Alessandro Sette | |
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Born | August 11, 1960 62) Rome, Italy | (age
Alma mater | University of Rome |
Known for | Defining how T cells see antigens |
Alessandro Sette is an Italian immunologist. He was born on August 11, 1960, in Rome, Italy, to Pietro Sette, a prominent Italian businessman and politician, and Renata Sette. Sette is a professor at La Jolla Institute for Immunology (LJI). He is an adjunct professor at the University of California, San Diego. Sette studies the specific epitopes that the immune system recognizes in cancer, autoimmunity, allergy, and infectious diseases. [1]
In 1988, Sette moved to San Diego to conduct research at San Diego biotech Cytel. He then co-founded Epimmune. In 2003, Sette joined the faculty of La Jolla Institute for Immunology. [2]
Sette co-leads the Immune Epitope Database (IEDB), an NIAID-funded online database that catalogues epitopes involved in immune system recognition of allergens, infectious diseases, autoantigens, and transplanted tissue in humans and various species.
In 2020, Sette published the first study of SARS-CoV-2 epitopes targeted by the human immune system. [3] He has co-led research into CD8+ and CD4+ T cell responses in COVID-19 patients [4] and studied CD8+ T cell cross-reactivity to SARS-CoV-2 epitopes and other coronaviruses. [5]
Sette received his Laurea in Biological Sciences from the University of Rome, Italy, followed by postdoctoral fellowships in Immunology with Luciano Adorini [6] [7] at the C.R.E. Casaccia in Rome, Italy, and Howard Grey [8] [9] at the National Jewish Center for Immunology and Respiratory Medicine in Denver, Colorado.
Sette is a coauthor of over 900 peer-reviewed publications, and is an inventor on 41 US issued patents. He has a H-factor of 182, [10] and is identified by Clarivate as a highly cited researcher. [11]
In the mid-80s, at the same time as Paul Allen in Emil Unanue’s lab, Sette together with Soren Buus in Howard Grey’s lab reported the first direct evidence that MHC molecules’ function is to bind antigenic peptides [15] [16] and present them to the T cell receptor, which triggers a T cell response. Follow-up work explained MHC restriction. [17] [18] In 1989, utilizing an Apple IIe, Sette wrote the first algorithm [19] to predict peptide binding to two murine MHC alleles and over the course of the next 25 years, he defined motifs associated with over one hundred different class I and class II MHC variants expressed in humans, chimps, macaques, gorilla, horse, and mice. [20] [21] [22] He discovered and characterized how MHC variants can be grouped according to broad common functional specificities (MHC supertypes), greatly facilitating epitope classification, characterization and understanding the basic rules of epitope-MHC interactions. [23]
Contrary to the then wide-held assumption that T cell receptors (TCR) solely function as on/off switches, Sette showed that depending on the affinity of the interaction, TCR engagement could result in inhibition of T cell activation, normal activation, or heteroclitic stimulation and differential signaling, in a mechanism that is known as TCR antagonism. [24] [25] This discovery had a profound influence on the understanding of the impact of epitope analogs on antigen recognition, development of more potent cancer antigens, and basic studies on positive and negative selection. [26] [27] Sette is using epitopes as specific probes to define the understanding of immune responses to many different targets, from infectious diseases such as COVID-19, [28] [29] tuberculosis, [30] whooping cough, dengue [31] or Zika, to allergies and asthma caused by pollens, [32] cockroaches and dust mites, to vaccines, [33] autoimmunity and neurodegenerative diseases and cancer.
Sette's group was first to define successful adaptive response to SARS-CoV-2, by studying mild convalescent samples, and defined durability of immune memory in natural infection and vaccination. [34] [35] We reported the phenomenon of SARS-CoV-2 preexisting immune memory in unexposed donors, and demonstrated its influence on vaccination outcomes. [36] [37] We also demonstrated that T cell responses are largely preserved in terms of recognition of SARS-CoV-2 variants, including Omicron and Delta. [38]
In immunology, an antigen (Ag) is any molecule, molecular structure, foreign particulate matter, or pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. Antigens can be proteins, peptides, polysaccharides, lipids, or nucleic acids.
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism's own healthy tissue. Many species have two major subsystems of the immune system. The innate immune system provides a preconfigured response to broad groups of situations and stimuli. The adaptive immune system provides a tailored response to each stimulus by learning to recognize molecules it has previously encountered. Both use molecules and cells to perform their functions.
The major histocompatibility complex (MHC) is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. These cell surface proteins are called MHC molecules.
An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The part of an antibody that binds to the epitope is called a paratope. Although epitopes are usually non-self proteins, sequences derived from the host that can be recognized are also epitopes.
An antigen-presenting cell (APC) or accessory cell is a cell that displays antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs). APCs process antigens and present them to T-cells.
MHC class I molecules are one of two primary classes of major histocompatibility complex (MHC) molecules and are found on the cell surface of all nucleated cells in the bodies of vertebrates. They also occur on platelets, but not on red blood cells. Their function is to display peptide fragments of proteins from within the cell to cytotoxic T cells; this will trigger an immediate response from the immune system against a particular non-self antigen displayed with the help of an MHC class I protein. Because MHC class I molecules present peptides derived from cytosolic proteins, the pathway of MHC class I presentation is often called cytosolic or endogenous pathway.
In academia, computational immunology is a field of science that encompasses high-throughput genomic and bioinformatics approaches to immunology. The field's main aim is to convert immunological data into computational problems, solve these problems using mathematical and computational approaches and then convert these results into immunologically meaningful interpretations.
