Distribution of neutral maltase activity in mononuclear cells from different human lymphoid organs

Neutral maltase activity has been determined in purified monocytes, T and B lymphocytes from human peripheral blood and major lymphoid organs. In peripheral blood as in all lymphoid organs studied, neutral maltase activity was found to be significantly higher in monocytes than in B lymphocytes. Neutral maltase activity was never detected in T lymphocytes whatever the methods used for their purification. Furthermore, in each case studied, B lymphocyte fractions represented all the activities measured in unseparated lymphocytes. Neutral maltase thus appears to be the first enzymatic marker useful for the recognition and characterisation of B lymphocytes.