Abstract FR:

The p388d1 murine macrophage cell line has been chosen to study events resulting from the transduction of immunomodulatory signals. Owing to the frequent implication of the c-myc gene in the tumorigenicity of hematopoietic cells, the normal c-myc status in this cell line is demonstrated by southern analysis. The early modulation of the c-fos and c-myc proto-oncogene expression has been studied by northern analysis and the dna synthesis by #3h-thymidine incorporation after treatment of p388d1 cells by tpa, calcium ionophore a23187, mdp and csf-1. No correlation could be evidenced in this cell line between the mitogenic effect and the c-fos and c-myc modulation induced by these immunomodifiers. The impact of lps, tpa and dibutyryl-cyclic amp on mhc class ii antigen (ia) has been revealed by radio-immuno-assay. These compounds inhibited constitutive or induced by interferon-gamma ia expression. This inhibition seemed to be in relation with c-fos expression. The ia expression was therefore analysed either after c-fos translation blockage by a dna antisense either after overexpression of c-fos by transfection of p388d1 cells with a plasmid containing the c-fos gene. The first results seemed to confirm an inverse correlation between the c-fos induction and the inhibition of ia expression