In immunology, an antigen (Ag) is a molecule, moiety, foreign particulate matter, or an allergen, such as pollen, that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response.
An HIV vaccine is a potential vaccine that could be either a preventive vaccine or a therapeutic vaccine, which means it would either protect individuals from being infected with HIV or treat HIV-infected individuals.
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.
Original antigenic sin, also known as antigenic imprinting, the Hoskins effect, immunological imprinting, or primary addiction is the propensity of the immune system to preferentially use immunological memory based on a previous infection when a second slightly different version of that foreign pathogen is encountered. This leaves the immune system "trapped" by the first response it has made to each antigen, and unable to mount potentially more effective responses during subsequent infections. Antibodies or T-cells induced during infections with the first variant of the pathogen are subject to repertoire freeze, a form of original antigenic sin.
In immunology, epitope mapping is the process of experimentally identifying the binding site, or epitope, of an antibody on its target antigen. Identification and characterization of antibody binding sites aid in the discovery and development of new therapeutics, vaccines, and diagnostics. Epitope characterization can also help elucidate the binding mechanism of an antibody and can strengthen intellectual property (patent) protection. Experimental epitope mapping data can be incorporated into robust algorithms to facilitate in silico prediction of B-cell epitopes based on sequence and/or structural data.
In immunology, a linear epitope is an epitope—a binding site on an antigen—that is recognized by antibodies by its linear sequence of amino acids. In contrast, most antibodies recognize a conformational epitope that has a specific three-dimensional shape.
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:
A breakthrough infection is a case of illness in which a vaccinated individual becomes infected with the illness, because the vaccine has failed to provide complete immunity against the pathogen. Breakthrough infections have been identified in individuals immunized against a variety of diseases including mumps, varicella (Chickenpox), influenza, and COVID-19. The characteristics of the breakthrough infection are dependent on the virus itself. Often, infection of the vaccinated individual results in milder symptoms and shorter duration than if the infection were contracted naturally.
Preston "Pete" Wayne Estep III is an American biologist and science and technology advocate. He is a graduate of Cornell University, where he did neuroscience research, and he earned a Ph.D. in Genetics from Harvard University. He did his doctoral research in the laboratory of genomics pioneer Professor George M. Church at Harvard Medical School.
A subunit vaccine is a vaccine that contains purified parts of the pathogen that are antigenic, or necessary to elicit a protective immune response. Subunit vaccine can be made from dissembled viral particles in cell culture or recombinant DNA expression, in which case it is a recombinant subunit vaccine.
Peptide-based synthetic vaccines are subunit vaccines made from peptides. The peptides mimic the epitopes of the antigen that triggers direct or potent immune responses. Peptide vaccines can not only induce protection against infectious pathogens and non-infectious diseases but also be utilized as therapeutic cancer vaccines, where peptides from tumor-associated antigens are used to induce an effective anti-tumor T-cell response.
Immunomics is the study of immune system regulation and response to pathogens using genome-wide approaches. With the rise of genomic and proteomic technologies, scientists have been able to visualize biological networks and infer interrelationships between genes and/or proteins; recently, these technologies have been used to help better understand how the immune system functions and how it is regulated. Two thirds of the genome is active in one or more immune cell types and less than 1% of genes are uniquely expressed in a given type of cell. Therefore, it is critical that the expression patterns of these immune cell types be deciphered in the context of a network, and not as an individual, so that their roles be correctly characterized and related to one another. Defects of the immune system such as autoimmune diseases, immunodeficiency, and malignancies can benefit from genomic insights on pathological processes. For example, analyzing the systematic variation of gene expression can relate these patterns with specific diseases and gene networks important for immune functions.
Immunodominance is the immunological phenomenon in which immune responses are mounted against only a few of the antigenic peptides out of the many produced. That is, despite multiple allelic variations of MHC molecules and multiple peptides presented on antigen presenting cells, the immune response is skewed to only specific combinations of the two. Immunodominance is evident for both antibody-mediated immunity and cell-mediated immunity. Epitopes that are not targeted or targeted to a lower degree during an immune response are known as subdominant epitopes. The impact of immunodominance is immunodomination, where immunodominant epitopes will curtail immune responses against non-dominant epitopes. Antigen-presenting cells such as dendritic cells, can have up to six different types of MHC molecules for antigen presentation. There is a potential for generation of hundreds to thousands of different peptides from the proteins of pathogens. Yet, the effector cell population that is reactive against the pathogen is dominated by cells that recognize only a certain class of MHC bound to only certain pathogen-derived peptides presented by that MHC class. Antigens from a particular pathogen can be of variable immunogenicity, with the antigen that stimulates the strongest response being the immunodominant one. The different levels of immunogenicity amongst antigens forms what is known as dominance hierarchy.
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.
EpiVacCorona is a peptide-based vaccine against COVID-19 developed by the Russian VECTOR Center of Virology. The lack of protective effectiveness of EpiVacCorona, which is still in use in Russia, has been reported in scientific literature and in the media. The vaccine consists of three chemically synthesized peptides that are conjugated to a large carrier protein. This protein is a fusion product of a viral nucleocapsid protein and a bacterial MBP protein. A phase III clinical trial to show whether or not the vaccine can protect people against COVID-19 was launched in November 2020 with more than three thousand participants. The conclusions and results of the trial have not been made public.
UB-612 is a COVID-19 vaccine candidate developed by United Biomedical Asia, and Vaxxinity, Inc. It is a peptide vaccine.
Spike (S) glycoprotein is the largest of the four major structural proteins found in coronaviruses. The spike protein assembles into trimers that form large structures, called spikes or peplomers, that project from the surface of the virion. The distinctive appearance of these spikes when visualized using negative stain transmission electron microscopy, "recalling the solar corona", gives the virus family its main name.
A universal coronavirus vaccine, also known as a pan-coronavirus vaccine, is a theoretical coronavirus vaccine that would be effective against all coronavirus strains. A universal vaccine would provide protection against coronavirus strains that have caused disease in humans, such as SARS-CoV-2, while also providing protection against future coronavirus strains. Such a vaccine has been proposed to prevent or mitigate future coronavirus epidemics and pandemics.
COH04S1 is a covid vaccine developed by the City of Hope Medical Center. This vaccine targets patients who are immunocompromised; immunocompromised patients have often shown a weak antibody response to past COVID-19 vaccines. COH04S1 is also targeted on people who are at a high risk of COVID-19 complications. The City of Hope Medical Center strives to make a better option than the current EUA and FDA approved vaccines, which are not working as well on this group of individuals.
Christopher O. Barnes is an American chemist who is an assistant professor at Stanford University. During the COVID-19 pandemic, he studied the structure of the coronavirus spike protein and the antibodies that attack them. He was named one of ten "Scientists to watch" by Science News in 2022.
