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Controlled Vaccine Delivery
Published in Emmanuel Opara, Controlled Drug Delivery Systems, 2020
The most common form of single-injection vaccines is biodegradable particles that exhibit degradation-mediated antigen release over the course of weeks or months. By delivering antigen over time, these vaccines seek to promote the formation of antigen-specific memory B cells, affinity maturation, long-lived plasma cells, and ultimately protective levels of neutralizing antibodies. More recently, the potential role of cellular immunity has also become better understood and appreciated, though current vaccines are largely considered to work by establishing humoral immunity. Lymph node-targeting nanoparticles have also been explored as an alternative delivery strategy to enhance the magnitude of the immune response via antigen persistence in an immune cell-rich environment, albeit delivering antigen over shorter time periods.14,15 In order for single-injection vaccines to be clinically and ethically viable, they must confer immunity that is noninferior to current multidose regimens. Although there has been substantial preclinical work using controlled-release vaccines, this technology has yet to be commercialized due to challenges associated with biologics. The two key challenges facing single-injection vaccines today are release kinetics and antigen stability. These challenges are a consequence of multiple factors, including the type of vaccine, formulation method, encapsulating material, adjuvant load, and stabilizing excipients, which together determine the success of a controlled-release vaccine.
Immune Reconstitution after Hematopoietic Stem Cell Transplantation
Published in Richard K. Burt, Alberto M. Marmont, Stem Cell Therapy for Autoimmune Disease, 2019
Andreas Thiel, Tobias Alexander, Christian A. Schmidt, Falk Hiepe, Renate Arnold, Andreas Radbruch, Larissa Verda, Richard K. Burt
B cells undergo further affinity maturation within lymph node germinal centers by a process of somatic hypermutation (SHM), gene conversion, and class switching recombination (CSR) (Fig. 4). SHM is the term for insertion of point mutations in the vicinity of the variable region exon (Fig. 4) and results in generation of antigen specific high affinity antibodies. Gene conversion is the transfer of a pseudovariable (ipV)gene sequence into the variable region exon (Fig. 4). Both SHM and gene conversion alters the antigen binding site of the immunoglobulin.71-72 CSR involves switching the constant region heavy change (e.g., IgM to IgG) that alters the effector function of the antibody (Fig. 4). The mechanisms involved in DNA SHM, gene conversion, and CSR although incompletely understood probably involve common mechanisms of DNA recognition, targeting, cleavage, and repair.73 The enzyme activation-induced cytidine deaminase (AID) is involved in all three reactions by helping to create the DNA cut or cleavage.65,74-75
Wind farm layout optimization for minimum levelized cost of energy considering land lease cost, noise emission, and wake loss
Published in Rodolfo Dufo-López, Jaroslaw Krzywanski, Jai Singh, Emerging Developments in the Power and Energy Industry, 2019
Shuwei Miao, Han Li, Dan Li, Yuanhang Zhang, Baohua Yang
This section gives a detailed description of the immune clone algorithm (ICA) used in the proposed wind farm layout optimization. ICA simulates a learning technique inspired by the human immune system (Nicosia et al. 2004). It considers the optimization problem, solution, and solution quality as the antigen, antibody, and affinity, respectively. The clonal expansion and the affinity maturation are used to generate an optimal antibody (solution) that shows best affinity to the antigen (optimization problem). The unconstrained optimization problem formulated in Equation (18) refers to search the optimal WTG location xyWTG in the continuous solution space. To facilitate the description of the immune clone algorithm for the proposed WFLO, the following definitions are given.
Optimising workforce efficiency in healthcare during the COVID-19: a computational study of vehicle routeing method for homebound vaccination
Published in Production Planning & Control, 2022
Giustina Secundo, Francesco Nucci, Riad Shams, Francesco Albergo
Briefly, AIA is founded on the behaviour of the animal immune system that defends from external germs. The immune system is an adaptive pattern recognition mechanism that guards against foreign viruses and bacteria. The cells of the immune system, called antibodies, are casually spread throughout the human body. The immune system reacts to pathogens and expands the process of identifying and removing pathogens using two mechanisms: clonal selection and affinity maturation. When a disease agent strikes an organism, clonal selection produces a number of immune cells that detect and eliminate the pathogen. As cell reproduction proceeds, cells experience fast mutations, along with a selection procedure. Cells that have an excellent affinity for the pathogen propagate into memory cells.