Figure 1.

Chemically self-assembled nanorings as prosthetic antigen receptors. Bivalent DHFR² protein monomers spontaneously form nanorings upon the addition of a dimeric form of methotrexate (bis-MTX). These monomers can be fused to a single αCD3 or αB7-H3 scFv, forming targeted DHFR² monomers. A, Mixing αCD3 and αB7-H3 DHFR² monomers together at a 1:1 ratio with bis-MTX forms a stochastic mixture of multivalent bispecific CSANs that can interact with both T cells and B7-H3⁺ target cells. B, In this work, to assess the efficacy of the bispecific CSANs, different monospecific CSANs were used as controls where only one targeted monomer—either αCD3 or αB7-H3—was mixed 1:1 with a “non-targeted” DHFR² monomer to oligomerize into monospecific CSANs upon addition of bis-MTX.