MODULATION OF THE TRANSCRIPTS FOR TUMOR-NECROSIS-FACTOR-ALPHA AND ITSRECEPTORS IN-VIVO

We investigated the effects of a single bacterial lipopolysaccharide ( LPS) injection in vivo on the gene expression of tumor necrosis factor -alpha (TNF) and its receptors: TNF receptor type I (TNF-R 55 kDa or T NF-R1) and TNF receptor type II (TNF-R 75 kDa or TNF-R2) in various ti ssues and white blood cells. While TNF mRNA rapidly accumulated in mos t tissues,TNF-R1 and TNF-R2 mRNA levels were found to be differentiall y regulated in lung, spleen, lymph nodes and white blood cells. In mos t cases, TNF-R mRNA levels did not parallel TNF mRNA levels. These obs ervations indicate that TNF-R of both types are capable of modulating the host response to LPS, not only by shedding of their extracellular domains, but also by strict regulation of their gene expression.