Peripolesis is the process in which a cell attaches itself to another cell. This is differentiated from emperipolesis, which is when one cell is engulfed by another.
Peripolesis is thought to be a physiological mechanism involved in regulating some processes of immune response. It was observed between lymphocytes and macrophages following skin grafts between subjects, and after immune challenge with antigens.[1] Peripolesis was also observed in lung alveoli, where the peripolesed macrophages were not injured, but the cell membrane did appear to be temporarily altered.[2] In patients with active sarcoidosis, which is characterized by lymphocyte-macrophage cooperation, lymphocyte peripolesis appeared to occur in clusters and could last for minutes to hours. The lymphocytes could be seen moving around a macrophage while maintaining contact.[3]