DYNAMIC AND MORPHOLOGICAL RESPONSES OF DRAINING LYMPH-NODES TO SINGLE AND REPEATED APPLICATIONS OF OXAZOLONE TO THE SKIN

The responses of draining lymph nodes to repeated topical application of oxazolone were followed for a period of 3 weeks. The changes were observed by histology, autoradiography after pulse labelling, and recording of the relative number of blast cells in the paracortex, as well as morphometric procedures including estimates of paracortical weight. In the paracortex, an increased proliferative activity was observed to be merely transitory in the course of the first week and decreased thereafter to control levels. The proportion of blast cells showed a similar variation. Germinal centers and plasma cells developed by the end of the first week and persisted for the remaining part of the observation time. The B-cell activation is probably a specific reaction to oxazolone, although other factors may contribute. In the paracortex, the lasting response was difficult to detect by histology alone. The nuclear size, the cellular density and the weight of the paracortex were found to change characteristically, but these features required demonstration by morphometric procedures. © 1979 Springer-Verlag.