IFN-gamma production by Th1 cells generated from naive CD4(+) T cells exposed to norepinephrine

During activation in vivo, naive CD4(+) T cells are exposed to various endo genous ligands, such as cytokines and the neurotransmitter norepinephrine ( NE), To determine whether NE affects naive T cell differentiation, we used naive CD4(+) T cells sort-purified from either BALB/c or DO11.10 TCR-transg enic mouse spleens and activated these cells with either anti-CD3/anti-CD28 mAbs or APC and OVA(323-329) peptide, respectively, under Th1-promoting co nditions. RT-PCR and functional assays using selective adrenergic receptor (AR) subtype antagonists showed that naive CD4+ T cells expressed only the beta (2)AR subtype to bind NE and that stimulation of this receptor generat ed Th1 cells that produced 2- to 4-fold more IFN-gamma, This increase was d ue to more IFN-gamma produced per cell upon restimulation instead of more I FN-gamma -secreting cells, as determined by IFN-gamma -specific immunofluor escence and enzyme-linked immunospot, In contrast, Th1 cell differentiation was unaffected when naive T cells were exposed to NE and activated either in the presence of a neutralizing anti-IL-12 mAb or by APC from IL-12-defic ient mice. Moreover, the addition of IL-12 to the IL-la-deficient APC cultu res restored the ability of NE to increase Th1 differentiation. Taken toget her, these results indicate that a possible link may exist between the sign aling pathways used by NE and IL-12 to increase naive CD4+ T cell different iation to a Th1 cell.