| Abstract: | Using a recently developed method of culturing T-lymphocyte colonies in agar-containing capillary tubes, the capacity of three different lymphoid extracts with lymphocyte chalone (LC) activity to inhibit colony growth was demonstrated. Sephadex fractions from a calf spleen extract were tested on the colony growth of granulocytic cells and PHA-stimulated T-lymphocytes as well as on the in vitro uptake of 3H-thymidine by bone marrow and ConA- and LPS-stimulated mouse spleen cells. The data strongly suggest that it is only the combination of several different assay systems applied to the same fractions that permits a clear-cut determination of a specific lymphocyte proliferation inhibitor like LC. |
