1
|
Patel SR, Maier CL, Zimring JC. Alloantigen Copy Number as a Critical Factor in RBC Alloimmunization. Transfus Med Rev 2023; 37:21-26. [PMID: 36725483 PMCID: PMC10023450 DOI: 10.1016/j.tmrv.2022.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022]
Abstract
RBC alloimmunization remains a significant barrier to ongoing transfusion therapy leading to morbidity, and in extreme cases mortality, due to delayed or insufficient units of compatible RBCs. In addition, the monitoring and characterization of alloantibodies, often with multiple specificities in a single patient, consumes substantial health care resources. Extended phenotypic matching has mitigated, but not eliminated, RBC alloimmunization and is only logistically available for specialized populations. Thus, RBC alloimmunization remains a substantial problem. In recent decades it has become clear that mechanisms of RBC alloimmunization are distinct from other antigens and lack of mechanistic understanding likely contributes to the fact that there are no approved interventions to prevent RBC alloimmunization from transfusion. The combination of human studies and murine modeling have identified several key factors in RBC alloimmunization. In both humans and mice, immunogenicity is a function of alloantigen copy number on RBCs. Murine studies have further shown that copy number not only changes rates of immunization but the mechanisms of antibody formation. This review summarizes the current understanding of quantitative and qualitative effects of alloantigen copy number on RBC alloimmunization.
Collapse
Affiliation(s)
- Seema R Patel
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, USA
| | - Cheryl L Maier
- Center for Transfusion and Cellular Therapies, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - James C Zimring
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, USA; Carter Immunology Center, University of Virginia, Charlottesville, VA, USA.
| |
Collapse
|
2
|
Pedroza-Escobar D, Castillo-Maldonado I, González-Cortés T, Delgadillo-Guzmán D, Ruíz-Flores P, Cruz JHS, Espino-Silva PK, Flores-Loyola E, Ramirez-Moreno A, Avalos-Soto J, Téllez-López MÁ, Velázquez-Gauna SE, García-Garza R, Vertti RDAP, Torres-León C. Molecular Bases of Protein Antigenicity and Determinants of Immunogenicity, Anergy, and Mitogenicity. Protein Pept Lett 2023; 30:719-733. [PMID: 37691216 DOI: 10.2174/0929866530666230907093339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/03/2023] [Accepted: 08/03/2023] [Indexed: 09/12/2023]
Abstract
BACKGROUND The immune system is able to recognize substances that originate from inside or outside the body and are potentially harmful. Foreign substances that bind to immune system components exhibit antigenicity and are defined as antigens. The antigens exhibiting immunogenicity can induce innate or adaptive immune responses and give rise to humoral or cell-mediated immunity. The antigens exhibiting mitogenicity can cross-link cell membrane receptors on B and T lymphocytes leading to cell proliferation. All antigens vary greatly in physicochemical features such as biochemical nature, structural complexity, molecular size, foreignness, solubility, and so on. OBJECTIVE Thus, this review aims to describe the molecular bases of protein-antigenicity and those molecular bases that lead to an immune response, lymphocyte proliferation, or unresponsiveness. CONCLUSION The epitopes of an antigen are located in surface areas; they are about 880-3,300 Da in size. They are protein, carbohydrate, or lipid in nature. Soluble antigens are smaller than 1 nm and are endocytosed less efficiently than particulate antigens. The more the structural complexity of an antigen increases, the more the antigenicity increases due to the number and variety of epitopes. The smallest immunogens are about 4,000-10,000 Da in size. The more phylogenetically distant immunogens are from the immunogen-recipient, the more immunogenicity increases. Antigens that are immunogens can trigger an innate or adaptive immune response. The innate response is induced by antigens that are pathogen-associated molecular patterns. Exogenous antigens, T Dependent or T Independent, induce humoral immunogenicity. TD protein-antigens require two epitopes, one sequential and one conformational to induce antibodies, whereas, TI non-protein-antigens require only one conformational epitope to induce low-affinity antibodies. Endogenous protein antigens require only one sequential epitope to induce cell-mediated immunogenicity.
