Independent regulation of 55-kDa and 75-kDa tumor necrosis factor receptors during activation of human peripheral blood B lymphocytes
✍ Scribed by Bjørn K. Erikstein; Erlend B. Smeland; Heidi Kiil Blomhoff; Steinar Funderud; Kristian Prydz; Werner Lesslauer; Terje Espevik
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 498 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0014-2980
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✦ Synopsis
We have studied the expression of two different tumor necrosis factor receptors (TNFR; 55 kDa and 75 kDa) on resting and activated human peripheral blood B lymphocytes using specific monoclonal antibodies (mAb). Flow cytometric analysis revealed that most resting B cells expressed small amounts of the 75-kDa TNFR, and that the 75-kDaTNFR was markedly up-regulated upon stimulation with anti-y or Staphylococcus aureus Cowan strain I (SAC). In contrast, the expression of the 55-kDaTNFR was low on resting as well as on activated cells. B cell activation was accompanied by an increased binding of biotinylated TNF-a, and this binding could be blocked by preincubation by utr-1 (anti-75-kDaTNRF), but not the htr (anti-55-kDa TNFR) antibodies. Notably, a number of cytokines tested (interleukin 1 to 8, interferon-y, TNF-a and -p) did not influence the expression of either the 75-kDa or the 55-kDa TNFR when given to resting B cells. Moreover, phorbol 12-myristate 13-acetate led to an early, marked down-regulation of the 75-kDa TNFR expression, followed by a later modest increase after > 24 h. In contrast to other cell systems where htr mAb have been found either to mimic or to inhibit TNFaction, htr mAb had insignificant effects in assays for restimulation of preactivated B cells. However, utr-1 markedly inhibited the TNF-@ but only partly inhibited the TNF-a-induced proliferation. Taken together, our data suggest that changes in 75-kDa protein expression is responsible for the increased TNFR expression on activated vs. resting peripheral blood B cells and that this protein also may play an important functional role.