Figure 1.

Kinetics of antigen-specific precursor frequencies during the primary and secondary response in vivo. Mean fold expansion of antigen-specific CD4^high Vβ8⁺ and Vβ8⁻ T cells during the primary and memory response to SWM 110–121, starting at day 3 after primary immunization for the baseline precursor frequency. The total number of antigen-specific T cells present at each given time point was determined by LDA as shown in Table and described in Materials and Methods. The mean total number of antigen-specific T cells used to determine the expansion of antigen-specific T cells was the result of two or three independent LDA experiments. The expansion was then calculated by dividing the mean total number of antigen-specific T cells present on a given day by the number of antigen-specific precursor cells present in day 3 cultures after primary immunization.