Therapeutic potential of egg yolk antibodies for treating Clostridium difficile infection

Herein we present evidence for the therapeutic potential of colonization factor (CF)-specific egg yolk antibodies (IgY) for potentially treating acute and recurring Clostridium difficile infection (CDI) in humans. The study involved cloning, expressing as 6xHis-tagged proteins in Escherichia coli, and Ni-affinity purifying three previously identified CFs (FliC, FliD and Cwp84) from C. difficile. The recombinant CF antigens were then used to immunize Leghorn chickens and CF-specific IgY antibodies were prepared from their eggs. The specificity and titre of the resulting C. difficile CF-specific IgY antibodies were assessed by ELISA and Western immunoblotting techniques. The antibodies were also screened for their ability to inhibit C. difficile adherence to human colon-derived T84 cells, and, based on these findings, one of them (FliD-specific IgY) was evaluated for its potential to prevent C. difficile-mediated morbidity and mortality in Syrian hamsters. The results revealed that purified FliD-specific IgY significantly protected hamsters from C. difficile strain 630 infection relative to control animals treated with carbonate buffer alone or IgY produced from unimmunized chicken eggs. The results suggest that egg yolk preparations obtained from chickens immunized with recombinant C. difficile CFs may represent another safe and cost-effective treatment option in humans suffering from acute or recurring CDI.