Earthworm coelomocytes have been used as effector cells against the human tumor target, K562. To first assess the viability of effectors, incorporation of [3H]thymidine was tested and was higher in autogeneic (A ⇔ A, self) than in allogeneic (A ⇔ B, nonself) coelomocytes. A ⇔ A showed significantly greater numbers in S, G2, or M phases than A ⇔ B coelomocytes. When A ⇔ A or A ⇔ B were cultured, no significant cell killing occurred in either, as measured in a 4-hr51Cr release assay. A ⇔ A but not A ⇔ B killed K562 target cells. Cytotoxicity was dependent upon membrane binding between small, electron-dense coelomocytes and targets; it was enhanced by adding PHA. The heat labile supernatant from A ⇔ A but not from A ⇔ B killed K562 targets after cultivation for 10 min at 22°C, but not immediately after washing. Recognition of, binding to, and killing of foreign cells in a natural killer cell-like reaction may reflect natural immunity in earthworms.
ASJC Scopus subject areas
- Cell Biology