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An Introduction to the Immune System and Vaccines
Published in Patricia G. Melloy, Viruses and Society, 2023
Many immunologists have spent their careers trying to figure out the critical question in immunology: how the body recognizes “self” versus “nonself” (Nicholson 2016). More specifically, scientists wonder what the body is recognizing when the immune cells identify something as nonself. How does the body know a foreign invader is present? It turns out that immune cells can recognize viral proteins, like proteins that coat the outside of the virus, as well as viral DNA or RNA. These molecules, when identified in a virus, are called pathogen associated molecular patterns (PAMPs). Certain immune cells can display pattern recognition receptors (PRRs) on their cell membranes or internal endosomal membranes that can detect PAMPs and stimulate the release of cytokines. In addition, other immune cells can actually recognize if damage has occurred from a viral infection. This is a way that the body can detect the virus in a secondary manner through signs of a viral presence, not the virus itself (Mueller and Rouse 2008; Amarante-Mendes et al. 2018). Interestingly, the cells of the immune system are said to be surveying the environment and putting proteins that they find in the body in particular categories. They are “continuously sampling these proteins” in the form of short peptides (protein fragments) to ensure the security of the body (Nicholson 2016). Scientists note that about 70% of lymphocytes in the body are circulating, checking for signs of foreign invaders (Ross and Pawlina 2011).
Host Defense and Parasite Evasion
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
As an example of an inducible system, plants express pattern recognition receptors (PRR) on their cell surfaces that recognize and bind common and conserved molecules associated with a particular group of pathogens known as pathogen-associated molecular patterns (PAMPs) (Figure 4.5). If a particular PRR is engaged by a PAMP, then PAMP-triggered immunity is activated. PAMP-triggered immunity is also called pattern-triggered immunity, either of which may be referred to as PTI. PTI involves activation by fairly nonspecific PAMPs of an intracellular signaling pathway that can lead to relatively generic responses such as strengthening of cell walls to prevent infection or production of lytic enzymes or antimicrobial compounds.
Vaccine Adjuvants in Immunotoxicology
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
Active immunity occurs when encountering a specific antigen or with the transfer of the antibodies protecting against antigens. It is acquired through immunization or getting through the disease itself (Baxter 2007). Moreover, the immune system usually responds within hours thanks to the presence of memory B and T cells when encountering the agent again later. During the active immunity process, the main mechanism providing the relation between innate immunity and adaptive immunity which is acquired weeks later is the ability to perceive the pathogen-associated molecular patterns (PAMPs) which innate immunity considers foreign substances (Peterfalvi et al. 2019; Maughan, Preston, and Williams 2015). This recognition occurs via the class-specific pattern recognition receptor (PRR) which is available in the innate immune system. The most important PRR in innate immunity is a toll-like receptor (TLR). The innate immune system considers PAMPs in a microorganism as a signal of danger and stimulates the adaptive immune system (Ivanov et al. 2020). Antigen-presenting cells (APCs), which are present in the circulation system and are the supervisory components of the immune system, are the group of cells which encounters a pathogen first and define it as “foreign.”
Pyroptosis in neurodegenerative diseases: What lies beneath the tip of the iceberg?
Published in International Reviews of Immunology, 2023
Mengli Yue, Li Xiao, Rui Yan, Xinyi Li, Wei Yang
The recognition and interaction between pattern recognition receptors (PRR) and damage-associated molecular patterns (DAMP) or pathogen-associated molecular patterns (PAMP) are the first step of pyroptosis. The DAMPs are endogenous molecules that are released from damaged or dying cells, Pathogen-associated molecular patterns (PAMPs) are small molecular motifs conserved within groups of pathogens. They can both activate innate immunity via interaction with pattern recognition receptors (PRR) [3]. Only some sensor PRRs which are capable of forming the inflammasome can initiate pyroptosis after sensing corresponding signals [4]. Nod-like receptor family protein 1 (NLRP1), NLRP3, NLR-family CARD-containing protein 4 (NLRC4), Absent in melanoma 2 (AIM2) and pyrin are the most currently studied signaling PRRs, others have also been reported. Their corresponding stimuli are listed in Table 1.
Androgen receptor, a possible anti-infective therapy target and a potent immune respondent in SARS-CoV-2 spike binding: a computational approach
Published in Expert Review of Anti-infective Therapy, 2023
Ashfaq Ahmad, Zhandaulet Makhmutova, Wenwen Cao, Sidra Majaz, Amr Amin, Yingqiu Xie
Subsequent studies have highlighted the potentials of AR as anti-COVID-19 therapy, whereas anti-androgen treatment has abated SARS-CoV-2 infection in prostate cancer patients or in proposal of vaccine [7–12]. Recently we have demonstrated AR involvement in RBD binding through docking experiments [11], and the potential of AR in SARS-CoV-2 entry has been studied, but whether AR is directly involved in mediating an immune response during COVID-19 disease is debatable. AR contains a ligand binding domain (LBD), DNA binding domain (DBD), and activated functional (AF1, AF2) domains which reflect the domain-mediated roles in transcriptional regulation of target genes [1]. The S1 subunit of the SARS-CoV-2 spike protein induces the angiotensin II type 1 receptor (AT1)-mediated signaling cascade in human epithelial cells, which upon infection can initiate an inflammatory response of the innate immune system. This immune response is brought about by recognition of pathogen-associated molecular patterns (PAMPs) by different pattern recognition receptors (PRRs), e.g, Toll-like, NOD-like, and RIG-I like receptors [2]. Similarly, AR also acts as a ligand-activated transcription factor of the nuclear receptor (NR) super family which interacts with a number of proteins, such as the human NCOA1, NCOA2, NCOA3, NCOA4, and MAGEA11 and associates with the LXXLL and FXXLF motifs via the ligand-binding domain (LBD) [3].
Conventional amphotericin B elicits markers of immunogenic cell death on leukemic blasts, mediates immunostimulatory effects on phagocytic cells, and synergizes with PD-L1 blockade
Published in OncoImmunology, 2022
G. Kofla, C. Radecke, M. Frentsch, W. Walther, S. Stintzing, H. Riess, L. Bullinger, I-K. Na
To prevent adverse inflammatory effects with catastrophic consequences to the whole-body homeostasis, the physiological form of regulated cell death (RCD) is a process relatively “invisible” to the adaptive immune system, resulting in a silent or tolerogenic phagocytic clearance.1 However, in some specific cases, cells that succumb to stress can display sufficient antigenicity and adjuvanticity to elicit an adaptive immune response, a process referred to as immunogenic cell death (ICD).2–4 This rare type of apoptosis with immunogenic abilities is usually preceded by premortal activation of the ER stress response and results in enhanced adjuvanticity by up-regulation and secretion of danger-associated molecular patterns (DAMPs). They act analogously to the pathogen-associated molecular patterns (PAMPs) by stimulation of pattern recognition receptors (PRRs) expressed by innate immune cells.2,5,6 Consequently, DAMPs released after ICD can stimulate maturation of the antigen presenting cells (APCs) capable of eliciting adaptive immune responses, followed by the establishment of an immunological memory.5,7