IL6 encodes a cytokine that functions in inflammation and the maturation of B cells. In addition, the encoded protein has been shown to be an endogenous pyrogen capable of inducing fever in people with autoimmune diseases or infections. The protein is primarily produced at sites of acute and chronic inflammation, where it is secreted into the serum and induces a transcriptional inflammatory response through interleukin 6 receptor, alpha. The functioning of this gene is implicated in a wide variety of inflammation-associated disease states, including suspectibility to diabetes mellitus and systemic juvenile rheumatoid arthritis.
IL6R encodes a subunit of the interleukin 6 (IL6) receptor complex. Interleukin 6 is a potent pleiotropic cytokine that regulates cell growth and differentiation and plays an important role in the immune response. The IL6 receptor is a protein complex consisting of this protein and interleukin 6 signal transducer (IL6ST/GP130/IL6-beta), a receptor subunit also shared by many other cytokines. Dysregulated production of IL6 and this receptor are implicated in the pathogenesis of many diseases, such as multiple myeloma, autoimmune diseases and prostate cancer. Alternatively spliced transcript variants encoding distinct isoforms have been reported.
Protein expression analysis
Strain specific IL6 expression analysis in homozygous B-hIL6/hIL6R mice by ELISA.
Serum was collected from WT (+/+) and homozygous B-hIL6/hIL6R (H/H) mice stimulated with LPS in vivo, and analyzed by ELISA with species-specific IL6 ELISA kit. Mouse IL6 was detectable in WT mice. Human IL6 was exclusively detectable in homozygous B-hIL6/hIL6R mice but not in WT mice. ND: Not detectable.
Strain specific IL6R expression analysis in homozygous B-hIL6/hIL6R mice by flow cytometry. Splenocytes were collected from WT (+/+) and homozygous B-hIL6/hIL6R mice (H/H), and analyzed by flow cytometry with species-specific anti-IL6R antibody. Mouse IL6R was detectable in WT mice. Human IL6R was exclusively detectable in homozygous B-hIL6/hIL6R mice but not in WT mice.
Experimental schedule for induction of collagen induced arthritis (CIA) and in vivo efficacy of anti-human IL6 antibody
Experimental schedule for Induction of collagen induced arthritis (CIA) in B-hIL6/IL6R mice. Mice at 11 to 12 weeks old were immunized with type II collagen (CII) in complete Freund‘s adjuvant (CFA) on day 0 and day 21. After disease occurrence, Two anti-human IL6 antibodies (in house) were administered by subcutaneous injection, Body weight and clinical score were measured twice a week after grouping. (n = 5).
In vivo efficacy of anti-human IL6 antibodies with B-hIL6/hIL6R mice
Efficacy of anti-human IL6 antibodies in B-hIL6/hIL6R mice with collagen induced arthritis (CIA) model. Mice in each group were treated with olokizumab or sirukumab produced in house. Body weight (A) and total clinical score (B) were evaluated during treatment twice a week. There was no significant change in body weight, while total clinical score increased in the groups except PBS group during days 21 to 28. It indicated that the arthritis mouse model had been constructed successfully. Total clinical score decreased in the two groups treated with anti-hIL6 antibodies. The results indicated the B-hIL6/hIL6R mice provide a powerful preclinical model for in vivo evaluation of anti-human IL6 antibodies in the experiment conditions.
H&E staining of ankle joint in CIA model of B-hIL6/hIL6R mice
Effects of anti-human IL6 antibody on arthritis histology. (A) Hematoxylin and eosin (H&E) staining. (B) Score of arthritis histology (n=5). At the end of the test, histopathological examination was performed on the joints of the extremities. G1 showed no significant abnormal change under arthroscopy. G2-G4 showed subcutaneous mixed inflammatory cell infiltration, synovitis and/or pannus formation in all or part of the joints of the extremities, joint cartilage and bone tissue destruction and other arthritic lesions, suggesting that the model was successfully established. Scores of G4 shows slight decrease demonstrats that sirukumab could relieves the inflamatory. Compared scores of G3 and G2, it seems that there is no obviously decrease after teatment with olokizumab, the dosage may be need to optimization. B-hIL6/hIL6R mice could be provide as a preclinical model for in vivo evaluation of anti-human IL6 antibodies. ND: Not detectable; (a)bone sturcture damage; (b)cartilage damage;(c)synovial hyperplasia;(d)inflammatory cell infiltration in cartilage;(e)Osteolysis and superficial cartilage erosion.