CRYSTALLIZATION OF INTACT MONOCLONAL-ANTIBODIES

Attempts were made to crystallize four monoclonal antibodies, one IgG(2a kappa) and three IgG(1 kappa). Using a PEG 3350 screen combined with detergents, and developed from our experiments with an IgG(2a kappa) antibody specific for canine lymphoma cells,(1,2) crystals have now been obtained of two of these four immunoglobulins, an antiphenytoin and an antiphenobarbital antibody. A complex between the antiphenobarbital antibody and its drug antigen crystallized as well. The antibody for phenytoin has, to this point, produced only clustered microcrystals, marginally suitable for X-ray analysis. Single crystals of the IgG(1 kappa) antibody against phenobarbital, however, were characterized by X-ray diffraction to be primitive monoclinic, with unit cell dimensions a = 67 Angstrom, b = 193 Angstrom, c = 74 Angstrom, and beta = 110 degrees. These crystals have an entire IgG(1 kappa) molecule as the asymmetric unit and they diffract to at least 3.2 Angstrom resolution. (C) 1995 Wiley-Liss, Inc.