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Annual Review of Cell and Developmental... Oct 2020Innate and adaptive immune responses decline with age, leading to greater susceptibility to infectious diseases and reduced responses to vaccines. Diseases are more... (Review)
Review
Innate and adaptive immune responses decline with age, leading to greater susceptibility to infectious diseases and reduced responses to vaccines. Diseases are more severe in old than in young individuals and have a greater impact on health outcomes such as morbidity, disability, and mortality. Aging is characterized by increased low-grade chronic inflammation, so-called inflammaging, that represents a link between changes in immune cells and a number of diseases and syndromes typical of old age. In this review we summarize current knowledge on age-associated changes in immune cells with special emphasis on B cells, which are more inflammatory and less responsive to infections and vaccines in the elderly. We highlight recent findings on factors and pathways contributing to inflammaging and how these lead to dysfunctional immune responses. We summarize recent published studies showing that adipose tissue, which increases in size with aging, contributes to inflammaging and dysregulated B cell function.
Topics: Animals; Antibody Formation; B-Lymphocytes; Gastrointestinal Microbiome; Humans; Immunosenescence; Inflammation; Polymorphism, Single Nucleotide
PubMed: 33021823
DOI: 10.1146/annurev-cellbio-011620-034148 -
Frontiers in Immunology 2019This treatise describes the development of immunology as a scientific discipline with a focus on its foundation. Toward the end of the nineteenth century, the study of... (Review)
Review
This treatise describes the development of immunology as a scientific discipline with a focus on its foundation. Toward the end of the nineteenth century, the study of immunology was founded with the discoveries of phagocytosis by Elias Metchnikoff, as well as by Emil Behring's and Paul Ehrlich's discovery of neutralizing antibodies. These seminal studies were followed by the discoveries of bacteriolysis by complement and of opsonization by antibodies, which provided first evidence for cooperation between acquired and innate immunity. In the years that followed, light was shed on the pathogenic corollary of the immune response, describing different types of hypersensitivity. Subsequently, immunochemistry dominated the field, leading to the revelation of the chemical structure of antibodies in the 1960s. Immunobiology was preceded by transplantation biology, which laid the ground for the genetic basis of acquired immunity. With the identification of antibody producers as B lymphocytes and the discovery of T lymphocytes as regulators of acquired immunity, lymphocytes moved into the center of immunologic research. T cells were shown to be genetically restricted and to regulate different leukocyte populations, including B cells and professional phagocytes. The discovery of dendritic cells as major antigen-presenting cells and their surface expression of pattern recognition receptors revealed the mechanisms by which innate immunity instructs acquired immunity. Genetic analysis provided in-depth insights into the generation of antibody diversity by recombination, which in principle was shown to underlie diversity of the T cell receptor, as well. The invention of monoclonal antibodies not only provided ultimate proof for the unique antigen specificity of the antibody-producing plasma cell, it also paved the way for a new era of immunotherapy. Emil Behring demonstrated cure of infectious disease by serum therapy, illustrating how clinical studies can stimulate basic research. The recent discovery of checkpoint control for cancer therapy illustrates how clinical application benefits from insights into basic mechanisms. Last not least, perspectives on immunology progressed from a dichotomy between cellular-unspecific innate immunity and humoral-specific acquired immunity, toward the concept of complementary binarity.
Topics: Allergy and Immunology; Animals; Antibody Formation; History, 20th Century; History, 21st Century; Humans; Immunity, Cellular; Immunity, Innate
PubMed: 31001278
DOI: 10.3389/fimmu.2019.00684 -
Journal of Pharmaceutical Sciences May 2019Protein therapeutics have drastically changed the landscape of treatment for many diseases by providing a regimen that is highly specific and lacks many off-target... (Review)
Review
Protein therapeutics have drastically changed the landscape of treatment for many diseases by providing a regimen that is highly specific and lacks many off-target toxicities. The clinical utility of many therapeutic proteins has been undermined by the potential development of unwanted immune responses against the protein, limiting their efficacy and negatively impacting its safety profile. This review attempts to provide an overview of immunogenicity of therapeutic proteins, including immune mechanisms and factors influencing immunogenicity, impact of immunogenicity, preclinical screening methods, and strategies to mitigate immunogenicity.
