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The Inducible Defense System: Antibody Molecules and Antigen-Antibody Reactions
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Biological assays: The presence of antibody can be detected using a variety of biological assay systems. In most cases, such tests utilize the basic principles described above. For example, antibody may bind to viruses and prevent them from entering cells. Such antibody is often called neutralizing antibody. Ln a viral neutralization assay, viruses are combined with dilutions of the serum being tested, and then the mixtures are added to a tissue culture flask containing a monolayer of cells. If antibodies are present, the virus will be neutralized; if antibodies are not present, the virus will invade the cells and cause cytopathic alterations of the cells that are then observed microscopically. A variety of inhibition of invasion or inhibition of growth assays are available for measuring antibody responses to different pathogens.
Lessons Learned from COVID-19 and Their Implementations for Future Pandemics
Published in Debmalya Barh, Kenneth Lundstrom, COVID-19, 2022
Mauricio Corredor, Debmalya Barh, Kenneth Lundstrom
A search using “immunology” and “COVID-19” in Google Scholar, found 2.310.000 hits. SARS-CoV-2 infections elicit multiple antibody responses with neutralizing activity, demonstrated in animal models and human clinical trials [64]. These responses allow the identification of SARS-CoV-2 in infected, re-infected, or future patients. Today, viral immunology is useful to diagnose and determine the viral charge, allowing the development of immunological tests. The most relevant achievement in COVID-19 immunology so far, of course, has been the successful development of several vaccines [65]. The discovery of neutralizing antibody responses to SARS-CoV-2 in recovered COVID-19 patients, and their implications, are also important immunological findings [66].
Historical perspectives of allergen immunotherapy
Published in Richard F. Lockey, Dennis K. Ledford, Allergens and Allergen Immunotherapy, 2020
David Fitzhugh, Sheldon G. Cohen, Richard Evans
During the late 1930s, allergen vaccines were modified in an effort to decrease the frequency of injections. Depot-like immunogenic materials were prepared to provide a slow, continuous release of allergen from injection sites. The first attempt used ground raw pollen suspended in olive oil [107]. Because particulate bacterial vaccines and modified toxoid proved to be effective immunogens, soluble pollen allergen vaccines were converted to particulate suspensions by alum precipitation and alum adsorption [108,109]. Other modifications included acetylation, heat, and formalin treatment [109]; precipitation by tannic [110] and hydrochloric acids [111]; and a mixture with gelatin [112]. Of these, only alum-adsorbed pollen extracts gained any popularity. Treatment of hay fever with an emulsified allergen vaccine was introduced by Naterman, who in 1937 emulsified a pollen extract with lanolin and olive oil [113]. Thirteen years later, he suspended grass and ragweed pollen tannate in peanut oil with aluminum monostearate [114]. Malkiel and Feinberg, encouraged by evidence of slow absorption from new penicillin-in-oil depot formulations, prepared extracts of ragweed in sesame oil–aluminum monostearate. With these, however, they were unable to avoid constitutional reactions, while failing to reduce the severity of symptoms [115]. Furthermore, other investigators detected increased titers of neutralizing antibody in treated patients without clinical benefit, thus casting doubt on the clinical relevance of “blocking” antibody [116,117].
Diverse vaccine platforms safeguarding against SARS-CoV-2 and its variants
Published in Expert Review of Vaccines, 2022
Bhaswati Chatterjee, Suman S. Thakur
4.1.1. ChAdOx1 nCoV-19/Covishield: Folegattiet et al from the University of Oxford/AstraZeneca, have selected 1077 healthy participants in the age group of 18 to 55 years and administered 5 × 1010 viral particles of chimpanzee adenovirus-vectored vaccine (ChAdOx1 nCoV-19) [42]. This vaccine expresses SARS-CoV-2 spike proteins in 543 participants. Further, the meningococcal conjugate vaccine (MenACWY) was used as a control in 534 participants. Notably, there were no adverse side effects, while common symptoms have been minimized by paracetamol. Significantly, spike-specific T-cell responses peaked on day 14 and Anti-spike IgG responses rose by day 28 and further the booster dose was given. Neutralizing antibody response was detected in more than 90% of participants after the first dose while it was detected in 100% of participants after the second dose [42]. The vaccine did not have any adverse side effects. Furthermore, this study may be extended to patients with chronic diseases, old age, neonatal and pediatrics thereby giving protection from SARS-CoV-2 infection and recovered SARS-CoV-2 individuals from re-infection. Notably, the efficacy of this vaccine should be tested against different recent circulating strains of SARS-CoV-2. Moreover, further studies are required to unearth the long duration of immunity caused by this vaccine and the requirement for booster doses in the future. The need to extend the suitability of this vaccine to different ethnic groups and persons with rare diseases such as blood clotting complications might be helpful.
Convalescent plasma and hyperimmune globulin therapy in COVID-19
Published in Expert Review of Clinical Immunology, 2021
A neutralizing antibody previously produced against an infectious agent may cross-react with other infectious agents. More than one type of neutralizing antibody against a specific microorganism may be found in both HIG and CP. To give a standard titer of a specific neutralizing antibody to a patient, a reliable antibody titration assay should be developed. For a reliable assay, the isolation of the virus is needed first. Then, the serial titers of a neutralizing antibody should be defined by evaluating the cytopathic effect with serial dilutions of the virus [22]. The neutralizing antibody test will help the clinicians to measure the titer of the antibody in CP therapies. On the other hand, this is also a requirement to produce a standard commercial HIG product having a definite titer of neutralizing antibody.
Understanding the dynamics of COVID-19; implications for therapeutic intervention, vaccine development and movement control
Published in British Journal of Biomedical Science, 2020
S Salvamani, HZ Tan, WJ Thang, HC Ter, MS Wan, B Gunasekaran, A Rhodes
Other workers have investigated the dynamics of the immune response in SARS-CoV-2-infected individuals. Seow et al. [117] conducted a longitudinal evaluation of antibody response in individuals up to 94-days post-infection, using sequential serum samples to measure titres and neutralizing antibody response in individuals with differing levels of disease and differing viral loads. The magnitude of the neutralizing response was dependent on the severity of the disease, with declining neutralizing antibody titres observed during the follow up period. Interestingly, the IgM and IgA-specific responses to the viral proteins (spike, the receptor-binding domain and nucleoproteins) rapidly declined after twenty to 30 days, compared to the longer lasting IgG response: an important consideration for testing strategies and for seroprevalence studies [117]. For individuals with low infection rates, the neutralizing antibody titres were found to be at or below the level of detection after only 50 days. This obviously has implications for vaccine development if the challenge results in a relatively transient response. Antibody responses to other human coronaviruses have been found to be similarly transient, in some cases as little as 12 weeks. However, antibodies to SARS-CoV and MERS have been detected up to 12–34 months after infection [118,119].