<prompt> Which of the following is a pan T lymphocite marker -CD2CD3CD 19CD 25  <response>: The TCR is a disulfide-linked membrane-anchored heterodimeric protein normally consisting of the highly variable alpha a and beta b chains expressed as pa of a complex with the invariant CD3 chain molecules. Reff: Ananthanarayanan Panikers textbook of microbiology 9th edition pg: 133 