Tumour necrosis factor enhances the asbestos-induced production of reactive oxygen metabolites by human polymorphonuclear leucocytes (PMN)

Abstract

SUMMARYWe studied the effect of recombinant lumour necrosis factor-alpha (TNF-x) on the produclion of reactive oxygen metabolites (ROM) by human PMN exposed in vitro to chrysotile and crocidolite asbestos fibres, quartz dusts and opsonized i^ymosan. TNF caused a significani increase in ROM release by PMN, and signilicanlly and dosc-dependentiy amplitied ihc ROM produclion induced by asbestos fibres. The amphficaiion of ROM produclion by TNF can be of crucial importance in Ihe process of lung inflammation und librogenesis in pncumoconioscs.

Bacillus Calmette-Guérin (BCG) and immunoglobulins synergistically enhance mineral dust-induced production of reactive oxygen metabolites by human monocytes

“…IgD. light chains, and secretory IgA inhibit the ceil responses [10]. Our present results show that BCG further increases the stimulating effect of immunoglobulins.…”

“…TNF-Q has been suggested to be a critical mediator in the pathogenesis of pulmonary fibrosis, and our earlier results have shown an enhancing effect of TNF-a on mineral dust-induced ROM production by human neutrophils [15]. Interestingly, the enhancing efTect of TNF-o on human monocyte ROM generation was weak, and did not even reach statistica!…”

“…[26], the level of IgG, IgA, and IgM correlated with the severity of the clinical findings. IgG and IgA act synergistically with various mineral fibres in the generation of ROM by human neutrophils and macrophages [10,14]. Certain eytokines, such as IFN-7, activate human macrophages, and a subsequent exposure to immunoglobulin and asbestos fibres amplifies ROM production as much as 20-fold [14].…”

“…It is increased by the presence of polyclonal immunoglobulin and several monoclonal immunoglobulins [10][11][12], and in vitro activation of human macrophages with BCG and interferon-gamma (IFN-7) before an exposure of the cells to mineral dusts also has an enhancing effect on ROM generation [13,14]. Tumour necrosis factor-alpha (TNF-Q) also amplifies mineral dust-induced ROM production by human neutrophils [15] The aim of the present work was to evaluate whether the combination of host response mediators (immunoglobulins, TNF) and exogenic factors (BCG) have a synergistic enhancCorrespondence: Peter Nyberg, Mjolbolsta Hospital, SF-10350 Mjolbolsta, Finland.…”