In vitro and in vivo evaluations of PLGA microsphere vaccine formulations containing pDNA coexpressing hepatitis B surface antigen and Interleukin-2.
OBJECTIVE
DNA-based vaccines encoding viral antigens have been shown to elicit immune responses in animal models. In this study, a plasmid DNA (pDNA) coexpressing the middle envelope protein of hepatitis B virus (HBV) and Interleukin-2 (IL-2) was incorporated into Poly (D,L-lactic-co-glycolic acid) (PLGA) microspheres and three different formulations were investigated for their potential as a vaccine delivery system.


METHODS
Emulsion solvent evaporation methods of water-in-oil-in-water (w/o/w) and oil-in-water (o/w) were used to generate three different formulations in which PLGA microspheres contained pDNA either encapsulated within or adsorbed onto the microspheres.


RESULTS
In vaccine formulation A2, prepared using the (w/o/w) method, pDNA was encapsulated within the microspheres. The other two formulations (B2 and B2a) were prepared using the (o/w) method and B2 contained pDNAs encapsulated within the microspheres while B2a contained pDNAs adsorbed onto the microspheres. pDNA loading efficiencies of A2, B2 and B2a were determined to be 15%, 25% and 45%, respectively. In vitro release of pDNAs from microspheres was evaluated for a 45-day period with no conformational changes and A2 displayed slower release than that of the B2 and B2a. When mice were immunized from anterior tibialis muscle using A2, B2 and B2a formulations containing 100 microg pDNA, antibody responses were detected for 6 months in mice sera.


CONCLUSIONS
Although all PLGA microsphere formulations containing pDNA elicited antibody responses by the end of the 6th month, the antibody titers were found to be higher with B2 and B2a formulations in comparison to A2 formulation and the naked pDNA in saline.
Eratalay
Aydan
A
Faculty of Pharmacy, Department of Pharmaceutical Biotechnology, Hacettepe University, Ankara, Turkey.
Coşkun-Ari
F Filiz
FF
Oner
Filiz
F
Ozcengīz
Erkan
E
D000818:Animals; D000917:Antibody Formation; D002214:Capsules / Q000737:chemistry*; D004247:DNA / Q000008:administration & dosage* / Q000235:genetics; D015870:Gene Expression; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000276:immunology; D007114:Immunization; D007376:Interleukin-2 / Q000235:genetics* / Q000276:immunology; D019344:Lactic Acid / Q000737:chemistry*; D008297:Male; D051379:Mice; D010957:Plasmids / Q000008:administration & dosage / Q000235:genetics; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D014612:Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology
D002214:Capsules; D006514:Hepatitis B Surface Antigens; D007376:Interleukin-2; D014612:Vaccines; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D004247:DNA