Dose-response of lymphocyte carbohydrate metabolism to phytohaemagglutinin

In human blood lymphocytes the following parameters of carbohydrate metabolism were measured at 30 min intervals during 4 h incubations: lactate, pyruvate, and glycerol + glycerol-1- P accumulation, the levels of ATP + ADP, 2,3- P 2-glycerate, and glucose-1,6- P 2, and the incorporation of inorganic phosphate into acid-soluble nucleotides. The response of these parameters to commercially available, unpurified PHA showed a maximum at 50–100 μg/ml (except lactate accumulation which showed a plateau beginning at 100 μg/ml). With PHA purified according to Rigas et al. [16], similar results were found: the maxima were reached at lower PHA concentrations (5–40 μg/ml) but the degree of stimulation was the same as with unpurified PHA. The maximal thymidine incorporation into acid-insoluble material after 4 days was found for unpurified PHA at 12–200 μg/ml and for purified PHA at 6–12 μg/ml. Stimulation of this parameter by purified PHA was 2–3 times as high as by unpurified PHA. The titre of lymphoagglutinating activity of the purified PHA was 10 times as high on a weight basis as that of unpurified PHA.