Preclinical evaluation of microencapsulated CFA/II oral vaccine against enterotoxigenic E. coli

Abstract Colonization Factor Antigen (CFA/II) from enterotoxigenic Escherichia coli (ETEC) prepared under good manufacturing practices (GMP) was successfully incorporated into biodegradable poly( d,l -lactide- co -glycolide) (PLGA) polymer microspheres (BPM) under GMP and found to be safe and immunogenic when administered intraduodenally to rabbits. Following vaccination, Peyer's patch cells responded by lymphocyte proliferation to in vitro challenge with CFA/II. Also, B cells secreting specific anti-CFA/II antibodies were found in spleens following vaccination. No pathological changes were found following total necropsies of ten rabbits vaccinated with CFA/II BPM. Sixty-three per cent of the CFA/II BPM were between 5 and 10 μm diameter by volume particle size distribution; 1.17% protein content; 2.15% moisture;