Topics: Animals; Antibodies; Antibody Formation; Humans; Proteins
PubMed: 30599169
DOI: 10.1016/j.xphs.2018.12.014 -
Cell Jan 2023Antibody responses are characterized by increasing affinity and diversity over time. Affinity maturation occurs in germinal centers by a mechanism that involves repeated...
Antibody responses are characterized by increasing affinity and diversity over time. Affinity maturation occurs in germinal centers by a mechanism that involves repeated cycles of somatic mutation and selection. How antibody responses diversify while also undergoing affinity maturation is not as well understood. Here, we examined germinal center (GC) dynamics by tracking B cell entry, division, somatic mutation, and specificity. Our experiments show that naive B cells continuously enter GCs where they compete for T cell help and undergo clonal expansion. Consistent with late entry, invaders carry fewer mutations but can contribute up to 30% or more of the cells in late-stage germinal centers. Notably, cells entering the germinal center at later stages of the reaction diversify the immune response by expressing receptors that show low affinity to the immunogen. Paradoxically, the affinity threshold for late GC entry is lowered in the presence of high-affinity antibodies.
Topics: Antibody Affinity; Germinal Center; B-Lymphocytes; Antibody Formation; Antigens
PubMed: 36565698
DOI: 10.1016/j.cell.2022.11.032 -
Immunity Aug 2023Highly effective vaccines elicit specific, robust, and durable adaptive immune responses. To advance informed vaccine design, it is critical that we understand the...
Highly effective vaccines elicit specific, robust, and durable adaptive immune responses. To advance informed vaccine design, it is critical that we understand the cellular dynamics underlying responses to different antigen formats. Here, we sought to understand how antigen-specific B and T cells were activated and participated in adaptive immune responses within the mucosal site. Using a human tonsil organoid model, we tracked the differentiation and kinetics of the adaptive immune response to influenza vaccine and virus modalities. Each antigen format elicited distinct B and T cell responses, including differences in their magnitude, diversity, phenotype, function, and breadth. These differences culminated in substantial changes in the corresponding antibody response. A major source of antigen format-related variability was the ability to recruit naive vs. memory B and T cells to the response. These findings have important implications for vaccine design and the generation of protective immune responses in the upper respiratory tract.
Topics: Humans; Influenza Vaccines; Antibody Formation; Antibodies, Viral; T-Lymphocytes; Antigens; Organoids; Influenza, Human
PubMed: 37478854
DOI: 10.1016/j.immuni.2023.06.019 -
Cell Host & Microbe Aug 2016Antibody production is a metabolically demanding process that is regulated by gut microbiota, but the microbial products supporting B cell responses remain incompletely...
Antibody production is a metabolically demanding process that is regulated by gut microbiota, but the microbial products supporting B cell responses remain incompletely identified. We report that short-chain fatty acids (SCFAs), produced by gut microbiota as fermentation products of dietary fiber, support host antibody responses. In B cells, SCFAs increase acetyl-CoA and regulate metabolic sensors to increase oxidative phosphorylation, glycolysis, and fatty acid synthesis, which produce energy and building blocks supporting antibody production. In parallel, SCFAs control gene expression to express molecules necessary for plasma B cell differentiation. Mice with low SCFA production due to reduced dietary fiber consumption or microbial insufficiency are defective in homeostatic and pathogen-specific antibody responses, resulting in greater pathogen susceptibility. However, SCFA or dietary fiber intake restores this immune deficiency. This B cell-helping function of SCFAs is detected from the intestines to systemic tissues and conserved among mouse and human B cells, highlighting its importance.
Topics: Animals; Antibody Formation; B-Lymphocytes; Cell Differentiation; Dietary Fiber; Fatty Acids, Volatile; Fermentation; Gastrointestinal Microbiome; Gastrointestinal Tract; Gene Expression Regulation; Metabolic Networks and Pathways; Mice, Inbred C57BL
PubMed: 27476413
DOI: 10.1016/j.chom.2016.07.001 -
Cell Jan 2020Repeated exposure to pathogens or their antigens triggers anamnestic antibody responses that are higher in magnitude and affinity than the primary response. These...
