Design of the hCD3ε/hCD28 mouse
The double-humanized CD3ε/CD28 model was generated from intercrossing hCD3ε and hCD28 mice.
The CD3ε humanized model was developed to express the human epitope of the CD3ε chain, which is recognized by T-cell engagers (clone SP34). The rest of the extracellular domain is murine to preserve the amino acids involved in the interaction with CD3γ and CD3δ. Similarly, the transmembrane domains and the intracellular domains are murine to enable salt bridge interaction, interaction with the CD3ζ, and the signaling into mouse cells.
The humanized CD28 model, developed by Knockin at the mouse CD28 locus, expresses a chimeric CD28 with a human extracellular and murine transmembrane and intracellular domains. hCD28 expression displays a physiological regulation and expression pattern. This double-humanized model enables assessment of both compounds targeting human CD3ε and/or human CD28 in immunocompetent mice.