Involved in the costimulatory signal essential for T-lymphocyte activation. T-cell proliferation and cytokine production is induced by the binding of CD28, binding to CTLA-4 has opposite effects and inhibits T-cell activation.
(Microbial infection) Acts as a receptor for adenovirus subgroup B.
Subcellular locations: Membrane
Expressed on activated B-cells, macrophages and dendritic cells.