Biological Sciences
Immune Response
The immune response is the body's defense mechanism against foreign invaders, such as pathogens and harmful substances. It involves a complex network of cells, tissues, and organs that work together to identify and eliminate these threats. The immune response can be categorized into innate and adaptive immunity, each playing a crucial role in protecting the body from infections and diseases.
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12 Key excerpts on "Immune Response"
eBook - PDF- Mary Ann Clark, Jung Choi, Matthew Douglas(Authors)
- 2018(Publication Date)
- Openstax(Publisher)
The immune factors identify the nature of the pathogen, strengthen the corresponding cells and molecules to combat it efficiently, and then halt the Immune Response after the infection is cleared to avoid unnecessary host cell damage. The immune system can remember pathogens to which it has been exposed to create a more efficient response upon reexposure. This memory can last several decades. Features of the immune system, such as pathogen identification, specific response, amplification, retreat, and remembrance are essential for survival against pathogens. The Immune Response can be classified as either innate or active. The innate Immune Response is always present and attempts to defend against all pathogens rather than focusing on specific ones. Conversely, the adaptive Immune Response stores information about past infections and mounts pathogen-specific defenses. Chapter 42 | The Immune System 1301 42.1 | Innate Immune Response By the end of this section, you will be able to do the following: • Describe physical and chemical immune barriers • Explain immediate and induced innate Immune Responses • Discuss natural killer cells • Describe major histocompatibility class I molecules • Summarize how the proteins in a complement system function to destroy extracellular pathogens The immune system comprises both innate and adaptive Immune Responses. Innate immunity occurs naturally because of genetic factors or physiology; it is not induced by infection or vaccination but works to reduce the workload for the adaptive Immune Response. Both the innate and adaptive levels of the Immune Response involve secreted proteins, receptor-mediated signaling, and intricate cell-to-cell communication. The innate immune system developed early in animal evolution, roughly a billion years ago, as an essential response to infection.
- Mary Keogan, Eleanor M. Wallace, Paula O'Leary(Authors)
- 2006(Publication Date)
- Routledge(Publisher)
1 BASIC IMMUNOLOGY INTRODUCTION This part outlines basic aspects of how the immune system functions to protect us against pathogens. Some basic mechanisms underlying allergy and hypersensitivity are also included. The aim of this part is to provide a concise summary of essential aspects of immunity required to understand immunological diseases, investigations and treatment. There are many excel- lent textbooks available, which provide additional detail and more detailed explanation. We have, however, aimed to include sections describing clinically relevant aspects of basic immunology that are frequently scattered, such as ontogeny of the Immune Response, as well as sections aimed at integrating information. REFERENCES Davies, D. H., Halablab, M. A., Clarke, J., Fox, F. E. G. and Young, T. W. K. (1999) Infection and Immunity, London: Taylor & Francis. Janeway, C. A., Travers, P., Hunt, S. and Walport, M. (2000) Immunobiology: The Immune System in Health and Disease, New York: Garland Publishing. Nairn, R. and Helbert, M. (2002) Immunology for Medical Students, London: Mosby. Parham, P. (2000) The Immune System, London: Elsevier Science. KEY DEFINITIONS Every effort has been made to explain new terms as this part progresses. However occasionally, particularly in the early chapters, fully explaining each term was too cumbersome. This list is not a complete glossary, merely a list of key definitions with which you should be familiar before reading this section. Acute phase response (APR) Changes in metabolism occurring in response to inflammation, including inflammation caused by infection. The APR results in fever and changes in protein production. Production of transport proteins (such as albumin) is reduced, while production P A R T 1 B A S I C I M M U N O L O G Y of protective proteins (immune system molecules, clotting factors and protease inhibitors) is increased.
