To investigate lymphocyte participation in wound healing, the migration of T lymphocyte subsets into healing wounds and subcutaneously implanted polyvinyl alcohol sponges was studied. Frozen sections of 5-, 7-, and 10-day-old incisional wounds and sponges from Lewis rats were stained with mouse anti-rat monoclonal antibodies. Cellular staining to OX1 (all leucocyte), W3/25 (helper/effector T lymphocytes), and OX8 (suppressor/cytotoxic T lymphocytes) was quantitated in two arbitrarily defined areas based on maximal cellular infiltration: the superficial wound, down to and including the papillary dermis, and the deep wound, the reticular dermis. Five-day wounds were significantly more cellular than 10-day wounds in the deep portion (p less than 0.05) and somewhat more cellular in the superficial section (p less than 0.10). Approximately 2:1 W3/25 to OX8 ratios were noted for wound strips on all days. At 5 and 10 days there are twice as many W3/25 and OX8 labeled cells in the deep wound as in the superficial portion. At 7 days there is a peak in surface W3/25 and OX8 lymphocytes, whereas the deep population remains constant. Seven- and 10-day sponge granulomas demonstrate ratios similar to the wound strips (5-day sponge lymphocytic infiltration was insufficient to count). The data demonstrate that lymphocyte subpopulation participation in wound healing is a dynamic and distinctive process.