Thy-1 cell surface antigen on cloned cell lines of the rat and mouse: stimulation by cAMP and by butyrate.

The level of the Thy-1 cell surface antigen on a number of established rat and mouse nerve cell lines can be stimulated by N6, O2'-dibutyryl adenosine 3':5'-cyclic monophosphoric acid (Bt2cAMP), in some cases up to the antigen level found in whole brain. On rat cell line BN1010-3, stimulation is also produced by phosphodiesterase inhibitors, adenosine 3':5'-cycle monophosphoric acid (cAMP) and its 8-bromo derivative, and L-isoproterenol. Hence, antigen elevation appears to occur via cAMP-related metabolism. It is not a consequence of morphological changes brought about by cAMP elevation in these cells, and is apparently independent of the inhibition of cell division by the nucleotide. Elevations of intracellular cAMP levels for at least one hour are needed to produce Thy-1 stimulation, after which an enhanced level of Thy-1 is observable after about 12 h. Continuous stimulation is required to maintain elevated antigen levels, for upon removal of the stimulating agent, the level of Thy-1 returns to the original unstimulated value within 48 h. Potent stimulation of the antigen level is also obtained with butyrate at 1--2 mM, which appears to be acting by a cAMP independent mechanism.