Repeated exposure to pathogens or their antigens triggers anamnestic antibody responses that are higher in magnitude and affinity than the primary response. These involve reengagement of memory B cell (MBC) clones, the diversity and specificity of which determine the breadth and effectiveness of the ensuing antibody response. Using prime-boost models in mice, we find that secondary responses are characterized by a clonality bottleneck that restricts the engagement of the large diversity of MBC clones generated by priming. Rediversification of mutated MBCs is infrequent within secondary germinal centers (GCs), which instead consist predominantly of B cells without prior GC experience or detectable clonal expansion. Few MBC clones, generally derived from higher-affinity germline precursors, account for the majority of secondary antibody responses, while most primary-derived clonal diversity is not reengaged detectably by boosting. Understanding how to counter this bottleneck may improve our ability to elicit antibodies to non-immunodominant epitopes by vaccination.
Topics: Adaptive Immunity; Animals; Antibody Formation; Antigens; B-Lymphocytes; CHO Cells; Cell Line; Cricetulus; Female; Germinal Center; Humans; Immunologic Memory; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Models, Animal
PubMed: 31866068
DOI: 10.1016/j.cell.2019.11.032 -
The AAPS Journal Jul 2014Immunogenicity is a significant concern for biologic drugs as it can affect both safety and efficacy. To date, the descriptions of product immunogenicity have varied not...
Immunogenicity is a significant concern for biologic drugs as it can affect both safety and efficacy. To date, the descriptions of product immunogenicity have varied not only due to different degrees of understanding of product immunogenicity at the time of licensing but also due to an evolving lexicon that has generated some confusion in the field. In recent years, there has been growing consensus regarding the data needed to assess product immunogenicity. Harmonization of the strategy for the elucidation of product immunogenicity by drug developers, as well as the use of defined common terminology, can benefit medical practitioners, health regulatory agencies, and ultimately the patients. Clearly, understanding the incidence, kinetics and magnitude of anti-drug antibody (ADA), its neutralizing ability, cross-reactivity with endogenous molecules or other marketed biologic drugs, and related clinical impact may enhance clinical management of patients treated with biologic drugs. To that end, the authors present terms and definitions for describing and analyzing clinical immunogenicity data and suggest approaches to data presentation, emphasizing associations of ADA development with pharmacokinetics, efficacy, and safety that are necessary to assess the clinical relevance of immunogenicity.
Topics: Antibody Formation; Guidelines as Topic; Humans; Peptides; Proteins; Terminology as Topic
PubMed: 24764037
DOI: 10.1208/s12248-014-9599-2 -
Immunological Reviews Sep 2021Antibody-secreting plasma cells are a central component of short- and long-term adaptive immunity. Yet, many fundamental questions about how activated B cells decide to... (Review)
Review
Antibody-secreting plasma cells are a central component of short- and long-term adaptive immunity. Yet, many fundamental questions about how activated B cells decide to yield functional plasma cells have yet to be answered. Likewise, the biochemical processes underpinning the ability of plasma cells to generate and secrete large numbers of antibodies, the capacity of some plasma cell to sustain antibody secretion, presumably without interruption, for decades, and the capacity of long-lived plasma cells to avoid apoptosis despite the high-energy demands associated with sustained robust antibody synthesis and secretion each remain mysterious processes. Our objective here is to review what is currently known about these processes with an emphasis on the earliest phases of plasma cell genesis. Along the way, we will work toward developing a model that ties the biochemistry of plasma cell function and survival. The chief idea imbedded in this model is that progress toward understanding plasma cell survival mechanisms may require increased focus on the unique cell autonomous processes inherent in plasma cell differentiation and function.
Topics: Antibody Formation; Antibody-Producing Cells; B-Lymphocytes; Cell Differentiation; Lymphocyte Activation; Plasma Cells
PubMed: 34313339
DOI: 10.1111/imr.12992 -
Frontiers in Immunology 2020
Topics: Antibody Formation; B-Lymphocytes; Drug Discovery; High-Throughput Nucleotide Sequencing; Humans; Vaccines
PubMed: 32714328
DOI: 10.3389/fimmu.2020.01344