Results of model sensitivity analysis. Tier 1 parameters are those identified as the most significant factors affecting the cumulative (14 day) output of primed CD4+ T cells when 16 of the model parameters (from Table I) are varied (See Supplementary Tables and data not shown). Tier 2 parameters are identified as significant when 12 parameters from Table I are varied. Results are listed for two sample cognate frequencies, 1:300 and 1:3000. See Supplementary Tables for details. All values shown are p< 0,01.