CD28 (Cluster of Differentiation 28) is one of the proteins expressed on T cells that provide co-stimulatory signals required for T cell activation and survival. T cell stimulation through CD28 in addition to the T-cell receptor (TCR) can provide a potent signal for the production of various interleukins (IL-2 and IL-6 in particular). CD28 is the only B7 receptor constitutively expressed on naïve T cells. Association of the TCR of a naive T cell with MHC: antigen complex without CD28: B7 interaction results in a T cell that is anergic. Agonistic antibodies targeting CD28 have entered clinical trials.
Splenocytes from both wild type (WT) C57BL/6 and homozygous B-hCD28 mice were analyzed by flow cytometry.
Mouse CD28+ T cells were detectable in both WT C57BL/6 and homozygous B-hCD28 mice, while human CD28+ T cells were only detectable in the homozygous B-hCD28 mice. This observation could be attributed to the possibility that the anti-mouse CD28 antibody may cross-react with human CD28.
B-hCD28 model evalution
C57BL/6 and B-hCD28 mice were immuned by hPD-L1 recombination protein with CFA. No significant difference was detected, indicating that the B7-1/CD28 co-stimulating signaling pathway was normal in hCD28 mice. Chimera of CD28 had efficient activity.
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