alpha1-purothionin-protein--wheat and Melanoma

The cytotoxic agent purothionin purified from barley was covalently conjugated to the anti-human high-molecular-weight melanoma-associated antigen (HMW-MAA) monoclonal antibody (MoAb) 225.28S by utilizing water-soluble carbodiimide. Injection of the conjugate (0.1 mg/injection) significantly increased the life span of nude mice injected with ascitic-form human melanoma cells (Colo 38), and caused 40% inhibition on day 25 of the growth of solid-form human melanoma cells in nude mice. The effect is specific and is markedly influenced by the site of growth of tumors and by the schedule of administration of the conjugate.

Topics: Animals; Antibodies, Monoclonal; Antigens, Neoplasm; Antimicrobial Cationic Peptides; Cell Line; Cells, Cultured; Humans; Immunotherapy; Injections; Melanoma; Melanoma-Specific Antigens; Mice; Mice, Nude; Molecular Weight; Neoplasm Proteins; Neoplasm Transplantation; Plant Proteins

The toxic agent purothionin was conjugated to the monoclonal antibody 225.28S to a human high-molecular-weight melanoma-accociated antigen. The toxic conjugate displayed in vitro toxicity to cultured human Colo 38 melanoma cells as indicated by reduced uptake of 3H-thymidine following a 24-h incubation and loss of cell viability following a 7-day incubation. The effect is dose-dependent and is specific since addition of the toxic conjugate to a cultured Raji B lymphoid cells did not affect their 3H-thymidine uptake or their viability.

Topics: Antibodies, Monoclonal; Antimicrobial Cationic Peptides; Cell Survival; Cells, Cultured; DNA; Humans; Melanoma; Molecular Weight; Plant Proteins; Staphylococcal Protein A