Differential Production of Macrophage Inflammatory Protein 1γ (MIP-1γ), Lymphotactin, and MIP-2 by CD4+Th Subsets Polarized In Vitro and In Vivo

Abstract

Due to differential expression of chemokine receptors, the Th1 and Th2 subsets of CD4⁺T cells differ in their migratory responses to chemokines. These differences in the migration patterns are likely to play a role in the initiation and regulation of Th1 and Th2 immune responses, inflammatory processes, and T-cell-mediated pathology. In the present study we evaluated the role of activated Th cells as producers of chemokines. Three different sources of murine Th cells were used, i.e., long-term-cultured Th1 and Th2 cell clones, Th1 and Th2 cells differentiated from naïve CD4⁺spleen and lymph node cells in vitro, and Th1 and Th2 subsets polarized in vivo using a murine experimentalLeishmania majorinfection model. Following stimulation with anti-CD3, macrophage inflammatory protein 1γ (MIP-1γ) and lymphotactin were produced selectively by Th1 cells but not by Th2 cells. In contrast, only Th2 cells produced MIP-2. The possible biological relevance of these data was substantiated by the finding that in vivo-polarized Th1 cells, but not Th2 cells, produced MIP-1γ and lymphotactin while in vivo-polarized Th2 cells secreted MIP-2. The above data demonstrate that Th1 and Th2 cells differ in their ability to produce chemokines, suggesting that Th1 and Th2 subsets differentially contribute to recruitment of cells into inflammatory foci.