en Infectious Disease Infectious Disease Original Article Original Article <div style="text-align: justify;">Enterotoxigenic Escherichia coli (ETEC) causes diarrhea in both humans and animals. The contaminated food and water are the most common vehicles for ETEC infection. The colonization factor antigen (CFA-1) is a fimbriae protein that promotes adherence of the ETEC strain to the epithelium of the small intestine of the host. In this study IgY proteins were produced against the CFA-1 of ETEC in immunized white leg horn chickens. The collection of antibody was found higher in 25% and 50% ammonium precipitated samples. The isolated CFA-1 protein (0.5 mg/ml) was purified by dialysis (0.42 mg/ml), gel-filtration (0.08 mg/ml), and ion-exchange chromatography (0.065 mg/ml). The CFA-1 protein obtained was submitted to pBLAST which matched with CFA-b with accession no.-AAC41415.1. The CFA-1 gene was cloned in pUC18 vector, and transformed into Escherichia coli DH5&alpha; strain. In conclusion, we have successfully purified and characterized monoclonal antibodies (IgY proteins) against CFA-1 of enterotoxigenic E. coli that may be useful for diagnosis of widely occurring Escherichia coli infections.</div> Enterotoxigenic Escherichia coli, diarrhea, colonization factor antigen 18 23 http://ibbj.org/browse.php?a_code=A-10-332-1&slc_lang=en&sid=1 Rakesh Kumar Singh rakeshsinghbt@gmail.com 10031947532846003893 10031947532846003893 No Department of Biotechnology, TNB College, Bhagalpur-812007, India. Garima Tripathi monusep@gmail.com 10031947532846003894 10031947532846003894 Yes Department of Biotechnology, TNB College, Bhagalpur-812007, India. Pawan Kumar Dubey pawandubey1981@gmail.com 10031947532846003895 10031947532846003895 No Center for Genetic Disorders, Institute of Science, Banaras Hindu University, Varanasi-221005, India.