A biomimetic five-module chimeric antigen receptor (^5MCAR) designed to target and eliminate antigen-specific T cells.

Abstract

T cells express clonotypic T cell receptors (TCRs) that recognize peptide antigens in the context of class I or II MHC molecules (pMHCI/II). These receptor modules associate with three signaling modules (CD3γε, δε, and ζζ) and work in concert with a coreceptor module (either CD8 or CD4) to drive T cell activation in response to pMHCI/II. Here, we describe a first-generation biomimetic five-module chimeric antigen receptor (^5MCAR). We show that 1) chimeric receptor modules built with the ectodomains of pMHCII assemble with CD3 signaling modules into complexes that redirect cytotoxic T lymphocyte (CTL) specificity and function in response to the clonotypic TCRs of pMHCII-specific CD4⁺ T cells, and 2) surrogate coreceptor modules enhance the function of these complexes. Furthermore, we demonstrate that adoptively transferred ^5MCAR-CTLs can mitigate type I diabetes by targeting autoimmune CD4⁺ T cells in NOD mice. This work provides a framework for the construction of biomimetic ^5MCARs that can be used as tools to study the impact of particular antigen-specific T cells in immune responses, and may hold potential for ameliorating diseases mediated by pathogenic T cells.