This present study compares the efficacy of microsphere formulations, and their method of antigen presentation,
for the delivery of the TB sub-unit vaccine antigen, Ag85B-ESAT-6. Microspheres based on poly(lactide-coglycolide)
(PLGA) and chitosan incorporating dimethyldioctadecylammonium bromide (DDA) were prepared by either
the w/o/w double emulsion method (entrapped antigen) or the o/w single emulsion method (surface bound antigen), and
characterised for their physico-chemical properties and their ability to promote an immune response to Ag85B-ESAT-6.
The method of preparation, and hence method of antigen association, had a pronounced effect on the type of immune response
achieved from the microsphere formulations, with surface bound antigen favouring a humoural response, whereas
entrapped antigen favoured a cellular response.