T-cells contain higher levels of TH mRNA than B-cells although protein levels appeared similar. On contrary, the PNMT mRNA and protein were higher in B-cells, which appeared to be the main source of PNMT in the spleen. T-cells increased TH and PNMT expression after acute stress while similar rise was observed in B-cells after repeated stress, most probably as a consequence of higher CA turnover in both cell populations. The rise in TH and PNMT was accompanied by an elevation of Bax/Bcl-2 mRNA ratio, number of apoptotic cells and also by a decline of IFN-¦Ã mRNA in both cell types. Reduction of IL-2 and IL-4 mRNA was also observed in B-cells.
Stress-induced stimulation of endogenous CA biosynthesis in lymphocytes is dependent on the type of lymphocyte population and duration of stressor and leads to attenuated IFN-¦Ã expression and induction of apoptosis. These changes might contribute to dysregulation of specific immune functions involving T- and B-cells and may decrease the ability to cope with intracellular agents following stress situations.