Figure 4: Administration of a Peptide Antibody Targeting the TILRR Functional Site Reduces Development of Atherosclerosis

(A) Fluorescence-activated cell sorting analysis of GR1+ and GR1 blood monocytes as described in the Methods from apolipoprotein E–deficient (ApoE–/–) mice on a high-fat diet (control, top) and littermates injected with a blocking anti-TILRR peptide antibody 2 times/week for 12 weeks (bottom). (B, C) Quantitation of data from experiments such as in A shows (B) high levels of GR1+ monocytes in samples from control animals (black bar) and reduced levels in TILRR antibody–injected mice (light gray bar) and (C) low levels of unactivated GR1 monocytes in control mice (black bar) and high levels in samples from TILRR antibody-injected mice (light gray bar), with no change in total levels. Data show (B) GR1+ and (C) GR1 monocytes expressed as percent of total. Values are mean ± SEM. n = 5 control mice (black bar), 5 TILRR antibody–injected mice (light gray bar). Levels in antibody-injected mice versus levels in control mice, (B) **p = 0.0065; (C) **p = 0.0064. (D) Collagen-stained sections of aortic root (top) and brachiocephalic artery (bottom) from control ApoE–/– mice (left, arrowhead shows fibrous cap) or TILRR antibody–injected mice (right). Scale bar =200 μm. (E, F) Morphometry of (E) plaque area and (F) and collagen content in the brachiocephalic artery in control (black bar) and TILRR antibody–injected (light gray bar) mice. Data are expressed as (E) plaque area × 10−3 and (F) percent area of total, and show mean ± SEM. n = 9/6 control mice, 8/6 TILRR antibody–injected mice. Levels in antibody-injected mice versus levels in control mice, (E) *p = 0.0434; (F) *p = 0.029. (G) Sections of brachiocephalic arteries as in panel D were stained using an anti–smooth muscle cell (SMC) α-actin antibody (green) and nuclear staining (DAPI, blue). Scale bar = 50 μm. (H, I) Quantitation of smooth muscle cell content in the (H) media and (I) plaques in sections as in panel (G). Data show stained area expressed as percent of total and represent mean ± SEM. n = 7 control mice (black bar), n = 5 TILRR antibody–injected mice (light gray bar), for each graph. Levels in antibody-injected mice versus levels in control mice, (H) *p = 0.0414; (I) *p = 0.0459. (J) Sections of brachiocephalic artery from control (left) and TILRR antibody treated mice (right) stained for Mac3 (macrophage marker, green). Scale bar =150 μm. (K) Quantitation of macrophage content in sections of the brachiocephalic artery as in J. Data show stained area expressed as percent of total and represent mean ± SEM. n = 8 control mice (black bar), 6 TILRR antibody–injected mice (light gray bar). Levels in antibody-injected mice versus levels in control mice, *p = 0.0214. Gr-1 = Myeloid differentiation antigen of the Ly-6 family, (Ly-6G/Ly-6C; TILRR = Toll-like and interleukin 1 receptor regulator.