Proof-of-concept for a virus-induced obesity vaccine; vaccination against the obesity agent adenovirus 36

Human adenovirus 36 (Ad36) is positively associated with obesity in humans and animals. Ad36 infection is characterized by increased adiposity and inflammation. To investigate the possibility that a prophylactic vaccine candidate might protect against Ad36-induced obesity and inflammation, we purified Ad36 and ultraviolet-irradiated virus to obtain a vaccine candidate. After immunizing the mice with the vaccine candidate (vaccinated group), live Ad36 was injected into mice as a challenge test. Unvaccinated mice (control group) were immunized with phosphate-buffered saline and then challenged with live Ad36. Fourteen weeks after challenge, we compared adiposity and inflammation in vaccinated and control mice. The control group showed 17% greater body weight and 20% more epididymal fats compared with the vaccinated group. In addition, the vaccinated group had decreased serum levels of pro-inflammatory cytokines, and infiltrated immune cells, especially M1 macrophages, in fat tissue. Therefore, the vaccine candidate for Ad36 was able to protect against Ad36-increased body weight and fat as well as inflammatory states after challenge. These results provide proof-of-concept for prophylactic vaccination against virus-induced adiposity.