Similarities in cAMP Responses Between Murine Lymphoid Cell Lines and Subsets of Mouse Lymphocytes

Intracellular cAMP responses to forskolin (which stimulates independently of hormone receptors) and to several hormones were studied in mouse lymphoid cell lines of B- and T-cell origin and in subpopulations of mouse lymphocytes. In the T-cell lines, isoproterenol caused an increase in cAMP amounting at most to 28% of that caused by 100 microM forskolin. In contrast, in the B-cell lines the increase ranged from 50% to over 100%. In 11 of 13 T-cell lines, forskolin at 1 microM concentration potentiated the isoproterenol response five- to tenfold. Forskolin potentiation was also found in thymocytes and peripheral T-cells but not in B-cell lines. The relative increases in intracellular cAMP evoked by isoproterenol, prostaglandin E2 (PGE2) and histamine varied markedly from cell line to cell line. For instance, three lines carrying the T-helper cell marker L3T4 responded only to PGE2 and not to isoproterenol, whereas two cell lines carrying the Ly2 marker gave a higher response to isoproterenol than to PGE2. The results indicate that subsets of lymphocytes respond differently to various hormones and that these differences are maintained in continuous cell lines.