The proportion of CD1-restricted and NK1.1+ cells is increased in pIV^−/− and I-Aα^−/− mice.

(A) The density plots show NK1.1 and CD1αGalCer-tetramer staining of CD4⁺, TCRβ+ T cells from pIV^+/−, pIV^−/−, and I-Aα^−/− mice. Numbers indicate the percentage of CD4⁺ T cells in each quadrant relative to the total number of cells. NK1.1−, tetramer−, CD4⁺ T cells (lower left quadrant) are reduced 10- to 15-fold in pIV^−/− and I-Aα^−/− mice. In contrast, similar percentages of NK1.1+ and tetramer+ cells are detected in the control and mutant mice. (B) The higher proportion of NKT cells in pIV^−/− and I-Aα^−/− mice leads to an increase in the numbers of Vβ8+ CD4⁺ T cells. The bar graph shows the mean percentages of Vβ8+ cells for the 3 mouse strains. Total CD4⁺ T cells comprise a higher proportion of Vβ8+ cells in pIV^−/− and I-Aα^−/− mice as compared to control pIV^+/−littermates (left). NK1.1+ CD4⁺ T cells exhibit a similar Vβ8 bias in all 3 mouse strains (right). (C) Representation of various Vβ families in CD4⁺ and CD8⁺ T cells in pIV^−/− mice and control pIV^+/−littermates. The upper bar graph indicates the mean percentage of the CD4⁺ T cells belonging to the indicated Vβ families (at least 4 mice for each data point). The higher proportion of NKT cells in the pIV^−/− mice leads to an increase in the percentage of Vβ8 and Vβ7 CD4⁺ T cells. As a result, the representation of most other families is reduced. The distribution of Vβ families in CD8⁺ T cells is identical between control and pIV^−/− mice (lower bar graph).