抄録
Spleen cells from mice at various stages of immune response to sheep erythrocytes were separated into fractions by the density gradient method with gum acacia and properties of fractionated cells were scrutinized. Low density fractions included most of antibody-forming cells and their precursors, and showed high synthetic activities of DNA, RNA and protein. The highest density fraction included antigen-reactive cells. A serial density change of immunocompetent cells after priming was discussed.
