Open AccessAbdominal surgery reduces the ability of rat spleen cells to synthesize and secrete active tumour necrosis factor‐alpha (TNF‐α) by a multilevel regulation
Author(s) -
Nitza Lahat,
Michal A. Rahat,
Vera Brod,
Sara Cohen,
Gabriel Weber,
Amalia Kinarty,
Haim Bitterman
Publication year - 1999
Publication title -
clinical & experimental immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 135
eISSN - 1365-2249
pISSN - 0009-9104
DOI - 10.1046/j.1365-2249.1999.00758.x
Subject(s) - tumor necrosis factor alpha , splenocyte , spleen , western blot , lipopolysaccharide , biology , secretion , microbiology and biotechnology , cytokine , northern blot , messenger rna , immune system , alpha (finance) , immunology , endocrinology , medicine , biochemistry , gene , construct validity , nursing , patient satisfaction
We have previously shown that abdominal surgery (explorative laparotomy) reduces the ability of lipopolysaccharide (LPS)‐triggered spleen macrophages to secrete TNF‐α. In this study we characterize possible mechanisms which could be responsible for the reduction in splenic production of TNF‐α. Post‐operative and control (unoperated) rat splenocytes or enriched splenic macrophages were cultured with LPS. Steady‐state levels of TNF‐α mRNA were determined by Northern and slot blot analyses, and validated by quantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR). The amount of TNF‐α protein was measured by Western blot analysis, and its biological activity was determined by the fibroblast L‐929 cytotoxicity assay. Surgery induced a 12‐fold inhibition in TNF‐α activity ( P < 0.02), caused up to two‐fold reduction in the accumulation of TNF‐α mRNA ( P < 0.01), and suppressed TNF‐α protein maturation into its 17‐kD form in cellular extracts. Post‐surgical spleen supernatants revealed mainly a band of a lower molecular weight (14 kD). Our data suggest a multilevel regulation of post‐operative inhibition of TNF‐α response to LPS, at the accumulation of mRNA, translational and secretory levels. We also suggest that the reduced bioactivity could be partially caused by a proteolytic cleavage of TNF‐α. Since TNF‐α is an important participant in immune responses, its reduced production and activity may be a central mechanism of post‐operative immunosuppression.