A Novel, Vasoactive Product and Plasminogen Activator from Afferent Lymph Cells Draining Chronic Inflammatory Lesions 1

Summary A vasoactive product of a cell type present in afferent and not efferent lymph has been described. The kinetics of the resultant hyperemia following intradermal injection of the material distinguish this activity from histamine, bradykinin or prostaglandin E1. Furthermore, the activity appears to be distinct from plasminogen activator and prostaglandins on the basis of studies with DFP and indomethacin. This vasoactive product may mediate blood flow alterations following antigenic challenge. A relationship between antigen-induced increased blood flow and increased lymphocyte traffic has been described for both fixed lymphoid tissue and induced cellular hypersensitivity sites. It is our contention that the regulation of the blood flow to such regions may be of fundamental importance in governing the number of inflammatory cells in an area and the rate of extravasation of blood plasma.