title: Dual effect of vasoactive intestinal peptide on the mitogenic response of rabbit spleen lymphocytes.
abstract: The effects of vasoactive intestinal peptide (VIP) have been investigated on the mitogenic response of rabbit spleen cells. Specific binding of 125I-VIP to these mononuclear cells is rapid and saturable. Analysis of binding reveals two classes of binding sites, a class of high-affinity binding sites with KD = 0.93 +/- 0.11 nM and maximal binding capacity of 2000 +/- 560 sites/cell, and a class of low-affinity binding sites with KD = 225 +/- 58 nM and maximal binding capacity of 280,000 +/- 60,000 sites/cell. The VIP regulatory effect on mitogen-stimulated rabbit spleen cell proliferation appears to be time dependent and bimodal. When VIP was added simultaneously with mitogens, it induced an inhibition of the proliferative response. With concanavalin A (Con A) or pokeweed mitogen (PWM), addition of 10(-8) M VIP resulted in a maximal 30% inhibition of [3H]thymidine incorporation after 96 h of culture. This inhibitory effect was significant at concentrations from 10(-8)-10(-6) M and half-maximal inhibition was obtained with 1.2 x 10(-9) M VIP. By contrast, when rabbit spleen cells were preincubated for 18 h with VIP alone, the lymphocyte proliferative response to Con A was increased. However, this increase was mitogen-selective, since it was only observed when the T-cell mitogen Con A was used. The maximal response was obtained after 96 h of culture in the presence of Con A. The VIP stimulatory effect was dose-dependent with a maximal effect at 10(-7) M and a half-maximal effect at 1.7 x 10(-9) M VIP. The effect of VIP was also time-dependent, since a 6 h preincubation was sufficient to induce a significant increase in the proliferative response which was maximal after an 18 h preincubation.
authors.affiliation: INRA, Toulouse, France.
authors.forename: S
authors.initials: S
authors.lastname: Peuriere
authors.forename: C
authors.initials: C
authors.lastname: Susini
authors.forename: J P
authors.initials: JP
authors.lastname: Esteve
authors.forename: N
authors.initials: N
authors.lastname: Vaysse
authors.forename: L
authors.initials: L
authors.lastname: Escoula
mesh_terms: D000818:Animals; D003208:Concanavalin A / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D008934:Mitogens / Q000494:pharmacology*; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011817:Rabbits; D011964:Receptors, Gastrointestinal Hormone / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide; D013154:Spleen / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013535:Suspensions; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D008934:Mitogens; D011043:Pokeweed Mitogens; D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D013535:Suspensions; D003208:Concanavalin A; D014660:Vasoactive Intestinal Peptide