Figure 6. Cd84^−/− OT-II T cells are defective in adhesion to cognate B cells.

(A-B) Conjugation efficiency of pre-activated WT and Cd84^−/− OT-II T cells with OVA₃₂₃ pulsed splenic (A) CD11c⁺ DCs, mean ± SEM frequency of CD4⁺CD11c⁺ conjugates in total CD4⁺ events (n=4, representative FACS plots, right panel), (B) LPS-activated B cells, mean ± SEM frequency of CD4⁺CD19⁺ conjugates in total CD4⁺ events (n=4, representative FACS plots, right panel) (*p<0.05, **p<0.005). (C) In vivo contact durations between T cells of indicated genotypes and MD4 B cells as measured by intravital microscopy between 60–72 h after immunization with HEL-OVA in alum. Individual contact durations (left) and their distribution (right) are shown. A total of 125, 120, and 49 contacts pooled from 3 experiments for WT, Cd84^−/−, and Sh2d1a^−/− T cells, respectively. Mean contact times: WT 14.5+/−1.2 min; Cd84^−/− 8.5+/−2.1 min; Sh2d1a^−/− 3.5+/−1.6 min. The p values were calculated by nonparametric one-way ANOVA. (D) Recovery of MD4 B cells from draining lymph nodes 96 h post-HEL-OVA immunization with or without exogenous OT-II T cells of indicated genotypes. Each symbol represents 1 of 4 mice/group. Data from 1 of 3 experiments with similar results are shown.