Binding characteristics of mouse MDC:SEAP to murine thymocytes. (A) Mouse thymocytes (1 × 10⁶ cells) were incubated with increasing concentrations of mouse MDC:SEAP. Nonspecific binding was determined in the presence of 500-fold molar excess of unlabeled murine MDC. (Inset) Scatchard analyis of the binding data. (B) Competition binding of mouse or human MDC with mouse MDC:SEAP to mouse thymocytes.