Modulation of the transcripts for tumor necrosis factor-alpha and its receptors 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 TNF-R1) and TNF receptor type II (TNF-R 75 kDa or TNF-R2) in various tissues and white blood cells. While TNF mRNA rapidly accumulated in most tissues, TNF-R1 and TNF-R2 mRNA levels were found to be differentially regulated in lung, spleen, lymph nodes and white blood cells. In most cases, TNF-R mRNA levels did not parallel TNF mRNA levels. These observations indicate that TNF-R of both types of 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.