Normal Nonhuman Primates Research Articles

Predominance of helper-inducer T cells in mesenteric lymph nodes and intestinal lamina propria of normal nonhuman primates

To define the characteristics of T cells associated with the gastrointestinal tract, the phenotypes and immunoregulatory function of T cells from mesenteric lymph node (MLN) and lamina propria lymphocytes (LPL) were compared to peripheral blood (PBL) and spleen lymphocytes in normal nonhuman primates. Mesenteric lymph node lymphocytes were characterized by a higher proportion of Leu-3 +(CD4 +) and 9.3 +(α-Tp44) lymphocytes and a lower proportion of Leu-2 +(CD8) lymphocytes than lymphocytes in other sites. LPL and MLN lymphocytes were both characterized by a higher proportion of cells having the helper-inducer phenotypes (Leu-3 +, Leu-8 −; Leu-3 +, 2H4 −) compared to PBL. A lower proportion of cells with the suppressorinducer phenotypes (Leu-3 +, Leu-8 +; Leu-3 +, 2H4 +) was found in LPL, but not in MLN lymphocytes compared to PBL. In studies of the Leu-2 + T cells, it was found that whereas PBL, spleen, and LPL contained approximately equal proportions of Leu-2 +, Leu-15 + (suppressor phenotype) and Leu-2 +, 9.3 + lymphocytes (cytolytic T-cell phenotype), the MLN T cells were predominantly Leu-2 +, 9.3 +. Furthermore, the Leu-3 Leu-2 ratio was significantly higher in MLN compared to other sites. In pokeweed mitogen-stimulated cultures, the highest helper function for Ig synthesis was found in MLN. Cells from none of the sites studied showed evidence of increased suppressor cell activity. These results show that MLN and LPL T cells in normal nonhuman primates differ from T cells in peripheral blood and spleen. While both MLN and LPL have a high proportion of T cells with the helper-inducer phenotype, cells with the suppressor-effector phenotype are infrequent in MLN, while cells with the suppressor-inducer phenotype are infrequent in LPL.

Intrinsic 5HT-immunoreactive neurons in the spinal cord of the fetal non-human primate

Serotonin (5HT) immunoreactive neurons were identified in the late-term fetal spinal cord of normal non-human primates. These neurons were distributed throughout the spinal cord, being concentrated in lamina X and the subjacent ventral median fissure, while their immunoreactive fibers and terminals innervated the zone surrounding the central canal and the ventral spinal artery. Even at this late fetal stage, the dorsal and ventral spinal gray matter was virtually devoid of any positive 5HT immunoreactivity, in contrast to that seen in the adult primate. These findings suggest that the intrinsic 5HT neurons of the primate during development may modulate CSF composition or provide cues for spinal cord differentiation rather than regulate sensorimotor functions as they do in the adult.