Ctla4 Conditional Knockout mouse models

Ctla4, ortholog of human CTLA4, encodes CD152, an inhibitory CD28 family homodimer that shares the MYPPPY ligand motif but binds CD80 and CD86 with far higher avidity, outcompeting CD28 and physically stripping ligands from antigen presenting cells by transendocytosis, a cell-extrinsic mechanism central to regulatory T cell suppression. Surface residence is brief because the cytoplasmic YVKM motif recruits AP-2 for constitutive clathrin-mediated internalization and LRBA-dependent recycling, and the same motif engages PP2A and SHP-2. Germline deletion is catastrophic, with fatal lymphoproliferation, myocarditis, and pancreatitis by three to four weeks, so adult studies demand conditional flox alleles with Foxp3-Cre or Cd4-CreER to separate regulatory from conventional T cell requirements. No paralog compensates, since CD28 is the functional antagonist rather than a substitute. Humanized CTLA4 knockins are essential for ipilimumab and Fc-engineered antibody work, and haploinsufficient alleles suit human CTLA4 insufficiency and LRBA deficiency biology.

Conditional deletion of Ctla4 limits the genetic change to the lineage you choose. That helps in oncology, immunology, and metabolic work where systemic loss would muddy the read. After you confirm Cre specificity, crossing to Ctla4 floxed stock yields usable cohorts.