title: Suppressed peripheral blood lymphocyte blastogenesis in pre- and postpartal sheep by chronic heat-stress, and suppressive property of heat-stressed sheep serum on lymphocytes.
abstract: Phytohemagglutinin (PHA) and concanavalin A (Con A)-induced blastogenesis of peripheral blood lymphocytes was examined in heat-stressed pre- and postpartal sheep. The peak responses of lymphocytes to PHA and Con A in heat-stressed sheep revealed significant reduction before and after parturition compared with those in the corresponding control animals kept under thermoneutral conditions. Furthermore, the effect of serum from control or heat-stressed sheep on PHA-induced lymphocyte blastogenesis was examined. Supplementation of serum from heat-stressed sheep significantly suppressed the blastogenesis of lymphocytes obtained from healthy sheep, bovine, and human donors. Unlike dexamethasone, heat-stressed sheep serum did not inhibit IL-2 production by PHA-stimulated human peripheral blood lymphocytes. These results indicate that the immunosuppression of heat-stressed sheep is in part mediated by serum factor(s) that can modulate T-cell function in a species nonspecific manner.
authors.affiliation: University of Missouri-Columbia, Dairy Science Department 65211.
authors.forename: Y
authors.initials: Y
authors.lastname: Niwano
authors.forename: B A
authors.initials: BA
authors.lastname: Becker
authors.forename: R
authors.initials: R
authors.lastname: Mitra
authors.forename: C W
authors.initials: CW
authors.lastname: Caldwell
authors.forename: E B
authors.initials: EB
authors.lastname: Abdalla
authors.forename: H D
authors.initials: HD
authors.lastname: Johnson
mesh_terms: D000818:Animals; D003208:Concanavalin A / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D010835:Phytohemagglutinins / Q000494:pharmacology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000276:immunology*; D011644:Puerperal Disorders / Q000097:blood / Q000276:immunology*; D012756:Sheep / Q000097:blood / Q000276:immunology; D013045:Species Specificity; D013312:Stress, Physiological / Q000097:blood / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
chemical_list: D007376:Interleukin-2; D010835:Phytohemagglutinins; D003208:Concanavalin A; D003907:Dexamethasone