eBook - PDF- Gerald Karp, Janet Iwasa, Wallace Marshall(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
The cells of the immune system engage in a type of molec- ular screening by which they recognize “foreign” macromole- cules, that is, ones with structures different from those of the body’s normal macromolecules. If foreign material is encoun- tered, the immune system mounts a specific and concerted attack against it. The weapons of the immune system include (1) cells that kill or ingest infected or altered cells and (2) sol- uble proteins that can neutralize, immobilize, agglutinate, or kill pathogens. Pathogens, in turn, are continually evolving countermechanisms to avoid immune destruction. The fact that humans suffer from a number of chronic infective dis- eases, such as AIDS (caused by a virus), tuberculosis (caused by a bacterium), and malaria (caused by a protozoan) illustrates how our immune systems are not always successful in combat- ing these microscopic pathogens. In some cases, the immune system may mount an inappropriate response that attacks the body’s own tissues. As discussed in the Human Perspective fea- ture (Section 17.3), these incidents can lead to serious disease. It is impossible to cover the entire subject of immunity in a single chapter. Instead, we focus on a number of selected aspects that illustrate principles of cell and molecular biology discussed in previous chapters. First, however, it is necessary to examine the basic events in the body’s response to the pres- ence of an intruding microbe. The outer surface of the body and the linings of its internal tracts provide an excellent barrier to prevent pen- etration by viruses, bacteria, and parasites. If these surface Spleen Lymph nodes Secondary lymphoid tissues Primary lymphoid organs Tonsil Peyer’s patches of intestine Appendix Lymph vessels Bone marrow (origin of B cells and T cells and site of B-cell maturation) Thymus (site of T-cell maturation) Source: From Wessner, Microbiology, 1e, Figure 20.4. John Wiley & Sons Publishers. Reprinted by permission of John Wiley & Sons, Inc.
- Nicola Bellomo, Carlo Bianca(Authors)
- 2011(Publication Date)
- World Scientific(Publisher)
PART 1 Immune System, Wound Healing Process, and System Biology This page intentionally left blank This page intentionally left blank Chapter 3 The Immune System: A Phenomenological Overview 3.1 Introduction The immune system is constituted of a network of cells, tissues, and organs that operate collectively to protect the body from bacterial, parasitic, fungal, viral in-fections, and from the growth of tumor cells. The cells involved are called white blood cells, or leukocytes, which act to seek out and destroy disease-causing or-ganisms or substances. Many of these cell types have specialized functions and depend on the T helper subset for activation signals in the form of secretions for-mally known as cytokine, lymphokines, or more specifically interleukins. The cells of immune system attack, through a sequence of actions called the Immune Response, infectious agents and substances that invade the human body and cause diseases. The defence also applies to cells that, due to inflammation, may pro-gressively degenerate into cancer cells (in general mutated cells). Immune cells are able to perform complex tasks, such as learning , acquire the ability to distinguish between host entities ( self ) and foreign or infected enti-ties ( non-self ), and evolve in time to progressively improve their overall defence ability, while retaining memory of previous encounters with foreign agents for a quicker response in the case of re-infection, and constantly updating their reactive potential. The cells of the immune system, globally called leukocytes or white blood cells , communicate via cell-to-cell contact or via chemical signals by means of specific secreted substances, and cooperate continuously by monitoring the envi-ronment, detecting, and attacking foreign infectious agents.
eBook - PDF- Nima Rezaei(Author)
- 2017(Publication Date)
- IntechOpen(Publisher)
Chapter 6 Physiology and Pathology of Innate Immune Response Against Pathogens José Luis Muñoz Carrillo, Flor Pamela Castro García, Oscar Gutiérrez Coronado, María Alejandra Moreno García and Juan Francisco Contreras Cordero Additional information is available at the end of the chapter http://dx.doi.org/10.5772/intechopen.70556 Abstract Pathogen infections are recognized by the immune system, which consists of two types of responses: an innate Immune Response and an antigen-specific adaptive Immune Response. The innate response is characterized by being the first line of defense that occurs rapidly in which leukocytes such as neutrophils, monocytes, macrophages, eosinophils, mast cells, dendritic cells, etc., are involved. These cells recognize the pathogen-associated molecular patterns (PAMPs), which have been evolutionarily conserved by the diversity of microorganisms that infect humans. Recognition of these pathogen-associated molecu -lar patterns occurs through pattern recognition receptors such as Toll-like receptors and some other intracellular receptors such as nucleotide oligomerization domain (NOD), with the aim of amplifying the inflammation and activating the adaptive cellular Immune Response, through the antigenic presentation. In the present chapter, we will review the importance of the main components involved in the innate Immune Response, such as dif -ferent cell types, inflammatory response, soluble immune mediators and effector mecha -nisms exerted by the Immune Response against bacteria, viruses, fungi, and parasites; all with the purpose of eliminating them and eradicating the infection of the host. Keywords: innate Immune Response, eosinophils, mast cells, cytokines, inflammatory response, bacteria, fungi, viruses, parasites 1. Introduction The immune system consists of a series of effector mechanisms capable of destroying patho -genic organisms such as bacteria, fungi, viruses, and parasites [ 1].
