We have been working with RPE cells in our lab. In both the cell line and the primary cells we work with, we consistantly see vesicles appear post treatment. We have stained them with propidium idodie (apoptosis) and sudan black B (lipids) and neither are picked up by the vesicles. Has anyone seen these before and/or has any idea what they might be? Thank you in advance for any help! I have attached a pdf of some phase-contrast images of the vesicles in the primary RPE cells!