Engineering Antibodies Targeting p16 MHC-Peptide Complexes

Senescent cells undergo a permanent cell cycle arrest and drive a host of age-related pathologies. Recent transgenic mouse models indicate that removing cells expressing the senescence marker p16^Ink4a (p16) can increase median lifespan and delay the onset of many aging phenotypes. However, identifying and eliminating native human cells expressing p16 has remained a challenge. We hypothesize that senescent cells display peptides derived from p16 in major histocompatibility complex (MHC)-peptide complexes on the cell surface that could serve as targetable antigens for antibody-based biologics. Using Fab-phage display technology, we generated antibodies that bind to a p16 MHC-peptide complex from the human leukocyte antigen (HLA) allele HLA-B*35:01. When converted to single-chain Fab chimeric antigen receptor (CAR) constructs, these antibodies can recognize naturally presented p16 MHC-peptide complexes on the surface of cells and activate Jurkat cells. Furthermore, we developed antibodies against predicted p16 MHC-peptide complexes for HLA-A*02:01 that specifically recognize their respective antigen on the surface of cells. These tools establish a platform to survey the surface of senescent cells and provide a potential novel senolytic strategy.