The 43-kDa band showed varying intensity depending on the samples, and a less reactive band at 55 kDa could also be observed.
The 35-kDa band was decreased on the percoll-washed sperm extract but was highly enriched in cytoplasmic droplets while the other bands remained at the same level (Fig. 7). This 35-kDa band was also found in the CEF and in the vesicles.
Anti-lactadherin-PAS6/7 reacted slightly with the 50-kDa and 35-kDa bands in sperm, and a 43-kDa band was also visible in PBS-washed sperm but decreased after washing with Percoll. An equivalent 43-kDa band and the 50-kDa band were retrieved in cytoplasmic droplets and in the caudal fluid (Fig. 8). Similar results were obtained when ejaculated sperm extracts were used instead of cauda epididy-mal sperm extracts (not shown).
All these findings indicated that none of the immuno-reactive proteins found in the vesicles were present on mature sperm extracts and that only three of the five antibodies cross-reacted between the cytoplasmic droplets and the vesicles, suggesting no direct relationships between the sperm and the vesicles.