MHC class II restricted innate-like double negative T cells contribute to optimal primary and secondary immunity to Leishmania major

PLoS Pathog. 2014 Sep 18;10(9):e1004396. doi: 10.1371/journal.ppat.1004396. eCollection 2014 Sep.

Abstract

Although it is generally believed that CD4(+) T cells play important roles in anti-Leishmania immunity, some studies suggest that they may be dispensable, and that MHC II-restricted CD3(+)CD4(-)CD8(-) (double negative, DN) T cells may be more important in regulating primary anti-Leishmania immunity. In addition, while there are reports of increased numbers of DN T cells in Leishmania-infected patients, dogs and mice, concrete evidence implicating these cells in secondary anti-Leishmania immunity has not yet been documented. Here, we report that DN T cells extensively proliferate and produce effector cytokines (IFN-γ, TNF and IL-17) and granzyme B (GrzB) in the draining lymph nodes and spleens of mice following primary and secondary L. major infections. DN T cells from healed mice display functional characteristics of protective anti-Leishmania memory-like cells: rapid and extensive proliferation and effector cytokines production following L. major challenge in vitro and in vivo. DN T cells express predominantly (> 95%) alpha-beta T cell receptor (αβ TCR), are Leishmania-specific, restricted mostly by MHC class II molecules and display transcriptional profile of innate-like genes. Using in vivo depletion and adoptive transfer studies, we show that DN T cells contribute to optimal primary and secondary anti-Leishmania immunity in mice. These results directly identify DN T cells as important players in effective and protective primary and secondary anti-L. major immunity in experimental cutaneous leishmaniasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adoptive Transfer
  • Animals
  • Blotting, Western
  • Cells, Cultured
  • Cytokines / genetics
  • Cytokines / metabolism
  • Female
  • Histocompatibility Antigens Class II / immunology*
  • Immunity, Innate / immunology*
  • Immunoenzyme Techniques
  • Leishmania major / immunology*
  • Leishmaniasis, Cutaneous / immunology*
  • Leishmaniasis, Cutaneous / parasitology
  • Mice
  • Mice, Inbred C57BL
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Receptors, Antigen, T-Cell, alpha-beta / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • T-Lymphocyte Subsets / immunology*

Substances

  • Cytokines
  • Histocompatibility Antigens Class II
  • RNA, Messenger
  • Receptors, Antigen, T-Cell, alpha-beta