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-1β, IFN-γ, 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 Vβ12 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.