Naturally Occurring Humoral Cytotoxicity Against Neuroblastoma (NB) Cells in Healthy Persons and Nb Patients

Abstract

A novel cytotoxic mechanism against neuroblastoma (NB) cells based on natural immunoglobulin M serum antibodies is described. The occurrence of these antibodies, which are able to induce complement-mediated cytolysis of NB cells, has been investigated in several age groups of healthy persons and in patients with NB. The cytotoxicity of serum samples has been measured in terms of propidium iodide DNA incorporation using a FACScan. The prevalence of anti-NB 1gM antibodies shows a strong age dependence characterized by a nearly complete lack in the first year of life and a steep rise up to 82% beginning with the second year of life. In the sera of 11 NB-bearing patients no cytotoxicity has been found, despite the fact that 8 of these patients were older than 1 year. These findings lead to the hypothesis that natural 1gM antibodies could play a role as an immunological control mechanism against NB.

Actin‐binding protein filamin A is displayed on the surface of human neuroblastoma cells

“…In our previous studies, we discovered the presence of anti‐NB antibodies in sera of healthy individuals including children and adults. ( 12,13 ) These naturally occurring antibodies are of the IgM class and elicit effective killing of human NB cells in vitro by both complement activation and induction of apoptosis. ( 13,14 ) Subsequent in vivo studies in nude rats with human NB xenografts demonstrated the inhibition of tumor growth by treatment with the IgM fraction from healthy adults with a high titer of natural anti‐NB IgM.…”