Figure 4.

T and B lymphocyte compartment alterations during atherosclerosis. (A) Total leukocyte number in the aorta of 33–35 wk old C57BL/6, ApoE ^−/− and ApoE ^−/− (WD for 20 wk) mice. Cells were liberated from the aortic tissues and the total leukocyte number was determined (n = 14–23 mice). Mean is indicated by horizontal bar. *, P < 0.05; **, P < 0.01. (B) T and B lymphocyte compartments in C57BL/6, ApoE ^−/− and ApoE ^−/− (WD) mice. Cell suspensions from aortas of C57BL/6 (n = 12, white bar), ApoE ^−/− (n = 26, gray bar) and ApoE ^−/− (WD) (n = 21, black bar) mice were stained with Abs against CD45, TCRβ (left), and CD19 (right). The number in the quadrants represents the percentage of positive cells. All plots were gated on CD45⁺ cells. (C) Total T and B lymphocyte numbers in the aorta of C57BL/6, ApoE ^−/− and ApoE ^−/− (WD) mice were calculated from the total cell number and the percentage of each population. Results are means ± SE (n = 12–26). **, P < 0.01. (D) L-selectin–dependent lymphocyte homing into the atherosclerotic aorta. C57BL/6 and L-selectin ^−/− splenocytes were labeled with either CFSE or CMTMR, mixed in equal number, and injected i.v. into ApoE ^−/− (WD) recipient mice. Aortas were collected after 24 h and stained with Abs against CD3, CD19, and CD45. Homing of L-selectin ^−/− lymphocytes (gray bars) is expressed as the percentage of C57BL/6 lymphocyte homing (100%, black bars). Results show mean ± SE from at least four recipients from at least three independent experiments. **, P < 0.01. (E) B (left) and T (right) cells form organized lymphoid tissue in the adventitia of ApoE ^−/− (WD) mice. Paraffin-embedded sections (5 μm) were stained with Abs against CD20 and CD3, respectively, and counterstained with hematoxylin. Isotype-control Abs showed no staining (not depicted). L, neointimal lesion. (F) MECA-79 is expressed in LN (top), but not in lymphoid tissue in the aortas of ApoE ^−/− (WD) mice. Isotype-control Abs showed no staining (not depicted).