Recombinant mutagenic 3ABC protein and monoclonal antibody for quality-control testing in foot-and-mouth disease vaccines.

To achieve the goal of performing quality control on vaccines for foot-and-mouth disease several steps were performed in this study. First, the gene that encodes the 3ABC region of the A24 Cruzeiro strain (which is used in vaccine production) was amplified. Second, to improve protein stability, the 3ABC protein was mutated at the 3Cpro catalytic site and cloned the amplification products in the pET-SUMO expression vector. In the third step, the resulting recombinant protein was tested, which the polyclonal antibody recognized, with the semi-purified viral 3ABC protein using an immunoassay test. Fourth, the muted recombinant protein was used to produce a monoclonal antibody. Of the 217 clones obtained, two of them that were particularly stable (mAb2D3 and mAb3D12) were selected to work with. One showed better results, as characterized by immunoassay (ELISA), Western blotting, spot synthesis, and sequencing methodologies; it also showed high reactivity against the 3ABC protein. This kind of monoclonal antibodies, which was considered as immunochemical inputs, have been used in industrial processes as part of quality-control procedures, to evaluate the elimination of the 3ABC protein so as to ensure regulatory approval of the vaccine. They have also been used in immunological tests to distinguish infected from vaccinated animals.