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 IgG co ntent is correlated with the specific antibody production rates of bat ch hybridoma cultures. Therefore, surface associated IgG content of si ngle hybridoma cells might indicate antibody secretion rates of indivi dual cells. Moreover, the surface IgG content should reflect the patte rn of secretion rates during the cell cycle. To probe for IgG secretio n rates during the cell cycle, a double staining procedure has been de veloped allowing simultaneous flow cytometric analysis of surface IgG content and DNA content of murine hybridoma cells. Crosslinking of the surface associated immunofluorescence with the cell by paraformaldehy de fixation permits subsequent DNA staining without loss of immunofluo rescence. The optimized protocol has been used to determine the patter n of the surface IgG fluorescence as a function of the cell cycle posi tion. It is highest during the G2 + M cell cycle phase and the experim ental data are in excellent agreement with the previously predicted se cretion pattern during the cell cycle. (C) 1995 John Wiley and Sons, I nc.