The TNF-? Vaccine Based T Domain Of DT As A Carrier Protein Inhibits Collagen-induced Arthritis In Mice

Rheumatoid arthritis is a chronic disease that causes pain,stiffness,swelling and limited motion and function of many joints.RA is the most common form of autoimmune arthritis,affecting 1 pecent of the world people.Biological inhibitors targeting TNF-? such as infliximab,adalimumab and etanercept have improved significantly the clinical outcomes of inflammatory diseases,in particular rheumatoid arthritis.However,the practical uses are limited due to high costs and high risk of antidrug antibodies response.A number of alternative strategies have been developed to circumvent these shortcomings with encouraging data demonstrated in animal models but not in human trials.In present study,we developed an epitope-scaffold immunogen targeting TNF-?,DTNF7,in which a mouse TNF-? fragment(aa 80-97)is transplanted into the transmembrane domain of diphtheria toxin(DTT)at position 89 to 96.Molecular dynamics simulation shows that TNF-? epitope(aa81-88)is entirely surface-exposed and kept in a native-like conformation.Sustained humoral response against native TNF-? was observed in mice immunized with DTNF7 and alum adjuvant.In a mouse model of rheumatoid arthritis,vaccination with alum formulated DTNF7 inhibited the development of collagen-induced arthritis.These data illustrate that DTT is a promising epitope carrier and scaffold for vaccine design targeting human self-molecules including TNF-?.Another vaccine strategie was based on the whole TNF-? molecule and a carrier protein DTT.Because active TNF-? is associate with serious toxic side effects,site-directed mutation was employed to screen mutants with decreased biological activity while three-dimensional structure and the immunogenicity are minimally perturbed.A mutant Y119 N was found consequently.When DTT was fused to N-terminus of DTT TNFY119 N through linker PGSGGSYQTPVNGGSGGSYQTPVNGGSGP,high antibody titer was generated in mice.Fusion to C-terminus of TNFY119 N significantly blocked the exposure of the immunogen and lowered the immunogenicity.The therapeutic effect of TNFY119NL2-DTT is currently underway.Taken all together,we show that DTT-based vaccine is a promising strategy for prevention and treatment of autoimmune diseases.