[Immunogenicity of single-dose HBsAg-PLGA controlled release microspheres in mice].
OBJECTIVE
To investigate the level of immune response and the immune mechanism of the single-dose hepatitis B surface antigen (HBsAg)-poly (d, l)-lactide-co-glicolide acid (PLGA) microspheres in BALB/c mice.


METHODS
Three kind of HBsAg-PLGA microspheres, HBsAg-PLGA50/50-COOH microspheres, HBsAg-PLGA75/25 microspheres and HBsAg-PLGA50/50 microspheres, were prepared by double emulsion microencapsulation technique used three kinds of PLGA with different L/G ratio. The single-dose of HBsAg-PLGA microspheres was subcutaneously injected into BALB/c mice at the dose of 7.5 microg HBsAg per mouse. The conventional aluminum-adjuvant vaccine was subcutaneously injected at 0, 1 and 2 month as positive control. In certain time interval, the induced immune level of total antibody was detected by enzyme linked immunosorbent assay (ELISA). For subclass of IgG antibody and cytokines studies, the dose of HBsAg was 2.5 microg per mouse.


RESULTS
The HBsAg-PLGA microspheres could successfully induce a humoral immune response in BALB/c mice. Compared with the conventional aluminum-adjuvant vaccine, the antibody response of the HBsAg-PLGA50/50-COOH microspheres was significantly lower than the group received three injections of aluminum-adjuvant vaccine (P < 0.01) except for a higher priming response during the early 6 weeks. The results were ascribed to the relatively rapid degradation charactics of PLGA50/50-COOH polymer. The immune response for the HBsAg-PLGA50/50 microspheres and HBsAg-PLGA75/25 microspheres were comparable to the group administered with aluminum-adjuvant vaccine (P > 0.05) which was due to the sustained degradation of PLGA50/50 and PLGA75/25 polymer.


CONCLUSIONS
The HBsAg-PLGA microsphere is a promising candidate for the controlled delivery of a vaccine which does not require multiple injections.
Feng
Li
L
Department of Pharmaceutics, School of Pharmaceutical Sciences, Peking University, Beijing 100083, China.
Zhou
Xing-jun
XJ
Wang
Shi-cong
SC
Jiang
Yang
Y
Qi
Xian-rong
XR