Large empty vesicles adjacent to the Golgi were generally unlabeled. The surfaces of microvilli protruding from the apical surface of principal cells were encrusted with gold particles that were also present in the duct lumen, where they had a random distribution (Fig. 1F). Membrane-bound vesicles could not be positively identified in the lumen and gold particles in patterns consistent with the presence of such vesicles were not apparent. In the corpus and cauda epididymidis, the plasma membranes of spermatozoa were heavily labeled with gold particles, especially on cross sections of the fla-gellum (Fig. 1H). Ventolin oral inhaler
Binding of 2D6 McAb to Spermatozoa from Different Levels of the Epididymis
There was no detectable binding of 2D6 McAb to immature spermatozoa from the proximal caput epididymidis. However, the proportion of spermatozoa that were 2D6 positive increased progressively in a distal direction from the distal caput to the cauda epididymidis (Fig. 2). Although a single peak of labeled cauda spermatozoa was present in the example shown in Figure 2, a bimodal distribution was frequently obtained, indicating heterogeneity in the strength of signal. Heterogeneity was more apparent in sperm samples collected from the distal caput and proximal corpus epididymidis, presumably because a certain amount of time is necessary to expose all spermatozoa to newly secreted glycoproteins.
FIG. 2. FACS analysis of spermatozoa collected from different regions of the epididymis after staining with 2D6 McAb/FITC-RAM. Control spermatozoa from the cauda were stained with FITC/RAM only (i.e., omitting the first layer). As spermatozoa pass through the epididymis, they bind increasing amounts of 2D6 McAb, as shown by a progressive increase in fluorescence intensity from region 1 (proximal caput) to region 6 (cauda).