Genetic variation in in-vitro cytokine-induced production of nitric oxide by murine peritoneal macrophages

Quantitative aspects of the in-vitro interferon (IFN)-gamma-induced nitric oxide (NO) production by peritoneal macrophages of eight inbred strains of mice were investigated. Animals employed in the study can be assorted into three phenotype categories: high, moderate, and low NO-responders. Concentr ation of nitrites in the 24-h supernatants of cells stimulated with recombi nant murine IFN-gamma (25 U/ml) reached the following values (mean a SERI; in mu M): C57BL/10 (33.7 +/- 1.88) = C57BL/6 (32.1 +/- 2.10) > SJL (24.0 +/ - 1.55) > CBA/J (18.1 +/- 7.79) = C3H/HeN (18.0 +/- 1.10) > DBA/2 (11.4 +/- 1.16) = DBA/1 (11.0 +/- 1.20) = Balb/c (11.0 +/- 1.16). Approximately 80% of the total variation was found to be controlled by genetic factors. No as sociation between the extent of NO formation and variation in the constitut ive expression of macrophage IFN-gamma receptor was observed. Similar magni tude of inter-strain differences was sustained after enhanced RIG-stimulati on of the cells with IFN-gamma + tumour necrosis factor (TNF)-alpha, but on ly high (strains BL/10, BL/6, SJL, CBA/J, C3H/HeN) and low (DBA/1, DBA/2, B alb/c) NO-responder phenotypes were detected after the triple cytokine cock tail composed of IFN-gamma + TNF-alpha + interleukin (IL)-10. The strain di fferences remained unchanged after the supplementation of culture medium wi th L-arginine or tetrahydrobipopterin. Genetically governed differences in IFN-gamma-induced NO production have been found to be tightly associated wi th differential expression of inducible nitric oxide synthase mRNA. Possibl e implications of the findings for various fields of NO biomedical research are discussed, Pharmacogenetics 10:493-501 (C) 2000 Lippincott Williams & Wilkins.