MONOCLONAL-ANTIBODIES TO A ZINC-BINDING PROTEIN OF RAT PANETH CELLS

Paneth cells are morphologically well characterized but their function has been not elucidated. Previously, we identified and purified a 90 KD zinc-binding protein (ZBPP-1) in rat intestine that was localized t o Paneth cell granules, consistent with their high zinc content. To fu rther elucidate the structure and function of ZBPF-1, we immunized Bal b/c mice with purified ZBPP-1 and identified four independent monoclon al antibodies (MAb) producing MAb ZIP-1 (IgM), ZIP-2 (IgG(1)), ZIP-3 ( IgM), and ZIP-4 (IgM). Immunohistochemistry (IHC) and immunoelectron m icroscopy (IEM) with these MAb showed positive staining of Paneth cell cytoplasmic granules. MAb ZBPP-1 also stained a population of mononuc lear cells in the lamina propria of digestive tract mucosa and a few c ells in spleen, presumably a subset of macrophages. These MAb will pro vide a useful tool to study the function of Paneth cells in human heal th and disease, since they crossreacted with human intestinal Paneth c ells and mucosal mononuclear cells.