Coelomocytes of E. fetida were extruded from earthworms immersed for 1 minute in fluid and treated either with an electric shock (5V) or 5% ethanol. The two methods were equally efficient with regard to the number and viability of coelomocytes retrieved and did not affect animal survival. Cell viability was not affected by short contact with the extrusion fluids of wide ranges of osmolarities (10-1600 mOsm) and pH (3-11). In contrast, extreme pH (especially 11) and osmolarities (especially 22 and 600 mOsm) impaired cell viability during a few hours of in vitro incubation. Cell survival was best in L-15 medium at the neutral pH and at the osmolarity characteristic for terrestrial animals (285-320 mOsm). Coelomocyte viability after 7 hr in vitro incubation at 0, 10, 22, and 37oC was always the lowest at 37oC. Cells extruded from animals maintained at room temperature were the best vital at 22oC. Viability of the cells transferred from 22oC to 10oC for one week only was best at 10oC and equally good at 0oC and 22oC. In vitro viability of cells retrieved from earthworms maintained at 10oC for 2 or 3 weeks was significantly higher at 10oC and 0oC than at 22oC. This indicates that a relatively long-lasting (more than one week) in vivo adaptation to cold is necessary to improve coelomocyte viability at low temperatures.
A. Stankiewicz, Department of Immunology, Institute of Zoology, Jagiellonian University, R. Ingardena 6, 30-060 Krakow, Poland. E-mail: stan@zuk.iz.uj.edu.pl