NHP are a small, but critical, portion of the animals studied in research laboratories. Many NHP are imported or raised at
one facility and subsequently moved to another facility for research purposes. To improve our understanding of the effects
of transportation and relocation on the NHP immune system, to minimize potential confounds associated with relocation,
and to maximize study validity, we examined the phenotype and function of PBMC in cynomolgus macaques (Macaca fascicularis) that were transported approximately 200 miles by road from one facility to another. We evaluated the phenotype
of lymphocyte subsets through flow cytometry, mitogen-specific immune responses of PBMC in vitro, and plasma levels of
circulating cytokines before transportation, at approximately 24 h after arrival (day 2), and after 30 d of acclimation. Analyses
of blood samples revealed that the CD3+ and CD4+ T-cell counts increased significantly, whereas NK+, NKT, and CD14+CD16+
nonclassical monocyte subsets were decreased significantly on day 2 after relocation compared with baseline. We also noted
significantly increased immune cell function as indicated by mitogen-specific proliferative responses and by IFNγ levels on
day 2 compared with baseline. After 30 d of acclimation, peripheral blood CD4+ T-cells and monocyte counts were higher than
baseline, whereas B-cell numbers were lower. The mitogen-induced responses to LPS and IFNγ production after stimulation
with pokeweed mitogen or phytohemagglutinin remained significantly different from baseline. In conclusion, the effects
of transportation and relocation on immune parameters in cynomolgus monkeys are significant and do not fully return to
baseline values even after 30 d of acclimation.