A rapid method for screening myeloma immunoglobulins for binding activity is described, based on the principle that low energy interactions between immunoglobulins and haptens are relatively frequent and may be used as indicator systems for finding other interactions of higher energy. Amino groups on partially hydrolyzed nylon screen discs are used as initiators for the polymerization of DL-Serine N-carboxyanhydride to polyserine whiskers. Immunoglobulins are coupled by glutaraldehyde to the whiskers, and the discs are incubated with a bank of nineteen radioactive haptens and antigens. Seven out of 10 myeloma immunoglobulins each bound one or more of these radioactive ligands with K0 of between 1 × 102 and 1 × 103 liters/mole. Non-radioactive prospective antigens were tested for their capacity to inhibit the binding of radioactive ligands.

NEW is a human IgG myeloma protein whose three dimensional structure at 2.8 Å resolution is completed and whose structure at 1.8 Å resolution is partially completed. An antigen was required to identify the immunoglobulin-binding region. The method led to the finding that 2-methyl, 3-phytyl 1,4 napthoquinone (Vit. K1) bound to Fab fragment of NEW with a K0 of 1.7 × 105 liters/mole.

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This work was supported by Grants AI-08614 and AM-1003 from the United States Public Health Service and by the American Heart Association.

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