Therapeutic Role Of A Vaccine Targeting RANKL And TNF-α On Collagen-induced Arthritis

Objective Combination of two agents targeting tumor necrosis factor-α (TNF-α) andthe receptor activator nuclear of NF-κB ligand (RANKL) has been proved highlysuccessful in experimental autoimmune arthritis models and rheumatoid arthritis(RA) patients. This raises a possibility whether a single agent simultaneouslytargeting TNF-α and RANKL proves a potential therapeutic opportunity. This studyaimed to design a vaccine and evaluate its therapeutic effects reducing inflammationand bone resorption through inhibiting overexpression of both TNF-α and RANKLin RA mice model.Methods Standard molecular biological techniques were used to establish thevaccine to generate human RANKL-TNF-like core fusion protein (RTFP-2). Theimmunogenicity of RTFP-2vaccine was determined by measuring the titer ofspecific antibodies using sandwich enzyme linked immunosorbant assay (ELISA).The neutralizing effects of specific antibodies were detected by TNF-α mediatedcytotoxicity and RANKL induced osteoclastogenesis assay in vitro. The dualfunctions of vaccine against TNF-α and RANKL in vivo were assessed using theexperimental cachexia and hypercalcemia models. The therapeutic effects of vaccinewere evaluated using collagen induced arthritis (CIA) mice.Results High titers of antibodies against human TNF-α and RANKL were elicited atfour weeks after immunization of the vaccine in mice. The antiserum induced byRTFP-2vaccine decreased TNF-α mediated apoptosis of L929cells to41%incomparison with90%in positive controls. In addition, the antiserum completely abrogated the differentiation of bone marrow progenitors to mature osteoclasts invitro. Immunization with the RTFP-2also reduced the mortality of TNF-α inducedcachexia in mice from56%to28%. The RANKL-mediated hypercalcemic effectswere significantly attenuated in RTFP-2vaccined mice compared with control mice.Furthermore, RTFP-2vaccine significantly mitigated the incidence and severity ofCIA via inhibition of inflammation and bone resorption.Conclusion Our results showed that the immunization of RTFP-2ameliorates thesymptoms of CIA mice through targeting TNF-α and RANKL, suggesting that thevaccine may provide a potential possibility to treat inflammatory bone diseases suchas RA.