Expression and release of IL-2 receptor and production of IL-2 by activated T lymphocyte subsets.

T lymphocyte subsets differ in expression of cell surface antigen and functional properties. Both CD4+ and CD8+ subsets express interleukin-2 receptor (IL-2R) following their activation in vitro. In the present investigation T lymphocyte subsets were activated by different mitogens and IL-2R expression was enumerated on these stimulated subsets. Peripheral blood mononucleated cells (PBMC) were stimulated with phytohaemagglutinin (PHA) and pokeweed mitogen (PWM) and then stained with anti-CD4 or anti-CD8 antibodies conjugated with fluorescein isothiocyanate and anti-IL-2R monoclonal antibody conjugated with phycoerythrin using a direct immunofluorescence technique. The percentage of IL-2R positive lymphocytes was enumerated by flow cytometry. The results showed that mitogen activated lymphocytes expressed variable degrees of IL-2R which were significantly higher than the control. 53% of CD4+ lymphocytes and 28% of CD8+ expressed IL-2R following PHA stimulation in vitro. Similarly, 47% of CD4+ lymphocytes and 23% of CD8+ lymphocytes expressed IL-2R following PWM stimulation. The present study also revealed that the release of soluble IL-2R (sIL-2R) and IL-2 production in supernatant from cultured PBMC varied with different mitogen stimulation. Using the same concentration of PHA and PWM as used to study IL-2R expression, higher activity of sIL-2R was detected in PHA stimulated lymphocytes as compared to PWM treated lymphocytes. However, IL-2 production was more in culture medium from PMW treated PBMC. Thus, there was a significant correlation between the cellular and soluble IL-2R but the production of IL-2 from activated PBMC cells had no good correlation with either the cellular IL-2R expression or the release of sIL-2R.(ABSTRACT TRUNCATED AT 250 WORDS)