Immunogenicity and protective efficacy of a formalin-inactivated rotavirus vaccine combined with lipid adjuvants

Abstract

The immunogenicity and protective efficacy of inactivated rotavirus vaccine administered intramuscularly with lipid adjuvants; MPL ® (monophosphoryl lipid A from Salmonella minnesota) or L3 ® (monooleate/lauric acid) was evaluated in an infant mouse model. Purified and formalin-inactivated rhesus rotavirus (I-RRV) combined with one of the adjuvants were administered to female balb/c mice at 0, 4 and 8 weeks. High serum IgG antibody titers developed in all vaccinated groups; I-RRV (GMT 45,524±9,819), I-RRV-MPL ® (GMT 190,637±64,250) and I-RRV-L3 ® (GMT 126,266±27,553). The formalin-inactivation procedure preserved neutralizing epitopes and elicited high neutralizing antibody titers; I-RRV (GMT 43,053 S.E.M.±4,189), I-RRV-MPL ® (GMT 66,398 S.E.M.±20,202) and I-RRV-L3 ® (GMT 60,887 S.E.M.±10,750). All offsprings to immunized dams were protected against clinical diarrhea upon oral challenge with RRV. The IgG1/IgG2a ratio was in all immunized groups ∼1 suggesting development of a balanced Th1/Th2 response.