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Biggs RM, Makou E, Lauder S, Herbert AP, Barlow PN, Katti SK. An Evaluation of the Complement-Regulating Activities of Human Complement Factor H (FH) Variants Associated With Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2022; 63:30. [DOI: 10.1167/iovs.63.12.30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Robyn M. Biggs
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
| | - Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Scott Lauder
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
| | - Andrew P. Herbert
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Paul N. Barlow
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
- School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Suresh K. Katti
- Gemini Therapeutics, Inc., Cambridge, Massachusetts, United States
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Biggs RM, Makou E, Lauder S, Herbert AP, Barlow PN, Katti SK. A Novel Full-Length Recombinant Human Complement Factor H (CFH; GEM103) for the Treatment of Age-Related Macular Degeneration Shows Similar In Vitro Functional Activity to Native CFH. Curr Eye Res 2022; 47:1087-1093. [PMID: 35282732 DOI: 10.1080/02713683.2022.2053725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 03/03/2022] [Accepted: 03/07/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE GEM103 is a recombinantly produced full-length version of the human complement factor H (CFH) under clinical investigation for treatment of age-related macular degeneration (AMD) in individuals carrying an AMD risk-associated genetic variant of CFH. This study aimed to investigate the complement pathway-related functions of GEM103 in comparison with those of native human CFH. METHODS Key biological activities of GEM103 and human serum-derived CFH (sdCFH) were compared using four independent functional assays. Assays of C3b binding and C3 convertase decay-accelerating activity (DAA) were performed by surface plasmon resonance (SPR). Cofactor activity (CA) was measured using 8-anilinonaphthalene-1-sulfonic acid as a fluorescent probe of C3b integrity. The abilities of GEM103 and sdCFH to protect sheep erythrocytes from hemolysis by CFH-depleted normal human serum were assessed colorimetrically. RESULTS In multiple SPR-based assays of C3b binding and DAA, the performance of GEM103 was consistently comparable to that of sdCFH across a range of matching concentrations. The EC50 ± SD in the fluorescence-based fluid-phase CA assay was 0.21 ± 0.06 µM for GEM103 compared to 0.20 ± 0.09 µM for sdCFH. In hemolysis assays, the EC50 value of 0.33 ± 0.16 µM for GEM103 versus 0.46 ± 0.06 µM for sdCFH were not significantly different (p = 0.81). CONCLUSIONS GEM103, a recombinant CFH developed by Gemini Therapeutics, shows activity profiles comparable to sdCFH in all complement-related assays employed in this study, suggesting that GEM103 is equivalent to the native glycoprotein in terms of its in vitro functional activity. These results support further study of GEM103 as a potential therapy for AMD.
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Affiliation(s)
| | - Elisavet Makou
- School of Chemistry, University of Edinburgh, Edinburgh, UK
| | | | | | - Paul N Barlow
- School of Chemistry, University of Edinburgh, Edinburgh, UK
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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Dekkers G, Brouwer MC, Jeremiasse J, Kamp A, Biggs RM, van Mierlo G, Lauder S, Katti S, Kuijpers TW, Rispens T, Jongerius I. Unraveling the Effect of a Potentiating Anti-Factor H Antibody on Atypical Hemolytic Uremic Syndrome-Associated Factor H Variants. J Immunol 2020; 205:1778-1786. [PMID: 32848031 DOI: 10.4049/jimmunol.2000368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/24/2020] [Indexed: 12/15/2022]
Abstract
The complement system plays an important role in our innate immune system. Complement activation results in clearance of pathogens, immune complex, and apoptotic cells. The host is protected from complement-mediated damage by several complement regulators. Factor H (FH) is the most important fluid-phase regulator of the alternative pathway of the complement system. Heterozygous mutations in FH are associated with complement-related diseases such as atypical hemolytic uremic syndrome (aHUS) and age-related macular degeneration. We recently described an agonistic anti-FH mAb that can potentiate the regulatory function of FH. This Ab could serve as a potential new drug for aHUS patients and alternative to C5 blockade by eculizumab. However, it is unclear whether this Ab can potentiate FH mutant variants in addition to wild-type (WT) FH. In this study, the functionality and potential of the agonistic Ab in the context of pathogenic aHUS-related FH mutant proteins was investigated. The binding affinity of recombinant WT FH and the FH variants, W1183L, V1197A, R1210C, and G1194D to C3b was increased upon addition of the potentiating Ab and similarly, the decay-accelerating activity of all mutants is increased. The potentiating anti-FH Ab is able to restore the surface regulatory function of most of the tested FH mutants to WT FH levels on a human HAP-1 cell line and on sheep erythrocytes. In conclusion, our potentiating anti-FH is broadly active and able to enhance both WT FH function as well as most aHUS-associated FH variants tested in this study.
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Affiliation(s)
- Gillian Dekkers
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Mieke C Brouwer
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Jorn Jeremiasse
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Angela Kamp
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | | | - Gerard van Mierlo
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | | | | | - Taco W Kuijpers
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children's Hospital, Amsterdam UMC, 1105 AZ Amsterdam, the Netherlands; and.,Department of Blood Cell Research, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Theo Rispens
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands
| | - Ilse Jongerius
- Department of Immunopathology, Sanquin Research, Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, the Netherlands; .,Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Emma Children's Hospital, Amsterdam UMC, 1105 AZ Amsterdam, the Netherlands; and
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