Abstract
Rat mast cell granules and the plasma membrane fractions were obtained by the homogenization of highly purified rat mast cells and their isolation in a Percoll or sucrose gradient respectively. Immuno-stainings of non-stimulated rat mast cells, compound 48/80 or calcium ionophore A 23187-stimulated rat mast cells, the granules and the plasma membrane fractions were performed with a monoclonal antibody, M 6764, which recognizes HNK-1 epitope. HNK-1 epitope was present in rat mast cells and the granules, but not in the plasma membrane fractions. The granules fixed with glutaraldehyde showed ring-like figures by immunostaining with M 6764. Rat mast cells and the granules treated with chloroform-methanol after fixation were also densely stained with M 6764. Western blot analysis of rat mas tcells and the granule homogenates with M 6764 antibody showed broad protein bands ranging from 100 to 250 KDa.
These results showed the presence of HNK-1 epitope in rat mast cell granules. This HNK-1 epitope could be a glycoprotein.
