The rapid generation of genetic variation in porcine reproductive and respiratory syndrome virus (PRRSV) makes it difficult to characterize the porcine T-cell response to this virus. We evaluated the dynamic fluctuations of porcine T-cell responses in peripheral blood mononuclear cells (PBMCs) infected with North American PRRSV (strain 42) followed by inoculating PRRSVs with high- (strains 383 and LMY; Group 1) and/or low-potency (strain 415 and 380; Group 2) neutralizing antibodies for strain 42. The relative numbers of T cells were determined two, six, and eight hours post-inoculation (hpi) by flow cytometry and cytokines (IL-2, IL-6, and IL-10) were examined by enzyme-linked immunosorbent assay. Populations of CD4+, CD4−, and CD8− cells were not significantly different upon infection with Group 1 and 2 viruses in PBMCs. However, the frequency of CD8+ and CD3+ cells slightly increased eight hpi with Group 1 viruses as well as with strain 42. Those cells also produced more IFN-γ and TNF-α, and IL-10 secretion was significantly downregulated in cell supernatant infected with Group 1 viruses compared with Group 2 viruses. However, each PRRSV did not influence the level of other cytokines (IL-6 and IL-12). CD3 expression analysis suggested stronger T-cell activation in Group 1 infection. This study shows that serum neutralizing antibody titer among viruses is related to certain cytokines, suggesting that those cytokines could contribute to customized vaccine development.