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-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.The agonistic antibody of CD28 is now under phase II clinical trials.
mRNA expression analysis:
Fig 1. RT-PCR analysis of the CD28 gene. The mCD28 mRNA was detected in both wild type C57BL/6 and heterozygous B-hCD28 mice, while the hCD28 mRNA was detected only in the heterozygous B-hCD28 mice.
Protein expression analysis:
Fig 2. Splenocytes from both wild type (WT) C57BL/6 and heterozygous B-hCD28 mice were analyzed by flow cytometry. Mouse CD28+ T cells were detected in both WT C57BL/6 and heterozygous B-hCD28 mice, while human CD28+ T cells were only detected in the heterozygous B-hCD28 mice.