The Basics of Immunology

2021 ◽  
Author(s):  
Heinz-Josef Schmitt ◽  
Nathalie Garçon

Humans have defense mechanisms against micro-organisms exemplified by the immune system that consists of an unspecific (“innate immunity”) and specific (“adaptive immunity”) arm, leading to an effective response via humoral and cellular mechanisms. Innate immunity is activable at any time (skin, tears, ciliae, …). It includes recognition of various chemical patterns on microorganisms. Such chemical structures are detected by macrophages or dendritic cells, which travel to the draining lymph nodes and are presented to cells of the adaptive immune system. The adaptive immune system is highly specific against individual microorganisms and directed against non-self-structures. It needs days to weeks to be effective and it induces immune memory, allowing for an immediate defense response upon re-infection. As a result of presentation of non-self-structures to the adaptive immune system, highly specific antibodies and cells are generated which may kill/neutralize microbial invaders. Currently, antibody responses are the cornerstone to vaccine licensure. Functional antibody tests detecting killing/neutralizing ability are the cornerstone of vaccine-induced immunity. Tests for cell-mediated immunity are also considered. Antibody responses to vaccines can be evaluated as o Geometric Mean Titer (GMT) or Geometric Mean Concentration (GMC) o Fold-rise pre/post vaccination o Percentage of study subjects achieving a clinically relevant amount of antibody (“sero-responders”) o Reverse Cumulative Distributions (RCDs), ideally showing data pre- and post-vaccination.

2021 ◽  
Author(s):  
Phillip Wibisono ◽  
Shawndra Wibisono ◽  
Jan Watteyne ◽  
Chia-Hui Chen ◽  
Durai Sellegounder ◽  
...  

A key question in current immunology is how the innate immune system generates high levels of specificity. Like most invertebrates, Caenorhabditis elegans does not have an adaptive immune system and relies solely on innate immunity to defend itself against pathogen attacks, yet it can still differentiate different pathogens and launch distinct innate immune responses. Here, we have found that functional loss of NMUR-1, a neuronal GPCR homologous to mammalian receptors for the neuropeptide neuromedin U, has diverse effects on C. elegans survival against various bacterial pathogens. Transcriptomic analyses and functional assays revealed that NMUR-1 modulates C. elegans transcription activity by regulating the expression of transcription factors, which, in turn, controls the expression of distinct immune genes in response to different pathogens. Our study has uncovered a molecular basis for the specificity of C. elegans innate immunity that could provide mechanistic insights into understanding the specificity of vertebrate innate immunity.


Blood ◽  
2008 ◽  
Vol 112 (5) ◽  
pp. 1750-1758 ◽  
Author(s):  
James L. Wynn ◽  
Philip O. Scumpia ◽  
Robert D. Winfield ◽  
Matthew J. Delano ◽  
Kindra Kelly-Scumpia ◽  
...  

Abstract Neonates exhibit an increased risk of sepsis mortality compared with adults. We show that in contrast to adults, survival from polymicrobial sepsis in murine neonates does not depend on an intact adaptive immune system and is not improved by T cell–directed adaptive immunotherapy. Furthermore, neonates manifest an attenuated inflammatory and innate response to sepsis, and have functional defects in their peritoneal CD11b+ cells. Activation of innate immunity with either a Toll-like receptor 4 (TLR4) or TLR7/8 agonist, but not a TLR3 agonist, increased the magnitude, but abbreviated the early systemic inflammatory response, reduced bacteremia, and improved survival to polymicrobial sepsis. TLR4 agonist pretreatment enhanced peritoneal neutrophil recruitment with increased oxidative burst production, whereas the TLR7/8 agonist also enhanced peritoneal neutrophil recruitment with increased phagocytic ability. These benefits were independent of the adaptive immune system and type I interferon signaling. Improving innate immune function with select TLR agonists may be a useful strategy to prevent neonatal sepsis mortality.


2019 ◽  
Vol 18 (1) ◽  
pp. 76-83
Author(s):  
V. S. Sviridova ◽  
P. Yu. Isaev ◽  
V. V. Klimov ◽  
M. I. Romanova ◽  
N. S. Koshkarova

Over the last decade the role of innate immunity has been known to be crucial for the activation of adaptive immune system. The main triggers that upregulate reactions of innate immunity are small exogenous molecules with conserved motifs, molecular patterns. The article discusses a variety of possible roles of molecular patterns in the immune mechanisms, including the participation of Allergen Associated Molecular Patterns (AAMPs) in allergic processes.


2009 ◽  
Vol 1 (1) ◽  
pp. 32
Author(s):  
A Guntur Hermawan

Over the past decade, sepsis has been diagnosed according to consensus guidelines established in 1991 as an infection in addition to the symptoms of systemic inflammatory response syndrome (SIRS). In addition to the previous criteria, the 2001 conference added several new diagnostic criteria for sepsis. Of particular interest was the inclusion of the biomarkers procalcitonin (PCT) and C-reactive protein (CRP), despite the overall conclusion that it was premature to use biomarkers for sepsis diagnosis. The primary recommendation of the panel was the implementation of the Predisposition, insult Infection, Response, and Organ dysfunction (PIRO).The immune system has traditionally been devided into innate and adaptive components, each of which has a different role and function in defending the host against infectious agents. Stimulation of different TLRs induces distinct patterns of gene expression, which not only leads to the activation of innate immunity but also increasing evidence supports an additional critical role for TLRs in orchestrating the development of adaptive immune responses.The superantigens are able to induce toxic shock syndrome and can sometimes cause multiple organ failure via adaptive immune system. The superantigenic activity of the bacterial exotoxins can be attributed to their ability to cross-link major histocompatibility complex class II molecules on antigen-presenting cells outside the peptide groove with T-cell receptors to form a trimolecular complex. This trimolecular interaction leads to uncontrolled release of a number of proinflammatory cytokines. Proinflammatory cytokines especially IFN-γ and TNF-α, the key cytokines causing toxic shock syndrome.KEYWORDS: sepsis, innate immunity, adaptive


Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 913
Author(s):  
Carlos Jiménez-Cortegana ◽  
Ana López-Saavedra ◽  
Flora Sánchez-Jiménez ◽  
Antonio Pérez-Pérez ◽  
Jesús Castiñeiras ◽  
...  

Leptin is an important regulator of basal metabolism and food intake, with a pivotal role in obesity. Leptin exerts many different actions on various tissues and systems, including cancer, and is considered as a linkage between metabolism and the immune system. During the last decades, obesity and leptin have been associated with the initiation, proliferation and progression of many types of cancer. Obesity is also linked with complications and mortality, irrespective of the therapy used, affecting clinical outcomes. However, some evidence has suggested its beneficial role, called the “obesity paradox”, and the possible antitumoral role of leptin. Recent data regarding the immunotherapy of cancer have revealed that overweight leads to a more effective response and leptin may probably be involved in this beneficial process. Since leptin is a positive modulator of both the innate and the adaptive immune system, it may contribute to the increased immune response stimulated by immunotherapy in cancer patients and may be proposed as a good actor in cancer. Our purpose is to review this dual role of leptin in cancer, as well as trying to clarify the future perspectives of this adipokine, which further highlights its importance as a cornerstone of the immunometabolism in oncology.


2006 ◽  
Vol 13 ◽  
pp. S422 ◽  
Author(s):  
Veronika von Messling ◽  
Nicholas Svitek ◽  
Roberto Cattaneo

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