The protein encoded by this gene is essential for T-cell proliferation and survival, cytokine production, and T-helper type-2 development. Several alternatively spliced transcript variants encoding different isoforms have been found for this gene.CD28 (CD28 Molecule) is a Protein Coding gene. Diseases associated with CD28 include Mycosis Fungoides and Sezary's Disease. Among its related pathways are ICos-ICosL Pathway in T-Helper Cell and CTLA4 Signaling. GO annotations related to this gene include identical protein binding and SH3/SH2 adaptor activity. An important paralog of this gene is CTLA4.