Alonzo H. Ross

Production and characterization of monoclonal antibodies against human malignant melanoma.

The specific immunoreactivities of 31 monoclonal antibodies against human malignant melanoma were analyzed on a variety of malignant and nonmalignant human cells. Seven distinct groups were defined based on reactivity in radioimmunoassay and in mixed hemadsorption assay. The Group A antibody bound to 33% of short- and long-term cultured melanomas; Group B antibodies reacted with the majority of melanomas, astrocytomas, neuroblastomas, and fetal polygonal cells; and Group C antibodies bound to melanomas, teratocarcinomas, and to melanocytes grown in the presence of tumor-promoting phorbol esters. Antibodies of Groups D-G showed a less restricted binding pattern. In all groups, antibodies of IgG2b and IgM isotypes mediated complement-dependent lysis (CDC) and antibodies of IgG1, IgG2a, and IgG2b isotypes mediated antibody-dependent cell-mediated cytotoxicity (ADCC). Biochemical analysis indicated that 16 different proteins with molecular weights ranging between 28,000 and 500,000 were detected by the monoclonal antimelanoma antibodies.

Isolation and amino terminal sequencing of a novel melanoma-associated antigen

The biochemical characteristics are described for a melanoma-associated glycoprotein antigen, whose expression depends on stage of tumor progression and melanocytic differentiation. This antigen, identified using a monoclonal antibody which specifically stains melanoma cells in immunoperoxidase assay of fixed tissue sections, is synthesized as a 30,000-Da precursor and then processed to a 30,000- to 60,000-Da sialylated glycoprotein. Two-dimensional gel electrophoresis of the antigen resolved more than 20 forms, heterogeneous in both charge and molecular weight. The kinetics of post-translational processing, the sensitivity of processing to tunicamycin, and the molecular weight of the oligosaccharide chains indicate that the oligosaccharides are N-linked. Amino acid sequencing of the antigen purified by immunoaffinity chromatography and by high-pressure liquid chromatography or polyacrylamide gel electrophoresis allowed the assignment of the first 20 acids.

The nerve growth factor receptor in normal and transformed neural crest cells

Nerve growth factor (NGF) is a peptide hormone essential for the development and maintenance of sympathetic and sensory neurons. This dependence is readily demonstrated by injecting rodent embryos with anti-NGF antibodies. The resulting pups lack a functional sympathetic nervous s y ~ t e m ? ~ NGF is probably synthesized and released by the innervated tissues serving to guide the axons to the correct sites and acting as a survival factor for the neurons once the synapses are formed? NGF can also act as a differentiation factor for embryonic adrenal and pheochromocytoma cells causing neurite e~tension.~ For a subclone of a rat pheochromocytoma cell line PC12, NGF is mitogenic.6 The initial event for all of these responses is binding of NGF to specific receptors on the cell surface. A number of investigators have identified 90,000and 200,000dalton proteins as NGF receptors,7* and there have been a few reports of an additional 140,000-dalton receptor. To allow a more definitive molecular weight assignment of the NGF receptor, we prepared anti-NGF receptor monoclonal antibody (MAb)