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Vaccine Adjuvants in Immunotoxicology
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
Saponins are steroid or triterpenoid-form glycosides found in wild and cultivated plants, some primitive sea creatures, and bacteria. Saponins contain a steroidal or triterpenoid aglycon to which one or more sugar chains are bound (Sun, Xie, and Ye 2009). Saponins are extraordinary candidates for the development of a new adjuvant. It was found that many saponins had adjuvant effects on purified protein antigens (Song and Hu 2009). Their stimulation of the immune system in mammals has increased their use as a vaccine adjuvant. Saponin-based adjuvants modulate the cellular immune system, increase antibody production, and can be used at low doses for their efficacy. They have complex action pathways such as stimulating T-dependent antigens, inducing CD8+ and enhancing the response to mucosal antigens (Gül and Dikmen-Yurdakök 2019). Saponins are generally safe; however, the safety changes depending on the route of administration, animal species, and some specific saponins. In addition, intravenous (IV) injections of saponins may cause toxicity due to hemolysis (Gül and Dikmen-Yurdakök 2019).
Interleukin 12: A Potent Vaccine Adjuvant for Promoting Cellular Immunity and Modulating Humoral Immunity
Published in Thomas F. Kresina, Immune Modulating Agents, 2020
Overall, the studies summarized argue strongly that IL-12 is a potent vaccine adjuvant with potential in many therapeutic and prophylactic indications. Its ability to enhance cellular immunity to specific tumor antigens (both described and yet to be identified) and demonstrated efficacy in therapeutic antitumor models suggest that prudent and creative extension to the clinical setting holds great promise. In addition the sustained memory response for antigen-specific IFN-γ production offers opportunities for prophylactic immunization against many parasitic diseases. Finally, the observation that IL-12 shifts the humoral response to expression of antibody subclasses which fix complement and the finding that it also increases antibody titers offers the potential for IL-12 as a prophylactic vaccine in many viral and other infectious diseases.
Influenza
Published in Firza Alexander Gronthoud, Practical Clinical Microbiology and Infectious Diseases, 2020
Vaccination remains the cornerstone of prevention and control of seasonal epidemics. There are three types of influenza vaccines available: a live, attenuated influenza vaccine (LAIV), an inactivated influenza vaccine (IIV) and a recombinant HA vaccine. The main shortcoming of influenza vaccines is that annual updates are needed to retain effectiveness because of antigenic shift occurring. It takes about 14 days for the vaccine to become protective, with a vaccine effectiveness generally ranging between 40% and 70%. Furthermore, the vaccine is less effective in the elderly, requiring a vaccine adjuvant or a higher dose potentially. Recently, a vaccine for avian influenza H5N1 has been developed.
Targeting toll-like receptor 4 to modulate neuroinflammation in central nervous system disorders
Published in Expert Opinion on Therapeutic Targets, 2019
Gunnar R. Leitner, Tyler J. Wenzel, Nick Marshall, Ellen J. Gates, Andis Klegeris
Agonists of TLR 4 may offer an alternative avenue for targeting some of the pathophysiological mechanisms associated with certain neurodegenerative conditions. For instance, observations that E6020, a vaccine adjuvant, promotes myelin regeneration in the spinal cords of MS model rats provide evidence that this drug could be beneficial in MS [74]. MPL, another vaccine adjuvant, could potentially be developed as a therapeutic agent for AD, as it has been shown to prevent the accumulation of Aβ in AD mice models [138]. Since TLR 4 activation would be expected to upregulate neuroinflammation and promote glial scarring [64], further careful preclinical and clinical safety studies will be required before these drugs could be recommended for clinical trials with patients suffering from neurodegenerative and other CNS diseases. Design and optimization of agonists selectively targeting the TLR 4 MyD88-independent signaling pathway could be a possible future drug development strategy since such agonists may preferentially enhance beneficial phagocytosis while only moderately upregulating proinflammatory mediators in both the periphery and the CNS [126,136].
Current research into novel therapeutic vaccines against cervical cancer
Published in Expert Review of Anticancer Therapy, 2018
Marcelo Nazário Cordeiro, Rita de Cássia Pereira De Lima, Francesca Paolini, Alanne Rayssa da Silva Melo, Ana Paula Ferreira Campos, Aldo Venuti, Antonio Carlos De Freitas
Adjuvants are essential elements to achieve full effectiveness of a vaccine, or at least, acceptable employability in genetic or peptide immunization. The vaccine adjuvant is part of the vaccine composition that potentiates immune response to the antigen and/or modulates it toward the desired immune responses, without specific protective effect itself. Such molecules are especially relevant for genetic immunization strategy since antigen-coding DNA has a very low immunogenicity in superior primates and humans [91]. Thus, adjuvants should promote a local pro-inflammatory environment that assures immune response development by properly lymphocytes signaling, migration, maturing and surviving. Several adjuvants have been tested in order to promote increased and/or long-term immune response in vaccine co-administration protocols. Each approach bears advantages and limitations that must be considered in their respective ways of action and purposes together with the chosen antigen. Novel adjuvants have arisen from previously known molecules with some role in immune response development, such as Toll-like receptors (TLR) agonists, granulocyte-macrophage colony-stimulating factor (GM – CSF), ubiquitin-like proteins, interleukins and others.
Combined adjuvant-delivery system for new generation vaccine antigens: alliance has its own advantage
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Monika Kaurav, Jitender Madan, M. S. Sudheesh, Ravi Shankar Pandey
Vaccine delivery systems and their adjuvants work via a variety of ways in patient’s immune system. Thus, several characteristics should be considered in the selection of an ideal vaccine adjuvant for all type of vaccines. A vaccine adjuvant must be appropriate in all desire aspects such as physical, biological, histopathological and economical, etc. Physical characteristics: it should be in a state, which is compatible to formulate with vaccine delivery system and easy to given by particular delivery routes (e.g. intraperitoneal, intramuscular, mucosal, nasal, etc.) [15]. Biological and histopathological characteristics: it must be able to provide a desired immune response that further depends on the pathogen, medical history, age, race and genetic structure of the patient. Economic considerations must also be taken into account during selection process such as low cost with ease manufacture, good stability profile, less toxic with minimum inflammation and provide protective immunity in low dose manner. Risk/profit analysis for the adjuvanted vaccine ought to be favourable. Despite the safety information, evaluation of risk associated with licensure vaccine vaccination is also a necessary task. Several licensure vaccines have been withdrawn from the market due to adverse events appearance in recipients or due to poor efficacy of the vaccines. So, the evaluation of side effects associated with adjuvants should be necessary along with its immunogenicity enhancement ability. The adverse effects occur such as the rare formation of sterile abscess or granuloma, arthritis, fever, and uveitis may be due to adjuvant-antigen interaction [16].