SOME FACTORS AFFECTING MEMBRANE IMMUNOFLUORESCENCE REACTIVITY OF BURKITT LYMPHOMA TISSUE CULTURE CELL LINES

Membrane immunofluorescence (MIF) reactivity of Epstein‐Barr virus (EBV) carrying cultured Burkitt's lymphoma (BL) cells with BL sera shows certain fluctuations from time to time, even with standard reference sera and apparently constant tissue culture conditions. In order to determine the culture conditions that are critical for this variation and to establish the optimal situation favoring the production of highly reactive cells, we studied two established BL‐derived cell lines under different conditions of initial cell number, cell density per unit volume or bottom unit area in the culture vessel, depth of the fluid phase, proportion of conditioned medium, etc. Although the two lines behaved somewhat differently, they showed better reactivity when maintained at a high concentration, as long as crowding did not entirely prevent cell multiplication. Under identical conditions of medium supply and depth of the fluid phase, more closely packed cells within a smaller bottom area of the culture vessel exhibited a better MIF reactivity than more dispersed cells. Under different conditions of growth, there was an inverse relationship between the rate of cell multiplication and the percentage of viable MIF‐positive cells. Optimal conditions with steady, high‐level reactivity have been worked out for both lines, but were different with regard to quantitative detail. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company