REAGGREGATION OF INSECT CELLS IN VITRO. I. ADHESIVE PROPERTIES OF DISSOCIATED FAT-BODY CELLS FROM DEVELOPING SATURNIID MOTHS

¹ The Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138

1 . Cells dissociated from the fat-body of developing saturniid moths underwent rapid reaggregation when subjected to rotary agitation in blood plasma.

2. The rate and degree of aggregation was unaffected by low temperature or the presence of inhibitors such as dinitrophenol or cycloheximide.

3. Normal aggregation also occurred when plasma from different developmental stages or different silkworm genera was substituted.

4. When the proportion of plasma in the medium was reduced to less than 40 per cent. the degree of aggregation as measured by the size of aggregates progressively declined. No aggregation took place in physiological saline.

5. Cell adhesion was found to depend on a plasma factor which was non-dialyzable, heat-labile. inactivated by trypsin and insoluble in distilled water.

6. Vertebrate proteins (liver extract, serum albumin, or alpha. beta, or gamma globulins) could not be substituted for the plasma factor.

7. Cell adhesion also required the presence of either calcium or magnesium ions. These ions precipitated with the active proteinaceous material in amounts sufficient for reaggregation.