The effect of nerve growth factor and its antibody on mast cells in vivo.

Repeated subcutaneous administration of nerve growth factor (NGF) into newborn rats caused an increase in number and size of free and tissue-adherent mast cells (MCs). In vivo and in vitro autoradiographic studies show that MCs exhibit specific binding sites for NGF. Peritoneal MCs of adult rats exposed to high titers of endogenous (autoimmunization) and exogenous NGF antibodies showed severe cytological alterations and decreased in number. Light and electron microscopic studies revealed that MC destruction took place slowly (7-10 days) and required continual exposure to high titers of NGF antibodies. The role played by NGF in the hematopoietic cell lineage is at present under study in our laboratory.