Dry Mass and Cell Area Changes in Ehrlich Mouse Ascites Carcinoma Cells after Complement-Fixation Reaction Measured by Interference Microscopy^*

Ehrlich ascites carcinoma cells from Swiss mice were treated with rabbit antiserum and rabbit normal serum in the presence of complement. The dry mass changes and cell size changes, as represented by cell area changes, were measured by the interference microscope with a half-shade eyepiece and an eyepiece micrometer. The antiserum-treated cells were found to have a loss of at least 49.1 per cent of their mean dry mass, and an increase of 253.0 per cent of their cell area, at the end of a 3-hour treatment. The normal serum-treated cells had only an insignificant loss of 3.3–3.9 per cent of their mean dry mass and an 11.7 per cent decrease in their cell area.

The theory of the mode of antibody reaction is discussed, and we believe the primary effect is on the cell membrane: the permeability of the cell membrane is altered to permit the dry mass of the cell to leak out while the increased intracellular content of water causes the cell to swell.