The CD2-CD58 recognition system promotes adhesion and signaling and counters exhaustion in human T cells. We found that CD2 localized to the outer edge of the mature immunological synapse (IS), with cellular or artificial APC, in a pattern we refer to as a "CD2 corolla". The corolla captured engaged CD28, ICOS, CD226 and SLAM-F1 costimulators. The corolla amplified active phosphorylated Src-family kinases (pSFK), LAT and PLC-γ over T cell receptor (TCR) alone. CD2-CD58 interactions in the corolla boosted signaling by 77% compared to central CD2-CD58 interactions. Engaged PD-1 invaded the CD2 corolla and buffered CD2 mediated amplification of TCR signaling. CD2 numbers and motifs in its cytoplasmic tail controlled corolla formation. CD8 + tumor infiltrating lymphocytes displayed low expression of CD2 in the majority of colorectal, endometrial and ovarian cancer patients. CD2 down-regulation may attenuate anti-tumor T cell responses with implications for checkpoint immunotherapies.

©Operative Dentistry, 2008, 33-3, 258-264 G Moncada • E Fernández • J Martín C Arancibia • I Mjör • VV Gordan Clinical RelevanceTreating defective restorations with sealants, repair or refurbishing is an effective way to preserve and treat existing restorations. SUMMARY

Several genes in an interval of human and mouse chromosome 1 are associated with a predisposition for systemic lupus erythematosus. Congenic mouse strains that contain a 129-derived genomic segment, which is embedded in the B6 genome, develop lupus because of epistatic interactions between the 129-derived and B6 genes, e.g. in B6.129chr1b mice. If a gene that is located on chromosome 1 is altered through homologous recombination in 129-derived embryonic stem cells (ES cells) and if the resultant knockout mouse is backcrossed with B6, interpretation of the phenotype of the mutant mouse may be affected by epistatic interactions between the 129 and B6 genomes. Here, we report that knockout mice of two adjacent chromosome 1 genes, Slamf1(-/-) and Slamf2(-/-), which were generated with the same 129-derived ES cell line, develop features of lupus, if backcrossed on to the B6 genetic background. By contrast, Slamf1(-/-) [BALB/c.129] and Slamf2(-/-) [BALB/c.129] do not develop disease. Surprisingly, Slamf1(-/-) [B6.129] mice develop both auto-antibodies and glomerulonephritis between 3 and 6 months of age, while disease fully develops in Slamf1(-/-) [B6.129] mice after 9-14 months. Functional analyses of CD4(+) T cells reveals that Slamf2(-/-) T cells are resistant to tolerance induction in vivo. We conclude that the Slamf2(-/-) mutation may have a unique influence on T-cell tolerance and lupus.

Background Increasing evidence implicates the type 17 immune axis in the pathogenesis of inflammatory arthritidies including ankylosing spondylitis (AS), and targeting of the pathway in AS has shown benefit in early clinical trials1. Cells driving inflammation in this axis express the transcription factor retinoid-related orphan nuclear receptor gamma T (ROR-gt) and make the signature pro-inflammatory cytokine interleukin-17A (IL-17A)2. Digoxin, a small-molecule inhibitors of ROR-gt has proved successful in the treatment of mouse experimental autoimmune encephalomyelitis3 but the dose needed to achieve inhibition in human cells is over 100 fold greater than the toxic threshold. New non-digoxin small molecule ROR-gt inhibitors have now been developed and we explore their role in the human inflammatory arthritidies. Objectives To determine the effects of novel small molecule ROR-gT inhibitors on in-vitro peripheral blood derived Type 17 T cell responses of patients with inflammatory arthritis. Methods Blood samples were obtained from patients with AS, rheumatoid arthritis (RA) and psoriatic arthritis (PsA). CD4 positive type 17 cells were expanded from peripheral blood monocuclear cells (PBMCs) of patients with inflammatory arthritis using low strength anti-CD2/3/28 stimulation and recombinant IL-2 in a 7 day culture system. Two different ROR-gt inhibiting compounds (A & B) were added at the start of the culture system and their effects on multiple cytokine expression (IL-17A, IFN-gamma, IL-22, GM-CSF, TNF-alpha) was determined by flow cytometry using intracellular staining. IL-17A production was validated using ELISA. Results Both ROR-gt small molecule inhibitors resulted in a consistent decrease in the percentage of patient-derived IL-17A-producing CD4 T cells. Overall there was approximately a 50% reduction in IL-17A production in AS (n=24, p<0.0001. see fig). The inhibition of IL-17A was confirmed on ELISA. There was a similar level of inhibition observed in IL-17F production. IL-22/IL-17A double producing cells were also inhibited but there was no significant effect on IL-22 single producers (Th22 cells). The effects of these inhibitors seem to be specific to type-17 cytokines (IL-17A, IL-17F) since we did not observe significant effects on the total amounts of other measured cytokines (IFN-gamma, TNF-alpha, GM-CSF). We saw inhibition of IL-17A production in RA and PsA. ROR-gt compounds did not adversely affect cell viability or proliferation in our culture system. Figure 1. Effects of ROR-gt inhibitor (compound A) on PBMC-derived Th17 cells from AS, RA and PsA patients. Conclusions Our results demonstrate a consistent and specific inhibition of IL-17A responses from patient derived PBMCs using small molecule ROR-gt inhibitors. We believe these results provide a solid rationale for the testing of these compounds in clinical trials particularly in AS where the treatment options remain limited. References Baeten, D. et al. Anti-interleukin-17A monoclonal antibody secukinumab in treatment of ank...