Figure 3. Single naïve CD4⁺ T cells from the polyclonal repertoire exhibit unique patterns of effector cell differentiation after Lm infection.

(A) Plots showing the CD45.1, CD45.2, and CD90.1 staining for LLOp:I-A^b-specific cells from B6 mice that did not receive a T cell transfer. (B) Plots showing CD45.1, CD45.2, and CD90.1 staining for LLOp:I-A^b-specific cells from day 7 Lm-infected B6 mice that received a mixture of limiting numbers of CD4⁺ T cells from CD45.1^+/+, CD45.1⁺/CD45.2⁺, and CD90.1^+/+ donor mice before infection. CD45.1^+/+, CD45.1⁺/CD45.2⁺, or CD90.1^+/+ donor-derived cells are shown in the top left, top right, and bottom panels, respectively. (C) The number (left) and Th1/Tfh/GC-Tfh composition (right) of LLOp:I-A^b-specific cells derived from 20 different donor clones identified as in (B). (D) Plots of CXCR5 and PD-1 staining for donor- or recipient-derived populations from mice described in (B). Recipient A had two different donor cell-derived populations (A1 and A2), while Recipient B had only 1 (B1). (E) Absolute numbers of clonally-derived (donor) or polyclonally-derived (recipient) Th1 (black circles), Tfh (white circles), and GC-Tfh (gray circles) LLOp:I-A^b-specific cells from day 7 Lm-infected B6 mice that received a mixture of limiting numbers of donor CD4⁺ T cells before infection. Lines connect values for the same population of LLOp:I-A^b-specific cells.