Figure 1. Relationship between p:I-A^b-specific CD4⁺ T cell population sizes in unimmunized and immunized mice.

(A) Gates used to identify lymphocyte-sized, non-doublet, CD90.2⁺ B220⁻ CD11b⁻ CD11c⁻, CD4⁺ T cells.

(B) Contour plots of double tetramer staining (far left) or CD44 expression (left) for CD4⁺ T cells from spleen and lymph nodes identified as in (A) from individual unimmunized B6 mice following enrichment with the indicated p:I-A^b tetramers labeled with streptavidin-PE (X- axis) or streptavidin-APC (Y-axis). The plots on the right represent similar staining for populations in spleen and draining lymph nodes 14 days after subcutaneous injection with 10 μg of the relevant peptide emulsified in CFA.

(C) Total number of tetramer-binding CD4⁺ T cells per mouse for I-A^b-bound peptides in individual unimmunized (open circles) or immunized (filled circles) mice identified as in (B). Horizontal bars indicate mean values. The depicted results were pooled from 11 independent experiments.

(D) Linear correlation between the average log₁₀ naive and effector cell number for each of the populations identified in (C).

(E) Linear correlation between the average log₁₀ effector cell number obtained by tetramer staining (X-axis) or ELISPOT (Y-axis), 14 days after subcutaneous injection of 19 peptides from (C) emulsified in CFA. The depicted results were from 1 experiment with the mean of 3 values from individual mice for each peptide for the tetramer enrichment assay and the mean of 2 values from individual mice for the ELISPOT assay.