Collapse
Affiliation(s)
- David Pedroza-Escobar
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Irais Castillo-Maldonado
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Tania González-Cortés
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Dealmy Delgadillo-Guzmán
- Facultad de Medicina, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Pablo Ruíz-Flores
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Jorge Haro Santa Cruz
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Perla-Karina Espino-Silva
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Erika Flores-Loyola
- Facultad de Ciencias Biologicas, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27276, Mexico
| | - Agustina Ramirez-Moreno
- Facultad de Ciencias Biologicas, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27276, Mexico
| | - Joaquín Avalos-Soto
- Cuerpo Academico Farmacia y Productos Naturales, Facultad de Ciencias Quimicas, Universidad Juarez del Estado de Durango, Gomez Palacio, Mexico
| | - Miguel-Ángel Téllez-López
- Cuerpo Academico Farmacia y Productos Naturales, Facultad de Ciencias Quimicas, Universidad Juarez del Estado de Durango, Gomez Palacio, Mexico
| | | | - Rubén García-Garza
- Facultad de Medicina, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | | | - Cristian Torres-León
- Centro de Investigacion y Jardin Etnobiologico, Universidad Autonoma de Coahuila, Viesca, Coahuila, 27480, Mexico
| |
Collapse
|
3
|
Howe JG, Stack G. Relationship between B-cell epitope structural properties and the immunogenicity of blood group antigens: Outlier properties of the Kell K1 antigen. Transfusion 2022; 62:2349-2362. [PMID: 36205403 DOI: 10.1111/trf.17110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/17/2022] [Accepted: 08/20/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND The immunogenicities of polypeptide blood group antigens vary, despite most being created by single amino acid (AA) substitutions. To study the basis of these differences, we employed an immunoinformatics approach to determine whether AA substitution sites of blood group antigens have structural features typical of B-cell epitopes and whether the extent of B-cell epitope properties is positively related to immunogenicity. STUDY DESIGN AND METHODS Fifteen structural property prediction programs were used to determine the likelihood of β-turns, surface accessibility, flexibility, hydrophilicity, particular AA composition and AA pairs, and other B-cell epitope properties at AA substitution sites of polypeptide blood group antigens. RESULTS AA substitution sites of Lua , Jka , E, c, M, Fya , C, and S were each located in regions with at least two structural features typical of B-cell epitopes. The substitution site of K, the most immunogenic non-ABO/D antigen, scored the lowest for most B-cell epitope properties and was the only one not predicted to be part of a linear B-cell epitope. The most immunogenic antigens studied (K, Jka , Lua , E) had B-cell epitope structural properties determined by the fewest programs; the least immunogenic antigens (e.g., Fya , S, C, c) had B-cell epitope properties according to the most programs. DISCUSSION Counter to prediction, the immunogenicity of polypeptide blood group antigens was not positively related to B-cell epitope structural features present at their AA-substitution sites. Instead, it tended to be negatively related. The AA-substitution site of the most immunogenic non-ABO/D antigen, K, had the least B-cell epitope features.
