Effects of recombinant human cytokines on mitogen-induced bovine peripheral blood mononuclear cell proliferation

Abstract

The effects of interleukin 1α (IL-1α), IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, and insulin growth factor-1 (IGF-1) on proliferation of mitogen-stimulated bovine peripheral blood mononuclear cells (PBMC) were determined. Four concentrations of each cytokine were incubated 48 or 96 h with PBMC alone or with PBMC and three concentrations of three different mitogens. The mitogens included concanavalin A (Con A), phytohemagglutinin (PHA), and Escherichia coli 055:B5 lipopolysaccharide (LPS). Proliferation of unstimulated PBMC was not affected by IL-1α, IL-1β, IL-3, IL-5, IL-6, IL-8, and IGF-1 whereas IL-2, IL-4, and IL-7 increased proliferation. Incubation of PBMC with Con A plus IL-1α, IL-2, IL-4, IL-7 or IL-8 increased proliferation when compared to PBMC that were incubated with either Con A or the cytokine alone. Interleukin-1β, IL-3, IL-5, IL-6 and IGF-1 did not influence proliferation of Con A-stimulated PBMC. Proliferation of PHA-stimulated PBMC was increased when PBMC were cultured with IL-2, IL-4 or IL-7, but not when cultured with IL-1α, IL-1β, IL-3, IL-5, IL-6, IL-8 or IGF-1. Similar results occurred with LPS-stimulated PBMC in that proliferation induced by LPS was enhanced by IL-2 or IL-7, but not by any of the other cytokines. These results suggest that in the presence or absence of certain mitogens, human IL-1α, IL-2, IL-4, IL-7, or IL-8 can enhance proliferation of bovine PBMC whereas IL-1β, IL-3, IL-5, IL-6 and IGF-1 do not.