Time Course of Macromolecule Synthesis in Human Lymphocyte Cultures Stimulated by Antilymphocyte Globulin and Phytohemagglutinin

Abstract

The macromolecule synthesis induced by antilymphocyte globulin (ALG) and phytohemagglutinin (PHA) was studied in human lymphocyte cultures. The preparation and resulting characteristics of a rabbit antihuman lymphocyte globulin (RAHLG) are described. Pulse treatment of lymphocytes with RAHLG or PHA induced a wave of macromolecule synthesis. DNA synthesis showed a maximum after 45–50 h in culture for both substances. RNA synthesis was similar in the initial stages for both systems but reached a maximal peak value after 15–20 h for RAHLG cultures, while PHA cultures maintained a maximal level after 20–25 h. Protein synthesis showed a maximal value for RAHLG cultures after 22–24 h and for PHA after 46–48 h. The differences support the idea that lymphocytes transformed by ALG attain a degree of maturation or biological responsiveness different from lymphocytes transformed by PHA. At the same time, initial similarities in the time course of macromolecule synthesis indicate that ALG and PHA may wholly or partly act on the same receptor system.