Lymphocyte recruitment in vaccinia virus-induced cutaneous delayed-type hypersensitivity

Our goal was to study the small lymphocytes that were recruited to cutaneous DTH lesions in order to determine if there existed a subset of small lymphocytes which preferentially migrated into cutaneous inflammatory sites rather than into lymphoid tissues. Lymphocytes were radiolabelled and injected i.v. into sensitized recipient rats on which DTH lesions were induced by the i.d. injection of vaccinia virus. Small lymphocytes, from unstimulated and antigen-stimulated LNs, migrated in large numbers to LNs but only to a modest extent to the DTH lesions. Lymphoblasts, from antigen-stimulated nodes, migrated to DTH lesions well, but poorly to normal LNs. The ratio of the radioactivity in the lesions to that in LNs was used as an index of the preferential migration of the cells. This ratio for small lymphocytes was 0.8:1, while that of lymphoblasts was 34:1. Lymphocytes from the blood and spleen were better at entering lesions than the small LNCs, and their ratio was higher. Peritoneal exudate lymphocytes induced by the i.p. injection of virus migrated very well to the DTH lesions and poorly into LNs, and produced a ratio of 130:1. The peritoneal lymphocytes that migrated into the lesions were primarily small lymphocytes. Negative selection for either surface Ig-, W3/25-, MRC OX-8- or MRC OX-6- cells had little effect on the accumulation of the cells within the DTH lesions. In conclusion, it is suggested that there exists a subset of small lymphocytes with receptors on their surfaces which cause them to migrate selectively to inflammatory sites rather than to LNs. An inflammatory exudate is a rich source of this subset of small lymphocytes, while only a small proportion of small LNCs being to this subset.