Immuno-protection Of Inactivated Murine Cytomegalovirus Vaccine And Adjuvant In Type 1 Diabetic Mice

Human cytomegalovirus(HCMV)is a ubiquitous human pathogen and can cause severe diseases or even death in infants and immunocompromised individuals,such as organ transplant recipients and HIV-infected patients.HCMV infection has always been a global health concern.Type 1 diabetes is an autoimmune disease.The patients who have defects in immunity are liable to be infected by various pathogens.Studies have shown that HCMV infection could increase the mortality rate in type 1 diabetic patients.However,there is no licensed HCMV vaccine for clinical use at present.In our previous study we have proved by using mouse model the good protection provided by inactivated murine CMV(MCMV)vaccine.Are the people with diabetes more susceptible to HCMV?Is inactivated vaccine also able to provide the effective protection for the diabetic?In this study,we explored these two issues with chemical-induced type 1 diabetic mouse model.In this study,male BALB/c mice were treated with streptozotocin(STZ)to induce type 1 diabetes.Healthy mice and diabetic mice were infected with different doses of virulent MCMV.Then the spleens of some mice were harvested for detection of virus titer,and survival was recorded for calculation of the 50%lethal dose(LD50)of the virus.The results showed the LD50 were 1.64×105 PFU in healthy mice,and 0.24×105PFU in diabetic mice.When mice were infected with the same dose of MCMV,the virus titers in both spleens and SG of diabetic mice were significantly higher than in healthy mice as the time passed.It showed that diabetic mice were more susceptible to MCMV infection than health mice.In addition,we prepared inactivated MCMV vaccine by MCMV by propagating the virus in NIH-3T3 cells,inactivating with formalin.The diabetic and healthy mice were injected i.p.respectively,with the vaccine at a dose of 0.25,1.0 or 4.0 ?g alone or adjuvanted with MF59 or Al(OH)3.Mice unimmunized or injected i.p.with only Al(OH)3 or MF59 were set as controls.Twenty days after 2 times(at a 3-week interval)of injection,mice sera were collected for detection of serum specific IgG antibodies by enzyme-linked immunosorbent assay(ELISA).Then the mice were challenged i.p.with a lethal dose of MCMV.Mice spleens and SGs were harvested 4 days and 21 days,respectively,post-infection for evaluating the virus titers,and the body weight loss survival of mice during 21 days post-infection were recorded.The results showed that the lower levels of IgG antibodies were induced in diabetic mice.Compared with the healthy mice,the diabetic need about fourfold dose of inactivated vaccine for inducing the same level of IgG antibodies.Both MF59 and Al(OH)3 adjuvants significantly enhanced the antibody responses to the vaccine in both diabetic and health mice.When the inactivated vaccine was immunized alone,4.0?g dose afforded the health mice with effective protection,but failed to protect the diabetic mice.When Al(OH)3 adjuvant was added to the vaccine,1.0?g dose afforded the health with effective protection,and 4.0?g dose was needed for the diabetic for effective protection.When MF59 adjuvant was added to the vaccine,0.25?g could protect all the mice,with survival rates in the health and in the diabetic were 100%and 50%,respectively;moreover,4?g dose could raise survival rate of the diabetic up to 87%?In conclusion,inactivated vaccine plus adjuvant could provide the diabetic effective protection for lethal MCMV infection.