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AB0119 Fully Human Monoclonal Antibodies to Phosphorylcholine Inhibit Basal and Tnf-Induced IL-6 and ICAM-1 in Synovial-Like Fibroblasts from A Rheumatoid Arthritis
  1. D. Thiagarajan1,
  2. V. Malmstrom2,
  3. J. Frostegård1,
  4. R. Fiskesund1,
  5. J. Steen2,
  6. A. Frostegård1
  1. 1IMM; Unit of Immunology and Chronic Disease, Karolinska Institutet
  2. 2CMM, Department of MEdicine, Solna, Karolinska Institutet, Stockholm, Sweden

Abstract

Background Recently, we described that non-responders to anti-TNF therapy in rheumatoid arthritis (RA) had significantly lower levels of antibodies targeting phsphorylcholine (anti-PC)

Since we had observed anti-inflammatory properties of human polyclonal anti-PC vitro, we generated a panel of fully human monoclonal antibodies to PC (anti-PC mAbs).

Objectives In this study we aimed at investigating effect of anti-PC mAbs on basal and TNF-induced IL-6 secretion and ICAM-1 expression in synovial-like fibroblasts from a healthy and a RA donor.

Methods Fully human monoclonal antibodies targeting PC of IgG1 isotype were generated from healthy human donors via single-cell sorting of PC-reactive B-cells and consequent cloning/production in human embryonic kidney (HEK) cell system. Synovial-like fibroblasts from a healthy and a RA donor at passage 3 were cultured under serum-free conditions for 12 hrs, pre-incubated with 2 clones of anti-PC mAbs (A01 and E01) at 5 μg/ml for 1 hr. TNF was added at 10 ng/ml. IL-6 levels in cell culture supernatants were measured after 12 hrs by high-sensitivity commercial ELISA. ICAM-1 and VCAM-1 was analysed by flow cytomery.

Results A significant decrease in both basal and TNF-induced IL-6 level in cell supernatants of RA synoviocyte-like fibroblasts was observed with anti-PC mAbs Simultaneously, a significant decrease in surface expression of both ICAM-1 and VCAM-1 was observed. Anti PC mAbs excerted similar effect on TNF-induced Il-6 adn ICAM- 1 expression in healthy synoviocytes.

Conclusions Fully human anti-PC mAbs could be produced by single-cell sorting of PC-reactive B-cells and consequent cloning/production in a human cell system. Anti-PC mAbs inhibit both basal and TNF-induced IL-6 levels in cultured synoviocyte-like fibroblasts from rheumatoid arthrtis. Further, there was a variation in the effects between clones. Our data suggest that anti PC mAbs could be of therapeutic interest.

Disclosure of Interest D. Thiagarajan: None declared, V. Malmstrom: None declared, J. Frostegård Shareholder of: JF is named as co-inventor in patents/patent applications in relation to anti-PC, R. Fiskesund Shareholder of: RF is named as a co inventor on a pending patent application in rleation to anti OC mAbs, J. Steen: None declared, A. Frostegård Shareholder of: AF is named as a co-inventor in pending patent application in relation to anti PC

DOI 10.1136/annrheumdis-2014-eular.6090

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