Phentotypic analysis of MDC-responsive thymocytes. FACS analysis was performed on thymocytes after chemotaxis towards an optimal concentration of MDC (100 nmol/L). The upper panels show staining of freshly isolated thymocytes with CD4 and CD8 or CD3. The lower panels show staining of thymocytes that had migrated in response to MDC for the same markers. Data shown are representative of 3 separate experiments.