Rescue of thymocytes from cell death by vasoactive intestinal peptide.

Vasoactive intestinal peptide (VIP) has previously been shown to increase survival of cultured neurons and to prevent the neurotoxic effect of the envelope glycoprotein 120 of human immune deficiency virus (HIV). The present report shows that VIP also protects mouse and human thymocytes exposed to a cytolytic dose of prednisolone in vitro. The activity of VIP is dose-dependent, and specific, since the structurally related secretin has no effect. The effective concentration of VIP is within the physiological range, suggesting that VIP released from nerve terminals may modulate cell death in the thymic cortex. Results with an N-terminal and a C-terminal fragment of VIP implied that the complete VIP molecule is required for optimal protection against cytolysis.