Corynebacterium parvum (Propionibacterium acnes): An inducer of tumor necrosis factor-α in human peripheral blood mononuclear cells and monocytesin vitro

Abstract

The present study investigates the potential capacity of the immunostimulant Corynebacterium parvum (C.p.) to induce tumor necrosis factor‐α (TNF‐α) in human peripheral blood mononuclear cells (PBMC) and blood monocytes (BMo) in vitro. Both at the mRNA and protein level, stimulation of PBMC and BMo upon C.p. induces TNF‐α. Compared to the hitherto used TNF‐α inducers in vitro such as Sendai virus, phytohemagglutinin or lipopolysaccharide the C.p. stimulus displayed a threefold stronger induction of TNF‐α production (p < 0.001). Using C.p. as an inducer it was possible to demonstrate that TNF‐α production is regulated by prostaglandin E₂; preincubation of the cells with prostaglandin E₂ resulted in a reduced C.p.‐mediated TNF‐α production (p < 0.001). Coincubation of interferon‐γ (IFN‐γ) together with C.p. led to an enhanced release of TNF‐α, supporting the assumption that C.p. is a potent TNF‐α inducer. The additive effect of IFN‐γ and TNF‐α on the receptor level was demonstrated by addition of IFN‐γ antibodies to the PBMC cultures. Under these conditions TNF‐α production, stimulated by C.p. and IFN‐γ, was decreased by 30%, compared to the production in assays supplemented with C.p. alone. From these data we conclude that C.p. is a new inducer of TNF‐α in vitro and a useful tool to study TNF‐α production of PBMC and BMo from either healthy donors or from patients.