Collapse
Affiliation(s)
- John G Howe
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gary Stack
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA.,Pathology and Laboratory Medicine Service, VA Connecticut Healthcare System, West Haven, Connecticut, USA
| |
Collapse
|
4
|
Montemayor-Garcia C, Karagianni P, Stiles DA, Reese EM, Smellie DA, Loy DA, Levy KY, Nwokocha M, Bueno MU, Miller JL, Klein HG. Genomic coordinates and continental distribution of 120 blood group variants reported by the 1000 Genomes Project. Transfusion 2018; 58:2693-2704. [PMID: 30312480 DOI: 10.1111/trf.14953] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 06/25/2018] [Accepted: 07/13/2018] [Indexed: 01/25/2023]
Abstract
BACKGROUND The 1000 Genomes Project provides a database of genomic variants from whole genome sequencing of 2504 individuals across five continental superpopulations. This database can enrich our background knowledge of worldwide blood group variant geographic distribution and identify novel variants of potential clinical significance. STUDY DESIGN AND METHODS The 1000 Genomes database was analyzed to 1) expand knowledge about continental distributions of known blood group variants, 2) identify novel variants with antigenic potential and their geographic association, and 3) establish a baseline scaffold of chromosomal coordinates to translate next-generation sequencing output files into a predicted red blood cell (RBC) phenotype. RESULTS Forty-two genes were investigated. A total of 604 known variants were mapped to the GRCh37 assembly; 120 of these were reported by 1000 Genomes in at least one superpopulation. All queried variants, including the ACKR1 promoter silencing mutation, are located within exon pull-down boundaries. The analysis yielded 41 novel population distributions for 34 known variants, as well as 12 novel blood group variants that warrant further validation and study. Four prediction algorithms collectively flagged 79 of 109 (72%) known antigenic or enzymatically detrimental blood group variants, while 4 of 12 variants that do not result in an altered RBC phenotype were flagged as deleterious. CONCLUSION Next-generation sequencing has known potential for high-throughput and extended RBC phenotype prediction; a database of GRCh37 and GRCh38 chromosomal coordinates for 120 worldwide blood group variants is provided as a basis for this clinical application.
Collapse
Affiliation(s)
- Celina Montemayor-Garcia
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | | | - David A Stiles
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Erika M Reese
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Danielle A Smellie
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Debrean A Loy
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Kimberly Y Levy
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Magdalene Nwokocha
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Marina U Bueno
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Jeffery L Miller
- Genetics of Development and Disease Branch, NIDDK, National Institutes of Health, Bethesda, Maryland
| | - Harvey G Klein
- Department of Transfusion Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
5
|
Howe JG, Stack G. Relationship of epitope glycosylation and other properties of blood group proteins to the immunogenicity of blood group antigens. Transfusion 2018; 58:1739-1751. [PMID: 29770450 DOI: 10.1111/trf.14609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND The intrinsic properties of polypeptide blood group antigens that determine their relative immunogenicities are unknown. Because size, composition, charge, dose, and epitope glycosylation affect the immunogenicity of other polypeptides, we examined whether similar properties were related to the immunogenicity of blood group antigens. STUDY DESIGN AND METHODS Amino acid (AA) sequences of antithetical blood group antigens were searched for N- and O-glycosylation sites. Regression analysis was carried out to determine whether blood group protein properties, including total and ectodomain size, red blood cell (RBC) antigen site density, number of mismatched AAs between an antigen and its closest homolog, and differences in mass, charge, and hydrophobicity of the mismatched AAs, were related to immunogenicity. RESULTS The immunogenicities of non-RhD polypeptide antigens were directly related to the total and ectodomain sizes of their carrier proteins. A negative power relationship existed between RBC antigen site density and immunogenicity, such that the most immunogenic antigens had the lowest site density. The strong immunogenicity of RhD was related to the number of AA mismatches between RhD and RhCE, to their cumulative hydrophobicity and electrostatic mismatch scores, and the cumulative AA mass difference. No N- or O-glycosylation differences were predicted for antithetical or homologous antigens, other than a previously known N-glycosylation difference between K and k. CONCLUSION Epitope glycosylation appeared not to be a determinant of immunogenicity for blood group antigens, except possibly for K. The immunogenicity of blood group antigens was positively related to total and ectodomain sizes of blood group proteins and negatively related to antigen site density. Such findings should be considered hypothesis generating for future, more definitive studies.
Collapse
Affiliation(s)
- John G Howe
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Gary Stack
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut.,Pathology and Laboratory Medicine Service, VA Connecticut Healthcare System, West Haven, Connecticut
| |
Collapse
|