Collagen Type II and a Thermo-Responsive Polymer of N-Isopropylacrylamide Induce Arthritis Independent of Toll-Like Receptors

Abstract

We established and characterized an arthritis mouse model using collagen type II (CII) and a thermo-responsive polymer, poly(N-isopropylacrylamide) (PNiPAAm). The new PNiPAAm adjuvant is TLR-independent, as all immunized TLR including MyD88-deficient mice developed an anti-CII response. Unlike other adjuvants, PNiPPAm did not skew the cytokine response (IL-1␤, IFN-␥, IL-4, and IL-17), as there was no immune deviation towards any one type of immune spectrum after immunization with CII/ PNiPPAm. Hence, using PNiPAAm, we studied the actual immune response to the self-protein, CII. We observed arthritis and autoimmunity development in several murine strains having different major histocompatibility complex (MHC) haplotypes after CII/ PNiPAAm immunization but with a clear MHC association pattern. Interestingly, C57Bl/6 mice did not develop CII-induced arthritis, with PNiPAAm demonstrating absolute requirement for a classical adjuvant. Presence of a gene (Ncf1) mutation in the NADPH oxidation complex has a profound influence in arthritis and using PNiPAAm we could show that the high CIA severity in Ncf1 mutated mice is independent of any classical adjuvant. Macrophages, neutrophils, eosinophils, and osteoclasts but not mast cells dominated the inflamed joints. Furthermore, arthritis induction in the adjuvant-free, eosinophil-dependent V␤12 DBA/1 mice could be shown to develop arthritis independent of eosinophils using CII/PNiPAAm. Thus, biocompatible and biodegradable PNiPAAm offers unique opportunities to study actual autoimmunity independent of TLR and a particular cytokine phenotype profile.

Applications of polymeric adjuvants in studying autoimmune responses and vaccination against infectious diseases

“…Recently, we have developed a synthetic polymerbased poly-N-isopropylacrylamide (PNiPAAm) adjuvant for the development of collagen-induced arthritis. When collagen type II (CII) purified from rat chondrosarcoma was injected with PNiPAAm, it efficiently activated the immune response in several different mouse strains and subsequently induced arthritis [137,138]. Most importantly, PNiPAAm was found to induce the immune responses independent of toll-like receptors.…”

“…LPS is the first natural polymer that has been used as an adjuvant and its immunomodulation activity rsif.royalsocietypublishing.org J R Soc Interface 10: 20120536 [134,135] TiterMax (TM) squalene, non-ionic block polymer of polyoxypropylene and polyoxyethylene -myasthenia gravis [136] poly-N-isopropylacrylamide N-isopropylacrylamide -rheumatoid arthritis [137,138] silicones polymer of silica, carbon, hydrogen, oxygen -scleroderma, rheumatoid arthritis, Sjogren's syndrome, systemic lupus erythematosus [139,140] rsif.royalsocietypublishing.org J R Soc Interface 10: 20120536…”

Adjuvant poly(N‐isopropylacrylamide) generates more efficient monoclonal antibodies against truncated recombinant histidine‐rich protein2 of Plasmodium falciparum for malaria diagnosis

“…These adjuvants sometimes deviate from the actual immune responses, and they are also found to be associated with local and systemic toxicities [3]. A careful consideration of antigen conformation as well as in depth knowledge of adjuvant effects on antigens are required to ensure the preservation of antigen epitopes [4, 5]. An adjuvant that is biocompatible can preserve antigen epitopes from degradation upon delivery into animals and is capable of inducing a long lasting antibody response as well as cell mediated immunity [5, 6].…”

“…A careful consideration of antigen conformation as well as in depth knowledge of adjuvant effects on antigens are required to ensure the preservation of antigen epitopes [4, 5]. An adjuvant that is biocompatible can preserve antigen epitopes from degradation upon delivery into animals and is capable of inducing a long lasting antibody response as well as cell mediated immunity [5, 6]. In addition, CFA administration for generation of mAbs often leads to hypersensitivity and pain to the animals and it is banned in the Western countries.…”

“…The exact mechanism of action of this polymer is yet to be elucidated, but it is known to precipitate over the antigen. When the polymer‐antigen complex is injected into the host, the antigen is released slowly over a long period of time [5–7]. This polymer is biocompatible and does not show toxicities under in vivo conditions.…”