune mechanisms activated during asymptomatic or self-healing infections may be minimal in patients who develop disease. To explore early immune responses, an in vitro model of human Leishmania infection was developed in which naive T cells were sensitized with Leishmania-infected macrophages. An analysis of Leishmania-specific cytokine production by these T cell lines revealed that most individuals developed Th1 or Th0 responses early after infection. Infected macrophages from Th1 responders produced interleukin-12. Th0 responders who produced little or no endogenous interleukin-12 could be converted to the Th1 phenotype by addition of interleukin-12 during priming. Finally, infection-sensitized T cells specifically lysed Leishmania-infected macrophages. Thus, this in vitro model system can be used to delineate protective human immune responses against Leishmania induced early after infection.
Russo
D M
DM
Department of Microbiology, Meharry Medical College, Nashville, Tennessee 37208, USA.
Chakrabarti
P
P
Burns
J M
JM
D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis*; D003602:Cytotoxicity, Immunologic; D006801:Humans; D018664:Interleukin-12 / Q000096:biosynthesis / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology; D007891:Leishmania / Q000276:immunology*; D008264:Macrophages / Q000166:cytology / Q000276:immunology* / Q000469:parasitology*; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology*; D018417:Th1 Cells / Q000166:cytology / Q000276:immunology*
D016207:Cytokines; D007376:Interleukin-2; D018664:Interleukin-12