Nanogram doses of alum-adjuvanted HBs antigen induce humoral immune response in mice when orally administered.
Mucosal immunity elicited by plant-based and other orally administered vaccines can serve as the first line of defense against most pathogens infecting through mucosal surfaces, but it is also considered for systemic immunity against blood-borne diseases such as hepatitis B (HB). Previous oral immunization trials based on multiple administration of high doses of HBs antigen elicited an immune response; however, a reproducible and long-lasting immunization protocol was difficult to design. The objective of this study was to evaluate the effect of dose and timing of orally delivered alum-adsorbed antigen on the magnitude of the anti-HBs humoral response. Mice were immunized orally by gavage intubation or parenterally by intramuscular injection three times, once every 2 weeks, with doses of 5, 50, or 500 ng alum-adjuvanted HBsAg. A low dose (10 ng) of HBsAg was orally administered three times in different time intervals: 2, 4, 6, and 8 weeks. The three consecutive 5-ng oral doses of the antigen induced immune response at the protective level (>or=10 mIU/ml), significantly higher than the reaction elicited by three 50 or 500 ng doses. In contrast, intramuscular delivery of these doses did not differ significantly; however, they induced a five to six times higher immune response than oral immunization. The 8-week period between each of the three oral immunizations appeared to be favorable to the anti-HBs humoral responses compared with the shorter schedules. The results presented here clearly identify the importance of low doses of antigen administered orally in extended intervals for a significantly higher anti-HBs response. This finding provides some indications concerning the strategy of orally administered vaccines, including plant-based ones.
Kapusta
Józef
J
Institute of Biotechnology and Antibiotics, 05-216 Warsaw, Poland.
Pniewski
Tomasz
T
Wojciechowicz
Jacek
J
Bociag
Piotr
P
Płucienniczak
Andrzej
A
D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000284:Administration, Oral; D000534:Alum Compounds / Q000008:administration & dosage*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000008:administration & dosage*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D056724:Immunity, Humoral / Q000187:drug effects*; D007115:Immunization Schedule; D007273:Injections, Intramuscular; D051379:Mice; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000008:administration & dosage; D013997:Time Factors; D014614:Vaccines, Synthetic / Q000008:administration & dosage
D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic; C041524:aluminum sulfate