Stabilisation of functional tumor necrosis factor-alpha by its soluble TNF receptors

Using two enzyme-linked immunosorbent assays (ELISA), one able to detect trimeric TNF-alpha, but not its monomeric form (T-ELISA), and the other able to detect trimeric plus monomeric TNF-alpha together (T+M-ELISA), the effect of two soluble TNF-alpha receptors (P55 and P75) on the dimethylsulphoxide (DMSO) induced conversion of TNF-alpha from a trimeric to a monomeric form was determined. When TNF-alpha was incubated in the presence of a 5% final concentration of DMSO, the level of trimer, as measured by the T-ELISA, dropped to between 25 and 50% of its initial concentration whereas no change in the level of TNF-alpha was observed with the T+M-ELISA. When the incubation was performed in the presence of P55 or P75, the reduction of trimeric TNF-alpha values in the presence of 5% DMSO decreased in proportion to the concentration of sTNF-R, whereas trimeric plus monomeric TNF-alpha values remained unaffected. These results suggest a shift of TNF-alpha from a trimeric to a monomeric form in the presence of DMSO, and that TNF-Rs play a major rôle in preventing this phenomena. This could have implications for therapeutic schedules.