Soluble forms of the TNF receptors, purified from human urine, inhibit TNF effects. Antibodies against the soluble receptors induce TNF-like effects: H. Engelmann1, D. Aderka1, H. Holtmann2, C. Brakebusch2, Y. Nophar1, D. Novick1, O. Kemper1, M. Rubinstein1, Y. Shemer Avni3, I. Sarov3 and D. Wallach1. The Weizmann Institute of Science, Rehovot, Israel1, The School of Medicine, Hannover, FRG2 and Ben-Gurion University Beer-Sheva, Israel3