Differential expression of CD300a/c on human T(H)1 and T(H)17 cells

BACKGROUND: Human memory CD4(+ )T cells can be either CD300a/c(+ )or CD300a/c(- )and subsequent analyses showed that CD4(+ )effector memory T (T(EM)) cells are mostly CD300a/c(+), whereas CD4(+ )central memory T (T(CM)) cells have similar frequencies of CD300a/c(+ )and CD300a/c(- )cells. RESULTS: Extensive phenotypical and functional characterization showed that in both T(CM )and T(EM )cells, the CD300a/c(+ )subset contained a higher number of T(H)1 (IFN-γ producing) cells. Alternatively, T(H)17 (IL-17a producing) cells tend to be CD300a/c(-), especially in the T(EM )subset. Further characterization of the IL-17a(+ )cells showed that cells that produce only this cytokine are mostly CD300a/c(-), while cells that produce IL-17a in combination with other cytokines, especially IFN-γ, are mostly CD300a/c(+), indicating that the expression of this receptor is associated with cells that produce IFN-γ. Co-ligation of the TCR and CD300a/c in CD4(+ )T cells inhibited Ca(2+ )mobilization evoked by TCR ligation alone and modulated IFN-γ production on T(H)1 polarized cells. CONCLUSION: We conclude that the CD300a/c receptors are differentially expressed on human T(H)1 and T(H)17 cells and that their ligation is capable of modulating TCR mediated signals.