Porcine γ/δ T lymphocyte subsets differing in their propensity to home to lymphoid tissue

Three types of T cell receptors (TcR) gamma/delta were identified in swine, all of which are disulfide-bonded cell surface heterodimers. The first, a 38/40-kDa molecule, is related to the TcR gamma/delta of sheep and cattle, and defines in swine a subset of CD4-CD8- T lymphocytes that is enriched in the circulating T lymphocyte pool. The other two receptors are private to swine. The second, a 37/40-kDa molecule, is expressed by the major subset of CD2-CD4-CD8- T lymphocytes that is neither enriched in nor excluded from lymphoid tissue. By contrast, the third type of TcR gamma/delta, a 40/46-kDa molecule, is found on CD2+CD4-CD8- T lymphocytes accumulating in lymphoid tissue. Thus, TcR gamma/delta T lymphocyte subsets differing in homing propensity are typified by the expression of distinct molecular forms of the TcR gamma/delta.