The inhibitory activity is not due to a nonspecific cytotoxic activity, as indicated by the observations that 1) thymocyte viability was maintained even at high doses of IF and 2) IF did not inhibit the growth of the non-lymphocytic K562 human cell line. Moreover, the inhibitory activity displays some degree of tissue specificity in that it is present at considerably higher levels in testicular IF as compared with serum or the aqueous humor of the eye. flovent inhaler
While nothing can be concluded about the mechanism of action of the inhibitor from these data, the data do not eliminate the possibility that activated T cells at a certain phase of differentiation or proliferation are induced to undergo apoptosis by this activity. Evidence indicates that immune privilege in the rodent testis is due to an inability to recognize or initiate responses against antigens located in the testicular environment, a process that involves antigen presentation, T-cell activation, and proliferation (see review ). In the eye, privilege appears to involve the failure of lymphocytes to become cytolytically active. Consequently, the inhibitory activity in IF may be responsible for inactivating or deleting T cells as they pass through the testis.