Immunohistochemical detection of hCD4 in organs ofvav-hCD4 and control mice. (A) Transgenic spleen with a megakaryocyte (M); (B) nontransgenic spleen; (C) transgenic heart; (D) transgenic testis; and (E) transgenic cerebellum (other brain sections were also negative). Nontransgenic brain and testis were indistinguishable from those shown, and nontransgenic heart essentially so (see text).