Relative abilities of 4-1BB (CD137) and CD28 to co-stimulate the response of cytokine deflected Th1 and Th2 cells

In this report we show that allo-stimulated naive CD4(+) cells when culture d in IL-2, IFN-gamma, IL-12 and anti-IL-l differentiated into Th1 cells exp ressing very low amounts of 4-1BB molecule, but high amounts of CD28. By co ntrast, allo-stimulated naive CD4(+) cells cultured in the presence of exog enous IL-2, IL-10, IL-4 and anti-INF-gamma evolved into Th2 expressing high amounts of both 4-1BB and CD28. Various Th1/Th2 clones derived from limiti ng dilution also exhibited similar expression pattern. This differential ex pression of co-stimulatory molecules on Th subsets account for the ability of 4-1BB to trigger both the proliferation and production of IL-4 by Th2 ce lls only and for the ability of CD28 to trigger proliferation and typical s ecretion in both Th1 and Th2 cells.