Abstract
Infection of BALB/c mice with Leishmania major results in the rapid accumulation of IL-4 transcripts within CD4+ T cells that react to the parasite Leishmania homologue of mammalian RACK1 (LACK) Ag. Because memory/effector cells secrete IL-4 more rapidly than naive cells, we sought to analyze the phenotype of these lymphocytes before infection. Indeed, a fraction of LACK-specific CD4+ T cells expressed a typical CD62 ligand(low)CD44(high)CD45RB(low) phenotype in uninfected mice. LACK-specific T cells were primed in gut-associated lymphoid tissues by cross-reactive microbial Ags as demonstrated by their reactivity with bacterial extracts and by the ability of APCs from the mesenteric LN of BALB/c mice to induce their proliferation. Also, mice in which the digestive tract has been decontaminated exhibited a reduced proportion of LACK-specific T cells expressing a memory/effector phenotype and did not exhibit the early accumulation of IL-4 transcripts induced by L. major. Thus, LACK-specific T cells represent a subset of CD4+ T cells which have acquired the ability to rapidly secrete IL-4 as the result of their priming by cross-reactive microbial Ags. Tracking the fate of these cells may provide information about the regulation of cell-mediated immune responses to gut Ags in physiological and pathological situations.
Original language | English (US) |
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Pages (from-to) | 5637-5645 |
Number of pages | 9 |
Journal | Journal of Immunology |
Volume | 165 |
Issue number | 10 |
State | Published - Nov 15 2000 |
Externally published | Yes |
ASJC Scopus subject areas
- Immunology