Biologic Drug Substance and Drug Product Manufacture
Anthony J. Hickey, Sandro R.P. da Rocha in Pharmaceutical Inhalation Aerosol Technology, 2019
In the body, an antibody is a protein produced by β-lymphocytes in response to substances recognized as foreign (“antigens”). Antibodies recognize and bind to antigens, resulting in their inactivation or opsonization (binding of antibody to the membrane surface of invading pathogen, thus marking it for phagocytosis) or complement-mediated destruction. Antibodies are also known as immunoglobulins (abbreviated Ig) since they are immune-response proteins that are globular proteins (compact with higher orders of structure and hydrophilic surface making them soluble; as opposed to fibrous proteins, which have predominantly secondary structure and are insoluble). Of the five major types of antibodies (Table 8.1), immunoglobulin G (IgG) is preferred for therapeutic applications due to its wide distribution and function.
Antiviral Agents and Rational Drug Design
Nathan Keighley in Miraculous Medicines and the Chemistry of Drug Design, 2020
Immune responses can be broadly classified as either antibody responses, or cell-mediated immune responses. Antibody responses involve the production of antibodies by certain cells known as B cells, which circulate the blood steam and permeate other body fluids in search of the antigens that induced their creation. Antibodies are proteins known as immunoglobulins and they bind to this specific antigen, which inactivates its toxic effects by subverting the toxin’s binding to cell receptors. Antibody binding to antigens on the cell surface of a pathogen marker the invading microorganism, making it readily identifiable by phagocytes; cells of the immune system that engulf and destroy the invader. Specialised cells, called T cells, that target the foreign invader, produced during cell-mediated immune responses, react with the antigens on the surface of infected host cells. The T cells may kill the virus-infected host cell, thus eliminating it before the virus has replicated, or in other cases the T cells may produce chemical messages to activate macrophages to destroy the invading virus.
Vaccine Adjuvants in Immunotoxicology
Mesut Karahan in Synthetic Peptide Vaccine Models, 2021
Passive immunity is the immunity transmitted from one source to another (e.g. mother to baby). Passive immunity provides short-term protection expressed in weeks or months (Baxter 2007). The humoral or antibody-mediated immunity depends on the presence of antibodies in the blood and body fluids. The combination of an antigen with an antibody creates many responses. During the development of humoral immunity, the primary immune response occurs when the antigen enters the body for the first time (Zeitlin et al. 2000). Secondary or memory response is created in the second or subsequent encounters with the antigen. During the secondary response, the increase in the level of antibodies occurs in a shorter time and reaches a higher level due to the pre-existing memory cells (Beyaz 2004). The effect of T lymphocytes and macrophages is dominant in cellular immunity (Hanna et al. 2004). There are four main stages in the creation of the immune response: firstly the recognition of an antigen and the activation of the antigen-presenting cells, secondly the presentation of the antigen to T lymphocytes produced by the antigen-presenting cells, thirdly the formation of the co-stimulatory molecules, and the secretion of cytokines is the last step (Songu and Katılmış 2012).
Molecular Diagnostic Tools for the Detection of SARS-CoV-2
Published in International Reviews of Immunology, 2021
Manali Datta, Desh Deepak Singh, Afsar R. Naqvi
The presence of antibody indicates that an immune response has developed in the person exposed to the pathogen. Serology testing is recommended only for observational purposes and not for diagnostics. However, the information on the intensity of adaptive immune response activation can provide insights into an individual’s ability to restrict virus and may be critical in understanding virus pathobiology. Serologic assays are important in cases where RNA may be difficult to isolate or is no longer present, and for epidemiological studies [27]. Sensitivity may be categorized as analytical and diagnostic. Analytical sensitivity is defined as the ability of a test to analyze antigen or antibody concentration in a target biological sample, whereas diagnostic sensitivity is a test’s sensitivity with true positive rate against incidence of disease. Accuracy, an indispensable term in diagnostic development, is defined as the number of true positives and true negatives in targeted sampling [27,35,36].
Monoclonal antibodies for the management of central nervous system diseases: clinical success and future strategies
Published in Expert Opinion on Biological Therapy, 2023
Avtar Singh Gautam, Shivam Kumar Pandey, Vaibhav Lasure, Sachin Dubey, Rakesh Kumar Singh
Although mAbs are effective modern therapeutics, they carry a risk of potential adverse effects also. mAbs can trigger a diverse range of adverse effects like immunological reactions, infections, hemorrhage, edema and malignancies. Antibody is made up of different parts, one of which could be recognized as foreign that may trigger the initiation of a set of immunological reactions including anaphylactic reactions initiated by IgE, cytokine release syndrome and serum sickness syndrome. The clinical manifestation triggered by mAbs can range from local skin reaction at the injection site, pyrexia, and influenza to anaphylaxis and systemic inflammatory response that could be fetal in nature. The mAbs can induce autoimmune disease, due to their immunomodulatory activity such as immunosuppression. The mAbs are also responsible for organ toxicity, like cardiotoxicity as induced by trastuzumab. Bevacizumab, a humanized mAbs against VEGF, is reported to cause arterial and venous thromboembolic events in patients. Cetuximab, a chimeric EGFR specific mAbs has been reported to induce production of IgE antibodies against galactose-α-1,3-galactose.
An overview of in silico vaccine design against different pathogens and cancer
Published in Expert Review of Vaccines, 2020
Kimia Kardani, Azam Bolhassani, Ali Namvar
The development of a strong and effective antibody response is more complicated to treat and prevent infections and tumors. The inability of synthetic linear peptides to effectively mimic the discontinuous epitopes is one of the reasons for the failure of many B cell synthetic vaccines. These results illustrate why more than a thousand synthetic B cell peptides have been determined, but only 125 and 30 of them have achieved to phases I and II trials, respectively. Moreover, none of them have achieved success in phase III or licensed for human use [53]. Generally, the lack of clinical efficacy of some epitope-based vaccines against different pathogens may happen due to these reasons including (A) the restricted conserved sequence, (B) the limited number of epitopes, (C) the restricted population coverage of HLA, (D) insignificant delivery, and (E) existence of the epitopes which stimulate regulatory T cell responses [54]. Thus, in order to develop strong and potent epitope-based vaccines, scientists must try to eliminate and solve the problems mentioned earlier. For example, the number of epitopes needed for complete protection was known as a definable and small subset (lower than 50) [55,56]. In this review, we will briefly describe immuno-informatics approaches to design an efficient multiepitope vaccine candidate in preclinical and clinical trials performed up to now. Figure 1 illustrates the total steps of designing and prediction of an efficient multiepitope-based vaccine.
Related Knowledge Centers
- Immunoglobulin A
- Immunoglobulin D
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- Protein
- Epitope
- Immune System
- Pathogenic Bacteria
- Viral Disease
- Antigen