Chemical agents and enzymes used for the extraction of gut lymphocytes influence flow cytometric detection of T cell surface markers

Chemical agents (DTT, EDTA) and enzymes (collagenase, DNAse) are often used for the generation of a single cell suspension from tissue samples. In thi s study, flow cytometry was used to examine the effect of chemical agents a nd enzymes on the expression of cell membrane markers of T lymphocytes from tonsils and peripheral blood. Expression of CD4, CD8, CD25, CD38, L-select in, CD44, alpha E beta 7 and alpha 4 beta 7 were studied. Incubation of lym phocytes with DTT and EDTA resulted in a decrease of CD38, alpha E beta 7 a nd alpha 4 beta 7 expression. Incubation with collagenase A and DNAse resul ted in a decrease of CD25, L-selectin, alpha E beta 7 and alpha 4 beta 7. T he results of this study indicate that a careful interpretation is necessar y for phenotypic descriptions of lymphocyte populations obtained by enzymat ic isolation techniques. (C) 2000 Elsevier Science B.V. All rights reserved .