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Basic Chemical Hazards to Human Health and Safety — II
Published in Jack Daugherty, Assessment of Chemical Exposures, 2020
Antigens are substances that activate specific defenses. Antigens are large molecules of protein, or a protein component called glycoprotein or lipoprotein, whole cells, or viruses containing proteins. One of these proteins produced by a specific immune response is called an antibody for that response, and antibodies may or may not stimulate production of additional antibodies. Antigens called haptens are incomplete antibodies that have only one antigenic determinant site and cannot stimulate a complete immune response, unless they bind with molecules that have second antigenic determinant sites. Activated lymphocytes mount a direct attack on the antigens. Lymphocyte-produced antibodies then attack the antigens. These attacks are called cellular immunity and humoral immunity respectively.
Medical Biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
One possible treatment for cancer involves MABs that bind only to cancer-cell-specific antigens and induce an immunological response against the target cancer cells. Such MABs could also be modified for delivery of a toxin, radioisotope, cytokine, or other active conjugate. It is also possible to design bispecific antibodies that can bind with their fragment antigen-binding (Fab) regions, both to target antigens and to a conjugate or effector cell. In fact, every intact antibody can bind to cell receptors or other proteins with its fragment crystallizable (Fc) region. Antibody-directed enzyme pro-drug therapy (ADEPT) is a new type of cancer treatment that uses MABs. Now, ADEPT is being used only in clinical trials. The trials aim to find out whether ADEPT may be useful as a new type of treatment for bowel cancer. ADEPT is a type of targeted therapy. It uses a MAB to carry an enzyme directly to the cancer cells. Enzymes are proteins that control chemical reactions in the body. First, the MAB is given (with the enzyme attached). A few hours later, a second drug (the pro-drug) is given. When the pro-drug encounters the enzyme, a reaction takes place. This reaction activates the pro-drug and it is then able to destroy the cancer cells. As the enzyme does not attach to normal cells, this treatment does not affect them.
Biosensing Fundamentals
Published in Simona Badilescu, Muthukumaran Packirisamy, BioMEMS, 2016
Simona Badilescu, Muthukumaran Packirisamy
Generally, monoclonal antibodies are used because they bind to one site of a particular molecule, providing a more specific test. Immunoassays detect the formation of antibody-antigen complexes through an indicator reaction. An antigen is a substance that prompts the generation of antibodies and causes an immune response. Immunoassay takes advantage of the ability of antibodies to bind selectively to the specific physical structure of the target analyte present in a sample. Working like a key and lock, the binding sites on an antibody attach noncovalently to their corresponding target analyte, also known as the antigen. Because the binding is based on the antigen’s physical shape rather than its chemical properties, antibodies do not respond to substances that have dissimilar structures. Compound-specific immunoassay kits have been developed to detect only the target analyte and its metabolites. In the environmental field, class-specific kits have demonstrated the most use. Immunoassay is the method of choice for measuring analytes normally present at very low concentrations (in the range of pM) that cannot be determined accurately by any other test.
Principles of risk decision-making
Published in Journal of Toxicology and Environmental Health, Part B, 2022
Daniel Krewski, Patrick Saunders-Hastings, Patricia Larkin, Margit Westphal, Michael G. Tyshenko, William Leiss, Maurice Dusseault, Michael Jerrett, Doug Coyle
A global infectious disease outbreak, such as the recent COVID-19 pandemic caused by the SARS-CoV-2 virus, may exert enormous public health impact: as of this writing, the World Health Organization (2022) estimates there have been over 545 million cases of COVID-19, and over 6 million deaths worldwide. Such outbreaks emerged as a result of an antigenic shift, wherein genetic components of viruses re-assort to produce a novel viral strain to which humans possess no appreciable immunity (Zambon 1999). If the disease can be transmitted easily between humans and manifest in diseases, a global pandemic may thus occur. Over the past one hundred years, the combined global burden of the 1918 Spanish flu, 1957 Asian flu, 1968 Hong Kong flu, and 2009 swine flu has amounted to tens of millions of infections, hospitalizations, and deaths, as well as billions of dollars in associated health and socioeconomic costs (Saunders-Hastings and Krewski 2016).
Immunotherapy approach with recombinant survivin adjuvanted with alum and MIP suppresses tumor growth in murine model of breast cancer
Published in Preparative Biochemistry and Biotechnology, 2018
Himani Garg, Jagdish C. Gupta, G. P. Talwar, Shweta Dubey
Tumor antigens alone are not sufficient to induce a tumor-protective response. Appropriate combination of tumor antigen and immunomodulator is crucial for success of almost all cancer immunotherapeutic approaches. Various immunomodulators such as TLR agonists, anti-CD40 antibodies, cytokines like IL-2 and IFN-á or growth factors such as GM-CSF have been investigated,[12] however, they have not shown efficacy in inducing desired antitumor immune response and clinical benefit. Bacterial molecules are another important class of immunomodulators for vaccines. Mycobacterium indicus pranii (MIP) is a nonpathogenic, mycobacterial species; developed for treatment of multibacillary lepromatous leprosy patients and was found to be an effective immunomodulator.[13]
Cell membrane-cloaked bioinspired nanoparticles: a novel strategy for breast cancer therapy
Published in Journal of Dispersion Science and Technology, 2023
Anuja Muley, Abhijeet Kulkarni, Prajakta Mahale, Vishal Gulecha
Cancer immunotherapy utilizes homotypic cell antigens as one of its approaches. Breast cancer cells have certain proteins specifically expressed on the membrane surface. They will act as antigen in the body against breast cancer. Thus, breast cancer cell membrane coated nanoparticles prove better target for nanovaccine. 4T1 cancer cell membrane coated PLGA nanoparticles loaded with imiquimod (R@837) investigated as an immune response modifier. 4T1 cancer cell membrane acts as antigenic agent to generate anti-tumor immunity. Additionally, tumor microenvironment was modified to support the biomimetic nanovaccine. The resultant biomimetic nanovaccine was found to generate long anti-tumor immunity against breast cancer and enhanced uptake in bone marrow derived stem cell [101].