Immuno Affinity Purified Interleukin 2 (IL2) Induces B Cell Growth

Abstract

With the recent availability of immuno-affinity purified IL2 (Robb 1983) we attempted to investigate whether B cell growth can be directly influenced by this lymphokine. In view of our recent findings that large “activated” B cells are more receptive than small “resting” B cells to the growth stimulating effects of EL4 derived B cell growth factor (Mond, 1984) we undertook to study the effects of IL2 on size separated populations of B cells. B cells were prepared by a modification of the method of Leibson (1981) and then separated by counterflow Centrifugation into five size dependent fractions (Thompson, 1983). The average size of the separated B cells in the smallest sized fraction (fraction 1) was 115 µ and each successive fraction had a progressively larger mean cell volume with the largest sized (fractions) being 168 µ³. Less than 2% Thy 1.2⁺ cells were present in any of the fractions. The immuno-affinity purified IL2 used in these experiments was prepared by passing supernatant coupled with a murine monoclonal antibody reactive with human IL2. Bound IL2 was recovered by elution of the column with 1.5% acetic acid (Robb, et al 1983).