The purpose of the research has been to characterize the response of naïve or virus-specific swine T lymphocytes from different lymphoid compartments to Porcine Reproductive and Respiratory Syndrome Virus (PRRSV). Peripheral blood mononuclear cells (PBMCs), tracheobronchial lymph node (TLN) and lateral retropharyngeal lymph node (LLN) cells were labeled with PKH67 green fluorescence dye to measure cell proliferation and surface phenotypes were examined using anti-CD4, anti-CD8 or anti-CD25 monoclonal antibodies. Stimulation with Concanavalin A was also included as a positive control. Our results show that potential virus-specific T lymphocytes were found in the peripheral blood, although no cell proliferation was found in cultures of lymph node cells. We did find that the percentages of CD8+ T cells in cultures of lymph node cells from the virus-infected pig increased after in vitro stimulation with the Powell virus compared to the lymph node cells cultured in media only, suggesting that CD8+ T lymphocytes may play a role in the virus clearance and immune memory to PRRSV.