concanavalin-a and Respiratory-Syncytial-Virus-Infections

Innate and adaptive immune responses to respiratory syncytial virus (RSV) in neonates were assessed by cord blood mononuclear cell (MC) cytokine expression and proliferation and these responses were compared with those from adult peripheral blood MCs. In adult cells, inactivated and live virus invoked cytokines reflecting both innate and adaptive immunity (interleukin [IL]-6, interferon [IFN]-gamma, IL-2, tumor necrosis factor [TNF]-alpha, and IL-10). Low levels of IL-4 were detected, although only with inactivated virus. In contrast, in neonatal cells, inactivated virus invoked large levels of the innate immune cytokines IL-6, TNF-alpha, and IL-10 and reduced levels of IFN-gamma and IL-12 but no adaptive cytokines. Live virus induced fewer innate (IL-6, IL-10, and IFN-gamma) and no adaptive immune cytokines. RSV-induced proliferation was absent in neonatal MCs, although positive in adult MCs. Thus, exposure to RSV does not appear to occur before birth, and adaptive immune insufficiency or greater innate responses may account for early life RSV-induced illnesses.

Topics: Adult; Cell Division; Concanavalin A; Female; Fetal Blood; Humans; Immunity, Active; Immunity, Innate; Infant, Newborn; Interferon-gamma; Interleukin-10; Interleukin-2; Interleukin-4; Interleukin-6; Leukocytes, Mononuclear; Middle Aged; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Tumor Necrosis Factor-alpha; Virus Inactivation

In the present study peripheral blod mononuclear cells (MNC) obtained from normal uninfected lambs were used to study the possible effects of bovine respiratory syncytial virus (BRSV) on lymphocyte responses to the mitogens, phytohaemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) in vitro. Live BRSV had a depressive effect on the proliferative responses of normal MNC to PHA, Con A and PWM. Inactivated BRSV and a commercial preparation of prostaglandin E2 were also found to depress the proliferative responses of normal ovine MNC to PHA but recombinant tumour necrosis factor-alpha (TNF-alpha) had no such effect. Serum samples obtained from BRSV-infected lambs contained substances inhibitory to PHA-driven lymphocyte blastogenesis. Memory blastogenic responses to border disease virus (BDV) of lymyphocytes obtained from lambs previously primed with BDV were significantly reduced when lymphocytes were exposed to infectious BRSV.

Topics: Animals; Antigens, Viral; Border disease virus; Cattle; Cells, Cultured; Concanavalin A; Dinoprostone; Lymphocyte Activation; Lymphocytes; Mitogens; Phytohemagglutinins; Pokeweed Mitogens; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Bovine; Sheep; Tumor Necrosis Factor-alpha