Figure 5: Themis2 sets the threshold for B cell activation by soluble and low-abundance membrane-bound antigen.
From: Themis2 lowers the threshold for B cell activation during positive selection
(a) Percentage of CD69+CD86+ activated wild-type and Themis2−/− IgHEL B cells following 16-h stimulation with sHEL (left) or sDEL (right). Data are representative of six (sHEL) and three (sDEL) independent experiments and comparison by unpaired t test. *P < 0.05, **P < 0.01. (b) The expression of CD69 (left) and CD86 (right) on wild-type and Themis2−/− IgHEL B cells following 16-h activation with sHEL. Comparison by unpaired t test. **P < 0.01. (c) Percentage of wild-type and Themis2−/− IgHEL B cells activated (CD69+CD86+) following 16-h stimulation with anti-IgM F(ab')2 (left) or LPS (right). Data are representative of six experiments. (d) pBMN retrovirus expressing mHEL variants linked to three tandem intracellular GFP molecules was stably transfected into NIH-3T3 cells, which were incubated overnight with CD45.2 and CD45.1 allotype-marked WT:WT or WT:Themis2−/− IgHEL B cells. The percentage of activated IgHEL B cells (CD69+CD86+) following overnight incubation with NIH-3T3 cell clones expressing different low levels of mHEL (two clones), and variants mHEL2X and mHEL3X (two clones each). Data are representative of three separate experiments with different clones. Symbols represent separate cultures and bars show means from triplicate assays. The mean levels of mHEL expression on each clone relative to untransfected cells are displayed below the x axis and were calculated from flow cytometric staining with the anti-HEL antibody HyHEL9.
