Colonization Factor Antigen I, an Enterotoxigenic Escherichia coli Colonization Factor, Exhibits Therapeutic Significance

Abstract

Colonization factor antigen I (CFA/I) is the prominent colonization factor present in one-third of enterotoxigenic Escherichia coli (ETEC) isolates. The effect of egg-yolk derived CFA/I specific immunoglobulin Y (IgY) antibodies on growth and adhesion parameters of human ETEC expressing CFA/I was studied. Native CFA/I was purified from ETEC strain and used for production of CFA/I specific IgY antibodies by immunizing chicken. CFA/I specific IgY antibodies significantly reduced growth of ETEC in the culture conditions. The adherence phenomenon of ETEC to HT-29 cell monolayer, a colon adenocarcinoma cell line, was assessed by incubating bacteria in the presence of CFA/I specific IgY antibodies and control (non immunized) antibodies. Bacteria adhered to cell monolayers were quantitatively assessed and expressed as colony forming units. Data presented in the present article on the bacterial growth and adherence to intestinal epithelial cells in the presence of CFA/I specific IgY antibodies suggests that it significantly reduced ETEC adherence to HT-29 cells. These results highlight the therapeutic importance of CFA/I and IgY antibodies as a means of passive immunization against ETEC infection. Data generated using IgY antibodies strengthens the efforts on developing an alternative therapy to antibiotics in controlling and preventing ETEC infections.