Animal Behavior & Well Being I

Infectious diseases of both humans and farm animals are re-emerging as significant problems, because our arsenal of effective anti-infective tools is not expanding proportionally. Thus, there is an urgent need for new approaches to the treatment of infectious disease, especially in cases of drug-resistant microbes, microbes for which therapy is not available, or in cases of host immune impairment. Recently developed technologies have opened up new avenues for the use of immunotherapy with pathogen-specific antibodies. While the idea is far from new (serum therapy in the early 1900s preceded the advent of antibiotics), for the approach to be affordable, an inexpensive, abundant source of specific antibodies is required. Polyclonal antibody sources therefore are limited to chicken egg yolk antibodies (also called IgY) and bovine colostral antibodies. Numerous successful applications have been reported, ranging from treatment of rotaviral and cryptosporidial diarrhea to prophylaxis against dental caries. Monoclonal antibodies, while offering enhanced specificity, have long been disqualified, even for human treatment, due to lack of economical production systems. The recent introduction of transgenic animals and especially transgenic plants for production of therapeutic proteins has dramatically changed this perspective. Molecular farming of antibodies has made it possible to produce antibodies as complex as secretory IgA (sIgA) at a fraction (estimated at between 2 10 %) of the cost of the conventional production systems. The plantibody approach is especially attractive for the production of recombinantly simplified antibodies, the so-called single chain variable fragments (scFvs). With decreasing cost of production, the potential to tailor antibodies to very precise specifications and our increasing molecular knowledge of host-pathogen interactions, antibodies seem to have a bright future ahead as a redesigned tool for prophylaxis and treatment of infectious disease, both in animals and in humans.