Biodegradable Microspheres: Vaccine Delivery System for Oral Immunization

Abstract

The potential of biocompatible and biodegradable microspheres as a controlled release oral vaccine delivery system has been examined. Orally-administered 1-10 11m microspheres composed of poly (DL-Iactide-co-glycolide) were specifically taken up into the Peyer's patch lymphoid tissue of the gut, where those ~ 5 !lID remained for up to 35 days. Microspheres < 5 11m disseminated within macrophages to the mesenteric lymph nodes and spleen. In contrast to soluble staphylococcal enterotoxin B toxoid, oral immunization with enterotoxoid in microspheres induced circulating toxin-specific antibodies and a concurrent secretory IgA anti-toxin response in saliva and gut fluid.

Pili in microspheres protect rabbits from diarrhoea induced by E. coli strain RDEC-1

“…over negative control was significant (Figure 1 In living tissue, filaments composed of lactide-50 coglycolide copolymers are non-antigenic, non-pyrogenic, non-toxic' 9 , and degrade over time at rates largely determined by the molar ratios of the lactide to glycolide" . The inertness and orderly degradation of Elo-dge et al 4 reported markedly increased antianimals I week after vaccination (Figure 4). In both the enterotoxin IgA titres in gut fluids of mice orogastrically AF/RI-MS vaccinated and unvaccinated groups, a given microspheres incorporating staphylococcal enterovigorous antibody response, to about the same level, toxin B compared with titres in mice given soluble toxin.…”

The Evolution and Value of Diphtheria Vaccine

“…In relation to oral immunization, Peyer's patch M cells were reported to be able to transport biodegradable microspheres less then 5 μm in diameter [37]. Therefore, the development of efficient needle-free, oral vaccine delivery systems-a hope long held by all involved with immunization-needs to consider the particle-transporting capability of the M cell.…”

Biodegradable Vaccine Microcapsules for Systemic and Mucosal Immunization against RVF and VEE Viruses

“…We, and others, have shown that the systemic injection of staphylococcal enterotoxin B toxoid (14)(15)(16)(21)(22)(23), influenza vaccine (24), simian immunodeficiency virus (SIV) vaccine (22) or ovalbumin (25,26) encapsulated in 1-10 pxn DL-PLG microspheres results in a strongly potentiated antibody response. In the case of SEB toxoid, mice immunized with 50 gtg of vaccine in microspheres mounted a neutralizing plasma anti-toxin response which was equivalent in level and duration to that induced by the same dose of toxoid in complete Freund's adjuvant (CFA), but without an inflammatory response (14).…”

“…DL-PLG microspheres have also been found to be an effective vehicle for mucosal immunization via the oral (15,16,21,23) and intratracheal (22,23) routes. This activity is attributable to the protection against nonspecific and specific proteolytic degradation provided by the encapsulation, as well as the enhanced and targeted delivery of the intact vaccine into the MALT.…”

“…This activity is attributable to the protection against nonspecific and specific proteolytic degradation provided by the encapsulation, as well as the enhanced and targeted delivery of the intact vaccine into the MALT. This adsorption of microspheres into the MALT from the lumen of the gut or respiratory tract is through a phagocytic-like mechanism restricted to particles of <10 gim in diameter (15,16,21).…”