Expression of nerve growth factor receptors by human peripheral blood mononuclear cells

In the rat, nerve growth factor (NGF) has been shown to affect immune reactivity by binding to cell surface receptors on a subpopulation of splenic mononuclear cells. This binding occurs in a specific and saturable fashion to what appear to be low‐affinity (type II) NGF receptors (NGFR). Immunofluorescence studies here showed that NGFR are also present on a proportion of human peripheral blood mononuclear cells (PBMC). Equilibrium binding studies demonstrated that the binding of NGF to its receptors on PBMC occurs with a single equilibrium binding constant (mean) of 2.11 × 10⁻⁹ M. The number of receptors per cell was determined to be approximately 6.94 × 10³ receptors/cell. These results would suggest a role for NGF in the regulation of immune function in man, as well as in animals.