Distinct effects of phorbol esters and exogenous diacylglycerols in the induction of murine thymocyte proliferation

✍ Scribed by Michael Stoeck; Rawleigh C. Howe; H. Robson MacDonald

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 532 KB
• Volume: 151
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041510103

✦ Synopsis

Murine thymocytes were stimulated with the protein kinase C activating agents Phorbol-I 2-myristate-13-acetate (PMA) or a more physiological membrane permeant diacylglycerol (dioctanoyl-sn-glycerol, DiC8) in the presence or absence of exogenous lymphokines (rlL-1 p, rlL-2). Whereas PMA directly induced reactivity to rlL-2, DiC8 did not but had to synergize with the calcium ionophore lonomycin. Expression of the p55 chain of the IL-2 receptor behaved similarly. In the absence of exogenous rlL-2, thymocytes proliferated in response to a combination of lonomycin and PMA; however, replacing PMA by a single addition of DiC8 did not result in proliferation. Stimulation with lonomycin plus repeated addition of DiC8 induced a low level of thyrnocyte proliferation and further addition of rlL-l p resulted in a significant increase. Purified immature (L3T4KLyt2-) thyrnocytes behaved similarly, but showed an increased sensitivity to rlL-1 p. Taken together, the data support the idea that PMA and the more physiological diacylglycerols do not possess totally equivalent activities in lymphocyte stimulation.