Cd80 Knockout mouse models

Cd80 encodes B7-1, the mouse ortholog of human CD80, a type I membrane glycoprotein with IgV and IgC domains expressed on activated dendritic cells, macrophages, and B cells that delivers costimulation by binding CD28 and is captured with higher affinity and slower off-rate by CTLA4. CD80 dimerizes at the cell surface, which favors CTLA4 bivalent engagement and transendocytic ligand removal, and it additionally forms a cis heterodimer with PD-L1 that sterically blocks PD-1 binding while preserving CD28 engagement, an interaction that reframes how checkpoint blockade shifts costimulatory balance. Nulls have mild phenotypes because Cd86 covers most priming functions with faster kinetics and broader constitutive expression, so Cd80 Cd86 double deficiency is generally required to abolish CD28 costimulation. Reach for conditional alleles with dendritic cell or B cell Cre when the presenting compartment is the question, and humanization when abatacept or belatacept binding and CD80 PD-L1 cis biology are the readout.

Whole body loss of Cd80 gives the clearest readout when the question is whether the gene is required at all. Follow up tissue work can still move to a conditional allele if lethality or compensation appears.