Surface IgG content of murine hybridomas: Direct evidence for variation of antibody secretion rates during the cell cycle.

Previous experiments have shown that population average surface lgG content is correlated with the specific antibody production rates of batch hybridoma cultures. Therefore, surface associated lgG content of single hybridoma cells might indicate antibody secretion rates of individual cells. Moreover, the surface lgG content should reflect the pattern of secretion rates during the cell cycle. To probe for lgG secretion rates during the cellcycle, a double staining procedure has been developed allowing simultaneousflow cytometric analysis of surface lgG content and DNA content of murine hybridoma cells. Crosslinking of the surface associated immunofluorescence with the cell by paraformaldehyde fixation permits subsequent DNA staining without loss of immunofluorescence. The optimized protocol has been used to determine the pattern of the surface lgG fluorescence as a function of the cell cycle position. It is highest during the G2+M cell cycle phase and the experimental data are in excellent agreement with the previously predicted secretion pattern during the cell cycle. (c) 1995 John Wiley & Sons Inc.