Since single-chain antibodies are of small molecular size, they are
especially suited for heterologous expression in bacteria, yeast
and also plants. The scFv BA11 is such an antibody. In vitro
studies demonstrated that scFv BA11 prevents the adhesion of
F4-armed ETEC to the intestinal wall of pigs and, therefore, might
prevent from the development of the "postweaning diarrhea (PWD)" of
piglets. Heterologously expressed scFv BA11 might find diagnostic
and therapeutic application.