Enables identical protein binding activity. Acts upstream of or within several processes, including cytotoxic T cell differentiation; defense response to virus; and positive regulation of calcium-mediated signaling. Located in external side of plasma membrane. Is expressed in several structures, including endocrine gland; exocrine gland; genitourinary system; gut; and hemolymphoid system gland. Orthologous to human CD8A (CD8a molecule). [provided by Alliance of Genome Resources, Apr 2022]