Immunogenicity is the ability of a foreign substance, such as an antigen, to provoke an immune response in the body of a human or other animal. It may be wanted or unwanted:
Antigen presentation is a vital immune process that is essential for T cell immune response triggering. Because T cells recognize only fragmented antigens displayed on cell surfaces, antigen processing must occur before the antigen fragment, now bound to the major histocompatibility complex (MHC), is transported to the surface of the cell, a process known as presentation, where it can be recognized by a T-cell receptor. If there has been an infection with viruses or bacteria, the cell will present an endogenous or exogenous peptide fragment derived from the antigen by MHC molecules. There are two types of MHC molecules which differ in the behaviour of the antigens: MHC class I molecules (MHC-I) bind peptides from the cell cytosol, while peptides generated in the endocytic vesicles after internalisation are bound to MHC class II (MHC-II). Cellular membranes separate these two cellular environments - intracellular and extracellular. Each T cell can only recognize tens to hundreds of copies of a unique sequence of a single peptide among thousands of other peptides presented on the same cell, because an MHC molecule in one cell can bind to quite a large range of peptides. Predicting which antigens will be presented to the immune system by a certain MHC/HLA type is difficult, but the technology involved is improving.
MHC Class II molecules are a class of major histocompatibility complex (MHC) molecules normally found only on professional antigen-presenting cells such as dendritic cells, mononuclear phagocytes, some endothelial cells, thymic epithelial cells, and B cells. These cells are important in initiating immune responses.
MHC-restricted antigen recognition, or MHC restriction, refers to the fact that a T cell can interact with a self-major histocompatibility complex molecule and a foreign peptide bound to it, but will only respond to the antigen when it is bound to a particular MHC molecule.
In immunology, peripheral tolerance is the second branch of immunological tolerance, after central tolerance. It takes place in the immune periphery. Its main purpose is to ensure that self-reactive T and B cells which escaped central tolerance do not cause autoimmune disease. Peripheral tolerance prevents immune response to harmless food antigens and allergens, too.
Human leukocyte histocompatibility complex DO (HLA-DO) is an intracellular, dimeric non-classical Major Histocompatibility Complex (MHC) class II protein composed of α- and β-subunits which interact with HLA-DM in order to fine tune immunodominant epitope selection. As a non-classical MHC class II molecule, HLA-DO is a non-polymorphic accessory protein that aids in antigenic peptide chaperoning and loading, as opposed to its classical counterparts, which are polymorphic and involved in antigen presentation. Though more remains to be elucidated about the function of HLA-DO, its unique distribution in the mammalian body—namely, the exclusive expression of HLA-DO in B cells, thymic medullary epithelial cells, and dendritic cells—indicate that it may be of physiological importance and has inspired further research. Although HLA-DM can be found without HLA-DO, HLA-DO is only found in complex with HLA-DM and exhibits instability in the absence of HLA-DM. The evolutionary conservation of both DM and DO, further denote its biological significance and potential to confer evolutionary benefits to its host.
HLA class II histocompatibility antigen gamma chain also known as HLA-DR antigens-associated invariant chain or CD74, is a protein that in humans is encoded by the CD74 gene. The invariant chain is a polypeptide which plays a critical role in antigen presentation. It is involved in the formation and transport of MHC class II peptide complexes for the generation of CD4+ T cell responses. The cell surface form of the invariant chain is known as CD74. CD74 is a cell surface receptor for the cytokine macrophage migration inhibitory factor (MIF).
La Jolla Institute for Immunology is a non-profit research organization located in La Jolla, California. It is located in UC San Diego’s Research Park. The institute researches immunology and immune system diseases. The institute employs 220 M.D.s and Ph.D.s, including 23 faculty members and more than 450 employees. Dr. Mitchell Kronenberg has served as its president and scientific director since 2003. The institute was founded in 1988.
In immunology, clonal deletion is the removal through apoptosis of B cells and T cells that have expressed receptors for self before developing into fully immunocompetent lymphocytes. This prevents recognition and destruction of self host cells, making it a type of negative selection or central tolerance. Central tolerance prevents B and T lymphocytes from reacting to self. Thus, clonal deletion can help protect individuals against autoimmunity. Clonal deletion is thought to be the most common type of negative selection. It is one method of immune tolerance.
MHC multimers are oligomeric forms of MHC molecules, designed to identify and isolate T-cells with high affinity to specific antigens amid a large group of unrelated T-cells. Multimers generally range in size from dimers to octamers; however, some companies use even higher quantities of MHC per multimer. Multimers may be used to display class 1 MHC, class 2 MHC, or nonclassical molecules from species such as monkeys, mice, and humans.
Jawless vertebrates, which today consist entirely of lampreys and hagfish, have an adaptive immune system similar to that found in jawed vertebrates. The cells of the agnathan AIS have roles roughly equivalent to those of B-cells and T-cells, with three lymphocyte lineages identified so far:
Frances Brodsky is an American cell biologist. She is known for her work on clathrin and its role in the function of the immune system. She is a professor of cell biology and the director of the Division of Biosciences at University College London. She is the author of three scientific mystery novels under the pseudonym B.B. Jordan. She was the founding editor of the journal Traffic.
Shane Patrick Crotty is a professor of immunology in the Center for Infectious Disease and Vaccine Research at La Jolla Institute for Immunology.