Expression of CD41 during mouse embryonic development.

(A) E9.5 yolk sac (ys) and embryos were subjected to wholemount staining with anti-CD41 antibody. Abundant expression of CD41 was detected in yolk sac blood islands. (B) Staining with FITC-conjugated anti-CD41 antibody (short arrows) demonstrates the presence of individual CD41⁺ hematopoietic cells inside the blood islands. Long arrows point to extraembryonic endoderm (eee) and extraembryonic mesoderm (eem). Original magnifications A, × 40; B, × 200.