Abstract
R-binder is one of the binding proteins for vitamin B12. It appears to inhibit bacterial growth by competing for the vitamin with bacteria. We investigated the localization of R-binder in human fallopian tube immunohistochemically. Positive staining for R-binder was seen in epithelium of their isthmus (8 of 19 cases, 42%) and ampulla (18 of 27 cases, 67%). Staining in the nonciliated secretory cells was seen in the apical membranes with frequent and intense cytoplasmic immunoreactivity. The ciliated cells showed the staining mainly in the cilia. Tubal fluid was also positive for R-binder. The data suggest that R-binder plays a role in local defense mechanisms in the fallopian tube as in other organs.
