Biotinylated recombinant interleukin-2. A tool for research on the interleukin-2 receptor

Recombinant interleukin-2 was biotinylated using a N-hydroxyl-succinimidyl [3H]biotin ester. The biotinylated lymphokine retained full binding and growth-promoting activities when assayed on the interleukin-2-dependent murine cell line HT-2. In preliminary studies, biotinylated interleukin-2 was used in conjunction with immunogold staining to demonstrate cell surface interleukin-2 receptors using both light and electron microscopy techniques. In addition, with rabbit anti-biotin antibodies, biotin-interleukin-2 was able to precipitate the 55 kDa IL-2 receptor from murine HT-2 cells. Thus, biotin-interleukin-2 represents a useful, non-radioactive tool for studying the structure and function of the interleukin-2 receptor.