Therapeutic Potential of Shark Anti-ICOSL VNAR Domains is Exemplified in a Murine Model of Autoimmune Non-Infectious Uveitis

Abstract

Induced costimulatory ligand (ICOSL) plays an important role in the activation of T cells through its interaction with the inducible costimulator, ICOS. Suppression of full T cell activation can be achieved by blocking this interaction and has been shown to be an effective means of ameliorating disease in models of autoimmunity and inflammation. In this study, we demonstrated the ability of a novel class of anti-ICOSL antigen-binding single domains derived from sharks (VNARs) to effectively reduce inflammation in a murine model of non-infectious uveitis. In initial selections, specific VNARs that recognized human ICOSL were isolated from an immunized nurse shark phage display library and lead domains were identified following their performance in a series of antigen selectivity and in vitro bioassay screens. High potency in cell-based blocking assays suggested their potential as novel binders suitable for further therapeutic development. To test this hypothesis, surrogate anti-mouse ICOSL VNAR domains were isolated from the same phage display library and the lead VNAR clone selected via screening in binding and ICOS/ICOSL blocking experiments. The VNAR domain with the highest potency in cell-based blocking of ICOS/ICOSL interaction was fused to the Fc portion of human IgG1 and was tested in vivo in a mouse model of interphotoreceptor retinoid-binding protein-induced uveitis. The anti-mICOSL VNAR Fc, injected systemically, resulted in a marked reduction of inflammation in treated mice when compared with untreated control animals. This approach inhibited disease progression to an equivalent extent to that seen for the positive corticosteroid control, cyclosporin A, reducing both clinical and histopathological scores. These results represent the first demonstration of efficacy of a VNAR binding domain in a relevant clinical model of disease and highlight the potential of VNARs for the treatment of auto-inflammatory conditions.

Anti-ICOSL New Antigen Receptor Domains Inhibit T Cell Proliferation and Reduce the Development of Inflammation in the Collagen-Induced Mouse Model of Rheumatoid Arthritis

“…Solid-phase, phage display library antigen selections were carried out as detailed previously [ 49 ] using MaxiSorp immunotubes (Nunc, 444474) coated with 1–0.1 μ g/ml antigen in PBS pH 7.4. Predecorated biotinylated antigen bead selection protocols were adopted from our previous work [ 42 ]. Outputs from each selection round were screened for antigen-specific binders by monoclonal phage and periplasmic extract ELISAs against human or mouse ICOSL and unrelated protein controls at 1 μ g/ml in PBS coating concentration.…”

“…The completion of a successful phase I clinical study in SLE patients and phase II in Sjogren's syndrome patients (both conducted by Amgen Inc.) demonstrated efficacy of the human anti-ICOSL mAb, prezalumab [ 40 , 41 ]. ICOSL and its importance in antibody-mediated disease have also been verified in several preclinical models of human disease including RA, SLE, and uveitis [ 32 , 36 , 42 – 46 ] as well as in other models of arthritis (proteoglycan-induced arthritis (PGIA) and glucose-6-phosphate isomerase- (G6PI) induced arthritis), exemplifying the utility of anti-ICOSL-binding domains in the treatment of this immune disorder [ 44 , 47 , 48 ]. We have previously isolated VNAR domains from an immunised Ginglymostoma cirratum (nurse shark) library, which block the ICOS/ICOSL interaction, and went on to demonstrate their efficacy in a mouse model of noninfectious uveitis [ 42 ].…”

The ICOSL Expression Predicts Better Prognosis for Nasopharyngeal Carcinoma via Enhancing Oncoimmunity

“…Importantly, the growing understanding of ICOSL biology has now been translated into its use as a viable therapeutic target. Successful completion of phase I clinical studies of patients with systemic lupus erythematosus and phase II clinical trials of patients with Sjogren's syndrome (both performed by Amgen Inc.) demonstrated the effectiveness of human anti-ICOSL mAb prezalumab [15,16]. e importance of ICOSL and its role in antibody-mediated diseases has also been confirmed in preclinical models of several human diseases including RA, SLE, and uveitis [17,18].…”

Diagnostic and therapeutic potential of shark variable new antigen receptor (VNAR) single domain antibody

“…According to their results, the isolated VNAR clone had the ability to identify rhTNFα and neutralize it in vitro. Therefore VNAR Therapeutic [64] was suggested to be potentially developed as immunotherapeutic drug for the diseases by suppressing the over secretion of pro-inflammatory cytokine in the body [17]. On the other hand, anti-idiotypic binders have been proven as robust tools to determine pharmacokinetic studies of therapeutic antibodies and cancer vaccines development.…”