Reactivity of 3B5 with human tissues. A) Dominant follicle (DOF, midfollicular phase) – g, granulosa; vl, vascular layer; ti, theca interna; tv, thecal vessels; te, theca externa. B) Fresh CL – gl, granulosa lutein cells; tl, theca lutein cells; v, proliferating luteal vessels. C) Mature CL – midluteal phase. D) Old CL (OCL, late luteal phase). E) Regressing CL (RCL, mid-follicular phase of the subsequent cycle). F) Corpus luteum of pregnancy (CLP, 3rd month of pregnancy) Arrowhead indicates cytoplasmic LHR immunoreactivity. G) Fallopian tube. Arrowhead indicates LHR immunoreactivity at the luminal aspects of epithelial cells. H) Endometrium (EM, late follicular phase – note stromal edema) – se, surface epithelium; g, glands; s, endometrial stromal cells. I) Staining of brain microvasculature (v) and microglial cells (arrowhead – see Fig. 8). Insets show control staining (ctr). Hematoxylin counterstain except panel F.