Antigenic specificity in the E-rosette augmentation reaction

The antigen reactivity of murine T-lymphocytes can be detected by their formation of a lymphokine that augments the formation of E-rosettes by normal human lymphocytes and sheep erythrocytes. Aspects of the specificity of E-rosette augmentation (ERA) were investigated with spleen cells of mice immunized with proteins or contact-sensitizers. The antigen dose-response curves in ERA were bell-shaped, with peak reactivity at optimal antigen concentrations and complete inhibition with moderate antigen excesses of 5-10 times the optimum. Optimal ERA was antigen-specific, spleen cells reacting only with molecules containing the immunizing determinant. Inhibition with moderate excess was also antigen-specific but great excess of antigen (100 times the optimum) was non-specifically suppressive. The mechanism of specific suppression by moderate excess of antigen appears to be related to the mode of its presentation to lymphocytes by accessory cells. The property of T-lymphocytes, reacting with a single defined determinant, to be inhibited specifically by moderate excess of any antigen containing this determinant, suggests a method of analysis of complex antigens.