Collagen minipellet as a controlled release delivery system for tetanus and diphtheria toxoid

The use of biodegradable polymer matrices as a single-dose vaccine delivery system was investigated using tetanus toroid (TT) and diphtheria toroid (D T). BALB/c mice were immunized with TT or DT in different formulations incl uding individual, in minipellet and aluminum hydroxide (alum), and the anti body responses were monitored for 48 weeks. Antigens entrapped in minipelle t elicited higher antibody responses compared to those obtained with indivi dual antigens and antigens adsorbed to alum and the antibody levels remaine d elevated over 48 weeks. In addition, minipellet formulations induced the same subclasses of antibodies induced by alum formulations. These results r aise the possibility to obtain optimal and long-lasting immune responses by a single administration of minipellet formulations. (C) 2001 Published by Elsevier Science Ltd.