Figure 4.

Dermal endothelium in old individuals shows reduced expression of adhesion molecules. Histological sections (6 µm) from skin injected with C. albicans (n = 5 young, 6 old) at day 3 after injection were stained with antibody to CD31 to highlight dermal capillary loops and endothelial adhesion molecules E-selectin VCAM-1 and ICAM-1. (A) Double immunofluorescence staining of representative biopsies for one young and one old individual showing CD31 (green) and E-selectin (red). Capillary loops expressing adhesion molecules appear yellow (merge). This staining was repeated on biopsies of skin 3 d after C. albicans injection in five different young and five different old subjects. The collective results are shown in B. The graph shows percentage of capillary loops expressing E-selectin and the horizontal line indicates the mean (**, P = 0.008, young vs. old, Mann-Whitney test). (C) VCAM-1 (red) and CD31 (green) expression by skin biopsies taken 3 d after C. albicans injection. Representative staining of one young and one old subject is shown. These experiments were performed on four young and five old subjects, and the collective results are shown in D. Graph shows the percentage of capillary loops expressing VCAM-1; each symbol represents an individual, and lines indicate the mean (*, P = 0.015, young vs. old). (E) ICAM-1 (red) and CD31 (green) immunofluorescence staining of skin biopsies from one representative young and one representative old individual 3 d after C. albicans injection. These experiments are representative results of staining that was performed in five young and five old subjects. Bars, 100 µm.