Blood lymphocyte numbers, essential for the development of efficient immune responses, are maintained by recirculation through secondary lymphoid organs. We show that lymphocyte trafficking is altered by the lysophospholipid sphingosine-1-phosphate (S1P) and by a phosphoryl metabolite of the immunosuppressive agent FTY720. Both species were high-affinity agonists of at least four of the five S1P receptors. These agonists produce lymphopenia in blood and thoracic duct lymph by sequestration of lymphocytes in lymph nodes, but not spleen. S1P receptor agonists induced emptying of lymphoid sinuses by retention of lymphocytes on the abluminal side of sinus-lining endothelium and inhibition of egress into lymph. Inhibition of lymphocyte recirculation by activation of S1P receptors may result in therapeutically useful immunosuppression.

Sphingosine 1-phosphate (S1P) is a bioactive lysolipid with pleiotropic functions mediated through a family of G proteincoupled receptors, S1P 1,2,3,4,5 . Physiological effects of S1P receptor agonists include regulation of cardiovascular function and immunosuppression via redistribution of lymphocytes from blood to secondary lymphoid organs. The phosphorylated metabolite of the immunosuppressant agent FTY720 (2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol) and other phosphonate analogs with differential receptor selectivity were investigated. No significant species differences in compound potency or rank order of activity on receptors cloned from human, murine, and rat sources were observed. All synthetic analogs were high-affinity agonists on S1P 1 , with IC 50 values for ligand binding between 0.3 and 14 nM. The correlation between S1P 1 receptor activation and the ED 50 for lymphocyte reduction was highly significant (p Ͻ 0.001) and lower for the other receptors. In contrast to S1P 1 -mediated effects on lymphocyte recirculation, three lines of evidence link S1P 3 receptor activity with acute toxicity and cardiovascular regulation: compound potency on S1P 3 correlated with toxicity and bradycardia; the shift in potency of phosphorylated-FTY720 for inducing lymphopenia versus bradycardia and hypertension was consistent with affinity for S1P 1 relative to S1P 3 ; and toxicity, bradycardia, and hypertension were absent in S1P 3 Ϫ/Ϫ mice. Blood pressure effects of agonists in anesthetized rats were complex, whereas hypertension was the predominant effect in conscious rats and mice. Immunolocalization of S1P 3 in rodent heart revealed abundant expression on myocytes and perivascular smooth muscle cells consistent with regulation of bradycardia and hypertension, whereas S1P 1 expression was restricted to the vascular endothelium.

TYK2 is a nonreceptor tyrosine kinase involved in adaptive and innate immune responses. A deactivating coding variant has previously been shown to prevent receptor-stimulated activation of this kinase and provides high protection from several common autoimmune diseases but without immunodeficiency. An agent that recapitulates the phenotype of this deactivating coding variant may therefore represent an important advancement in the treatment of autoimmunity. BMS-986165 is a potent oral agent that similarly blocks receptor-stimulated activation of TYK2 allosterically and with high selectivity and potency afforded through optimized binding to a regulatory domain of the protein. Signaling and functional responses in human TH17, TH1, B cells, and myeloid cells integral to autoimmunity were blocked by BMS-986165, both in vitro and in vivo in a phase 1 clinical trial. BMS-986165 demonstrated robust efficacy, consistent with blockade of multiple autoimmune pathways, in murine models of lupus nephritis and inflammatory bowel disease, supporting its therapeutic potential for multiple immune-mediated diseases.

To test the hypothesis that tolerating some subretinal fluid (SRF) in patients with neovascular agerelated macular degeneration (nAMD) treated with ranibizumab using a treat-and-extend (T&E) regimen can achieve similar visual acuity (VA) outcomes as treatment aimed at resolving all SRF.Design: Multicenter, randomized, 24-month, phase 4, single-masked, noninferiority clinical trial.Participants: Participants with treatment-naïve active subfoveal choroidal neovascularization (CNV). Methods: Participants were randomized to receive ranibizumab 0.5 mg monthly until either complete resolution of SRF and intraretinal fluid (IRF; intensive arm: SRF intolerant) or resolution of all IRF only (relaxed arm: SRF tolerant except for SRF >200 mm at the foveal center) before extending treatment intervals. A 5-letter noninferiority margin was applied to the primary outcome.Main Outcome Measures: Mean change in best-corrected VA (BCVA), and central subfield thickness and number of injections from baseline to month 24.Results: Of the 349 participants randomized (intensive arm, n ¼ 174; relaxed arm, n ¼ 175), 279 (79.9%) completed the month 24. The mean change in BCVA from baseline to month 24 was 3.0 letters (standard deviation, 16.3 letters) in the intensive group and 2.6 letters (standard deviation, 16.3 letters) in the relaxed group, demonstrating noninferiority of the relaxed compared with the intensive treatment (P ¼ 0.99). Similar proportions of both groups achieved 20/40 or better VA (53.5% and 56.6%, respectively; P ¼ 0.92) and 20/200 or worse VA (8.7% and 8.1%, respectively; P ¼ 0.52). Participants in the relaxed group received fewer ranibizumab injections over 24 months (mean, 15.8 [standard deviation, 5.9]) than those in the intensive group (mean, 17 [standard deviation, 6.5]; P ¼ 0.001). Significantly more participants in the intensive group never extended beyond 4-week treatment intervals (13.5%) than in the relaxed group (2.8%; P ¼ 0.003), and significantly more participants in the relaxed group extended to and maintained 12-week treatment intervals (29.6%) than the intensive group (15.0%; P ¼ 0.005).Conclusions: Patients treated with a ranibizumab T&E protocol who tolerated some SRF achieved VA that is comparable, with fewer injections, with that achieved when treatment aimed to resolve all SRF completely.

Naïve T cells, when activated by specific antigen and cytokines, up-regulate adhesion molecules as well as chemokine receptors on their surface, which allows them to migrate to inflamed tissues. Human studies have shown that CXCR3 is one of the chemokine receptors that is induced during T cell activation. Moreover, CXCR3-positive T cells are enriched at inflammatory sites in patients with autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. In this study, we use a mouse model of inflammation to demonstrate that CXCR3 is required for activated T cell transmigration to inflamed tissue. Using an anti- mCXCR3 antibody, we have shown that in vitro-differentiated T helper (Th) 1 and Th2 cells up-regulated CXCR3 upon stimulation with specific antigen/major histocompatibility complex. However, only Th1 cells, when adoptively transferred to syngeneic recipients, are efficiently recruited to the peritoneum in an adjuvant-induced peritonitis model. Furthermore, the neutralizing anti-mCXCR3 antibody profoundly inhibits the recruitment of Th1 cells to the inflamed peritoneum. Real-time, quantitative reverse transcriptase-polymerase chain reaction analysis demonstrates that the CXCR3 ligands, interferon (IFN)-inducible protein 10 (CXCL10) and IFN-inducible T cell alpha chemoattractant (CXCL11), are among the many chemokines induced in the adjuvant-treated peritoneum. The anti-mCXCR3 antibody is also effective in inhibiting a delayed-type hypersensitivity response, which is largely mediated by enhanced trafficking of activated T cells to peripheral inflammatory sites. Collectively, our results suggest that CXCR3 has a critical role in T cell transmigration to sites of inflammation and thus, may serve as a molecular target for anti-inflammatory therapies.