The present invention provides a polypeptide comprising the isolated amino acid sequence of a pre-ligand assembly domain (PLAD) of a TNF-like receptor. Also provided by this invention is a polypeptide comprising the isolated amino acid sequence of a pre-ligand assembly domain (PLAD), wherein the PLAD is selected from the group consisting of: the PLAD of a TNF-R, the PLAD of p60, the PLAD of p80, the PLAD of Fas (CD95/APO-1), the PLAD of TRAIL receptors, the PLAD of LTβR, the PLAD of CD40, the PLAD of CD30, the PLAD of CD27, the PLAD of HVEM, the PLAD of OX40 and the PLAD of DR4. TNF-R, p60, p80, Fas, TRAIL receptor, LTβR, CD40, CD30, CD27, HVEM, OX40, DR4, TROY, EDAR, XEDAR, DCR3, AITR, 4-1BB, DR3, RANK, TACI, BCMA, DR6, DPG, DR5, DCR1 AND DCR2 are all members of the TNF receptor superfamily or the TNF-like receptor family. The invention also provides the PLAD for other members of the TNF receptor superfamily. The polypeptides of the present invention can be utilized to inhibit oligomerization of members of the TNF receptor superfamily. These polypeptides can also be utilized to inhibit ligand binding to members of the TNF receptor superfamily. The present invention also provides a composition comprising an inhibitor of TNF receptor oligomerization. Further provided by this invention are members of the TNF receptor superfamily that are lacking a PLAD.