![]() ![]() It involves the activation of allergen-specific B cells and the production of IgE antibodies (Fig. Further, the MHC-II–epitope complex was identified by the T helper cell receptor, which can raise the alarm and trigger the T helper cells-mediated immune response to release interleukins. The APC present these spike protein fragments (epitopes) through MHC-II molecules on its surface. From the immunological point of view, after vaccination, these mRNA vaccines enter into the human cells and are translated into protein fragments (especially spike glycoprotein), which they present to the surface and are recognized by the human immune cells (e.g., APC-antigen-presenting cells). Then, the IgE–allergen complex that binds with the receptor on mast cells or basophils causes allergic reactions such as the release of histamine, prostaglandins, and leukotrienes, proteases. The linear epitopes are formed by the three-dimensional conformation adopted by the IgE paratope interaction of contiguous amino acid residues. This epitope may be a linear (stable) or conformational (less stable) epitope. To provoke sustained immune response, the immunological (glycoprotein) molecule that binds specifically with the membrane receptor (i.e., antibody IgE) on T or B cell is known as an epitope. Glycoprotein-induced anaphylaxis: Many food allergens include egg, fish, milk, shellfish, and tree nuts that contain water-soluble glycoproteins, which are relatively stable to heat, acid, and proteolytic action. ![]() ![]() Thus, the National center for immunization and respiratory diseases (NCIRD), Centers for disease control and prevention (CDC) advised health authorities of all countries to exclude anyone with a history of a severe allergic reaction associated with one of the vaccine components, especially PEG and PEG derivatives like polysorbates. ![]() In addition, Castells and Phillips noted that severe anaphylaxis reaction was observed in health care workers within 24 h after vaccination in the United Kingdom and Boston, United States. reported severe allergic reactions in some people who received the BNT162b2, and fewer people who received the mRNA-1273 vaccine. Moreover, the clinical trials of the BNT162b2 vaccine were conducted with a random selection of participants. The demographic and clinical characteristics of the mRNA-1273 vaccine included participants (0.6–4.9%) having a history of chronic lung disease, cardiac disease, severe obesity, diabetes, liver disease, and human immunodeficiency virus infection. Both candidate vaccines use PEGlyated lipid nanoparticles as a carrier for vaccine delivery, which is administered through intramuscular injection to the patients and volunteers as well. The incidence of serious adverse effects of these mRNA vaccines was reported low but included mild-to-moderate pain at the injection site, fatigue, and headache. Vaccinated COVID-19 patients or volunteers (age > 18) with mRNA-1273 (2 × 100 μg/dose) in 28 days of interval acquired 94.1% protection ( No: NCT04470427) against SARS-CoV-2. Likewise, mRNA-1273 vaccine components include the spike glycoprotein of SARS-CoV-2 coding mRNA, PEG 2000 dimyristoyl glycerol, 1,2-distearoyl-sn-glycero-3-phosphocholine, cholesterol, SM-102, tromethamine, tromethamine hydrochloride, acetic acid, sodium acetate, and sucrose. COVID-19 patients or volunteers (age > 16) who received BNT162b2 vaccination at 21-day intervals of two dosages (30 μg/dose) attained 95% protection ( No: NCT04368728) against SARS-CoV-2. Briefly, the BNT162b2 vaccine contains the spike glycoprotein of SARS-CoV-2 coding mRNA, 2 - N, N-di-tetradecyl acetamide, 1, 2-distearoyl-sn-glycero-3-phosphocholine, cholesterol, (4-hydroxybutyl) azanediyl) bis (hexane-6, 1-diyl) bis (2-hexyldecanoate), potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dehydrate, and sucrose. In the last 2 weeks, we read about the components of these two mRNA vaccines from different media resources. ![]()
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