Background In areas where helminthes infections are common, autoimmune diseases are rare. Treatment with helminthes or their ova, improved clinical findings of several autoimmune diseases. Based on the helminthes biological activity, a novel chimeric be-specific molecule was synthetized of tuftsin-phosphoryl-choline (PC)-TPC.

Objectives To study TPC treatment in established collagen induced arthritis (CIA) mice, and the mechanism of activity.

Methods Arthritis was induced in DBA male mice by immunization with collagen emulsified in TB-mycobacteria at the tail base. Boost was given 3 weeks later. Treatment with TPC started when the clinical score was 2. Cytokines were measure in culture-fluid of splenocytes in-vitro. T regulatory cells and B regulatory cells were measured by FACS. TPC effect on TLR4 expression was studied using HEKTM-mTLR4 cells system and its inhibitor. M1 shift to M2 was performed in RAW macrophages differentiated to M1 by PMA followed by LPS. TPC was added and IL-6, TNFalpha, IL-10 were tested by ELISA.

Results Starting TPC treatment of CIA mice after disease establishment, had a significant lower arthritis score in comparison with control vehicle subjected mice (i.e. TPC-6.8±0.8 vs vehicle-13.8±0.45; p<0.0001). Joints staining revealed normal joint structure in TPC treated mice, whereas, control mice treated with PBS, PC or tuftsin had severe inflamed joints. Likewise, TPC enhanced anti-inflammatory response by enhanced IL-10 secretion, reduced pro-inflammatory cytokines secretion (IL-1β, IL-17, IL-6, and TNF-α) (p<0.001). Furthermore, TPC induced expansion of splenic CD4+CD25+FOXP3+ T regulatory cells (Tregs) and IL-10+CD5+CD1d+ B regulatory cells (Bregs). The mechanism underling the TPC related immunomodulatory activity was attributed to its bi-specific activity: a) Shift of Raw cells macrophages from pro-inflammatory macrophages M1 to anti-inflammatory M2 secreting anti- IL-10 (p<0.001), through the tuftsin part of TPC. b) TPC inhibited significantly TLR4 expression by HEKTM-mTLR4 cells (p<0.02) via the phosphorylcholine end. Our data indicated that TPC significantly ameliorated established CIA by anti-inflammatory immunomodulatory activity.

Conclusions Our data may lead to a novel bi-specific self small molecule for therapy of patients with advanced RA.

Disclosure of Interest None declared