Recent studies have shown that neonatal mice are competent to develop mature, Ag-specific Th1 function in situ. However, under many conditions, Th2 responses dominate in the neonate, while Th1 responses are more prevalent in adults. To compare further the immune responses of neonates and adults, we used the enzyme-linked immunospot method to measure the frequencies of primary Th1/Th2 effectors generated in situ in the spleens and lymph nodes. As assessed by the detection of IFN-gamma- or IL-4-producing cells, adults developed mixed Th1/Th2 responses in both organs. Neonatal lymph nodes contained mature frequencies of IFN-gamma- and IL-4-producing cells. In striking contrast, while mature frequencies of Th2 cells developed in neonatal spleens, virtually no IFN-gamma-secreting cells were detected. Exclusive Th2 function was observed in both BALB/c and C57BL/6 neonates, strains in which the Th2 and Th1 lineages, respectively, are favored in adults. Although Th1 effectors were virtually undetectable, the addition of rIL-12 boosted the frequency of IFN-gamma-secreting cells to adult levels. Therefore, Th1 effectors apparently developed in situ, but Th1 effector function either was not promoted or was inhibited upon subsequent exposure to the Ag in culture. Together, these results indicate that the quality of a primary Th response in neonates is strongly dependent on the site of initial Ag exposure; responses initiated in the lymph nodes are mixed Th1/Th2, whereas responses occurring in the spleen are heavily Th2 biased.
In a previous study we have demonstrated the existence of pulvinar (puv) cells which were optimally activated when a monkey executed reaching movements with his limbs (Acuña et al 1983). We now describe further observations in four Macaca nemestrina monkeys trained to perform goal directed reaching movements aimed at four different positions in space. Extracellular unit activity in the lateralis posterior (lp) and puv nuclei, together with electrooculograms were recorded during the execution of the task. Seven hundred and sixty neurons were studied in the lp-puv complex. One hundred and twenty three cells (16%) showed changes in activity related to the reaching movements. Reaching related cells fell into two categories: goal direction sensitive (28/123 = 23%) and pandirectional (95/123 = 77%). Goal direction sensitive cells showed different responses depending on the direction of the goal relative to the starting point of the movement. The responses of the pandirectional cells were independent of goal direction. The activity of the remaining cells (637/760) could not be correlated with reaching movements. In a smaller number of area 5a (PE) cells (n = 109) studied in one monkey, 82 (75%) were classified as reaching related cells. Of these, 76% (62/82) were goal direction sensitive and 24% (20/82) pandirectional. The lp-puv cells were more dependent on the intentionality of movement than area 5a cells, and not reliably activated by passive manipulation of the limb. After injection of HRP-WGA in area 5a, where the reaching cells were recorded, labeled cells and terminals were located in the lp-puv zones where reaching cells were also found.(ABSTRACT TRUNCATED AT 250 WORDS)
Experimental autoimmune orchitis (EAO) was induced in adult Wistar rats by active immunization with a testicular homogenate (TH) and adjuvants. Fifty per cent of the immunized rats developed EAO. Testicular damage became evident at 50 days after the primary immunization and increased in severity at 80 days. Phenotypic characterization of T-cell subsets (CD4+ and CD8+) and Ia+ cells was performed on cryostat sections of testis obtained from normal rats, rats immunized with adjuvant (control group) and rats immunized with TH and adjuvants (experimental group) at 50 and 80 days. Labelled cells were only detected in the interstitial area; no labelled cells were observed inside the seminiferous tubules with any of the monoclonal antibodies used (W3/25, OX-8, OX-6). A significant increase in the numbers of CD4+ and CD8+, as well as of Ia+ cells, were observed in the testis of rats with severe EAO at 80 days after the first immunization. Rats of the same experimental group without testicular damage showed no major differences compared to rats from the control group, with the exception of a lower number of CD8+ cells. Variations in the lymphocyte subsets in lymph nodes draining the site of immunization showed the opposite pattern to that observed in the testis. In conclusion, these data suggest the traffic of specifically sensitized lymphocytes from lymph nodes to the testis and an active role of CD4+, CD8+ and Ia+ cells in the pathogenesis of EAO in the rat.
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