Highly Expressed Recombinant SEB for Antibody Production and Development of Immunodetection System

Staphylococcal enterotoxins (SEs) are the second most common causal agents of food poisoning throughout the world. Staphylococcal enterotoxin B (SEB) is one of the most potent and a listed biological warfare agent. Therefore, its quick, accurate and sensitive detection is of paramount importance. But availability of sensitive and specific antibodies against SEB is the major bottleneck in the development of an immunodetection system. Therefore, in the present study seb gene was cloned and expressed in a heterologous host resulting in a yield of 92 mg pure toxin per litre of culture broth after Ni–NTA affinity purification. Antibodies raised against the recombinant toxin did not cross react with related enterotoxins and organisms that can gain access in the food. Further, a sandwich ELISA was developed to detect SEB after extraction from artificially spiked food samples like milk, orange juice, skim milk and khoya. The sandwich ELISA was able to detect SEB in the range of 0.25 to 0.49 ng/ml or g of food. The detection system developed in the present study is at least as specific and sensitive as other commercially available kits which use monoclonal antibodies.