"It has been shown that some cytokines such as interlukin-2 and GM-CSF enhance the immune response when genetically fused to poor antigens or administered with antigens to animals. Accordingly a
novel fusion gene consisting of the est gene of enterotoxigenic E. coli and hgm-csf has been constructed to produce hybrid hGM-CSF::ST for induction of antibody against the ST toxin. Two genes were fused through
an eight amino acid linker containing prolin for proper folding of the hybrid protein. The fusion protein was expressed in the periplasm of E. coli and identified by Western blot using antibodies against GM-CSF and ST.
The hybrid protein was then purified and injected to rabbit. The serum of the rabbit was examined for antibody against the hybrid protein, GM-CSF and ST. The results indicated that the hybrid protein could induce the
production of antibody against both components of the hybrid. The results of this study showed that the haptens such as ST can become immunogenic by fusion to a carrier protein and GM-CSF could be a good carrier and delivery system for ST."