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

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,<F>524±9</F>,819), I-RRV-MPL® (GMT 190,<F>637±64</F>,250) and I-RRV-L3® (GMT 126,<F>266±27</F>,553). The formalin-inactivation procedure preserved neutralizing epitopes and elicited high neutralizing antibody titers; I-RRV (GMT 43,053 <F>S.E.M.±4</F>,189), I-RRV-MPL® (GMT 66,398 <F>S.E.M.±20</F>,202) and I-RRV-L3® (GMT 60,887 <F>S.E.M.±10</F>,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. [Copyright &y& Elsevier]