Figure 1.
Expression of CARΔ1 and wt CAR on Tg lymphocytes. (A) CAR expression does not perturb T cell development. Lymphocytes were isolated from the spleen or thymus of either non-Tg, wt CAR Tg, or CARΔ1 Tg mice, stained with fluorescent-conjugated antibodies to CAR, CD4, CD8, and/or B220, and analyzed by flow cytometry (CD4 and CD8 expression in the spleen and thymus is shown). The percentages shown for cells in each quadrant represent the average for four sets of age- and sex-matched mice. Thymic and splenic cellularity did not differ significantly between mice of the different genotypes. Average cell number ± SD (×107) for the thymus: non-Tg, 7.7 ± 3.6; CARΔ1, 8.6 ± 4.7; and wt CAR, 7.5 ± 3.4. For the spleen: non-Tg, 9.9 ± 2.3; CARΔ1, 12.0 ± 5.6; and wt CAR, 14.1 ± 1.6. (B) The expression of CAR on lymphocyte subsets. The expression of CAR on peripheral blood T cells (B220-negative lymphocytes), B cells (B220 positive), CD4+CD8+ thymocytes, or CD4−CD8− thymocytes was determined by flow cytometry as in A. The mean value of fluorescence for the entire cell population is indicated inside each histogram. (C) The CAR Tg mRNA is specifically expressed in the thymus and peripheral lymphocytes. Total RNA was isolated from the indicated tissues from either non-TG (−) or CARΔ1 Tg mice and analyzed for the expression of the human CARΔ1 transgene by Northern blotting. Lymphocyte RNA was isolated from the spleen and lymph nodes combined. The positions of RNA size markers are indicated. The expression of 28S and 18S rRNA (methylene blue stain) is shown as a loading control.