Rapid expansion and IL-4 expression by Leishmania-specific naive helper T cells in vivo

Immunity. 2002 Aug;17(2):191-200. doi: 10.1016/s1074-7613(02)00363-1.

Abstract

CD4 T cells are pivotal for effective immunity, yet their initial differentiation into effector subsets after infection remains poorly defined. We examined CD4 T cells specific for the immunodominant Leishmania major LACK antigen using MHC/peptide tetramers and IL-4 reporter mice. Comprising approximately 15 cells/lymph node in naive mice, LACK-specific T cells expanded over 100-fold, and 70% acquired IL-4 expression by 96 hr. Despite their pathogenic role in susceptible mice, LACK-specific precursor frequency, expansion, and IL-4 expression were comparable between susceptible and resistant mice. When injected with unrelated antigen, Leishmania efficiently activated IL-4 expression from naive antigen-specific T cells. CD4 subset polarization in this highly characterized model occurs independently from IL-4 expression by naive T cells, which is activated indiscriminately after parasitism.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, Protozoan / immunology*
  • CD4-Positive T-Lymphocytes / immunology
  • Female
  • Gene Expression
  • Hematopoietic Stem Cells / immunology
  • Histocompatibility Antigens Class II / immunology
  • Immunodominant Epitopes / immunology
  • Immunophenotyping
  • Interleukin-4 / genetics*
  • Leishmania major / immunology*
  • Leishmaniasis, Cutaneous / immunology*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Protozoan Proteins / immunology*
  • T-Lymphocytes, Helper-Inducer / cytology
  • T-Lymphocytes, Helper-Inducer / immunology*
  • Time Factors

Substances

  • Antigens, Protozoan
  • Histocompatibility Antigens Class II
  • I-Ad antigen
  • Immunodominant Epitopes
  • Protozoan Proteins
  • LACK antigen, Leishmania
  • Interleukin-4