Abstract: Four hybridomas secreting monoclonal antibody (McAb) against bovine immunoglobulin G (IgG) were developed by fusion of spleen cells from immunized BALB/C mice with SP2/0 myeloma cells, and they were named as 2F6, 5E3, 9C6 and 9H8. The McAbs secreted by all four hybridomas were identified as IgG1 subtype with a titer of 5.12 × 106. Both 5E3 and 9H8 recognized the heavy chain Fc fragment of bovine IgG. 2F6 recognized the light chain Fab fragment of bovine IgG, and 9C6 recognized the heavy chain Fab fragment of bovine IgG. The McAb from 9C6 could react with both IgG1 and IgG2. The cross-reactivity between 9C6 and goat IgG, sheep IgG, rabbit IgG, bovine IgM, casein, β-lacto globulin, lactoferrin, bovine serum albumin, ovalbumin or fish gel was less than 1%. The affinity constant of 9C6 was 8.92 × 108 L/mol.

Key words: bovine immunoglobulin G, monoclonal antibody, hybridoma, cross-reactivity, affinity