eBook - PDFBiological Response Modifiers
New Approaches to Disease Intervention
- Paul Torrence(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
2 Basic Concepts of Immunity MARGARET I. JOHNSTON Department of Biochemistry Uniformed Services University of the Health Sciences Bethesda, Maryland I. Introduction 21 A. Historical Perspective 21 B. Humoral versus Cellular Immunity 22 II. Cellular Participants in the Immune System 24 A. Lymphocytes 24 B. Null Cells 30 C. Monocytes-Macrophages 32 D. Introduction to Major Histocompatibility Antigens 34 E. Other Circulating Cells 36 III. Basic Characteristics of the Immune Response 38 IV. Lymphocyte Subpopulations 40 A. T- and B-Cell Cooperation 40 B. T-Cell Subpopulations 40 C. B-Cell Subsets 42 V. Mechanisms of Cell-Cell Communication and Immune Regulation 42 A. Antigen Bridge Model 42 B. Idiotype Recognition , 43 C. Antigen-Specific Factors 44 D. Antigen-Nonspecific Factors 44 VI. Immune Regulation 48 A. The Jerne Hypothesis 48 B. Suppressor T-Cell Circuits 49 C. Other Potential Regulatory Mechanisms 50 D. Tolerance 50 VII. Importance of the MHC Proteins 51 VIII. Summary 53 References 55 I. INTRODUCTION A. Historical Perspective This volume describes several soluble factors that modify biological re-sponses. Many of these so-called biological response modifiers are pro-BIOLOGICAL RESPONSE MODIFIERS 2 1 Copyright © 1985 by Academic Press, Inc. All rights of reproduction in any form reserved. 22 Margaret I. Johnston duced by and/or act on cells that function in the immune system. The purpose of this chapter is to introduce the cells and the activities of the cells that participate in immune reactions, with emphasis on cell-cell commu-nication and regulatory mechanisms, so that scientists without a formal background in immunology can put the pages that follow in proper per-spective. Unraveling the mysteries of the immune process began centuries ago, and any author would be hard pressed to point to a beginning of immunology. However, the work of Edward Jenner in the late 1790s is often cited as one of the earliest landmarks in the study of our defense against disease.
- Michael Kennamer(Author)
- 2020(Publication Date)
- Cengage Learning EMEA(Publisher)
Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 48 CHAPTER 4 The Immune Response Learning Objective 4.3 Explain how the immune system responds to pathogens entering the body. Key Terms: lymphocytes, nonspecific immunity, specific immunity When pathogens enter the body, the immune system responds. Immunity typically falls into one of two categories. Specific immunity uses lymphocytes (T cells and B cells) to provide protection against specific pathogens. Nonspecific immunity uses neutrophils, macrophages, monocytes, and natural killer cells as a more general defense against pathogens. A description of each type of immunity follows. 1. Which type of immunity uses lymphocytes to provide protection against specific pathogens? a. Nonspecific immunity b. Macrophages c. Autoimmune d. Specific immunity 2. Which type of immunity utilizes natural killer cells? a. Nonspecific immunity b. Macrophages c. Autoimmune d. Specific immunity Knowledge Check 4.3 2. What term is used to describe what occurs when the immune system erroneously reacts to any part of the body that it perceives as foreign? a. Cancer b. Tumor c. Fever d. Autoimmune Copyright 2021 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The Immune System UNDER THE MICROSCOPE ● Interview someone you know who has an autoimmune disease. Seek to discover the obstacles they face on a daily basis. ● Search the literature to learn about other famous people who have (or had) an autoimmune disease.
eBook - PDF- Arthur T. Johnson(Author)
- 2018(Publication Date)
- CRC Press(Publisher)
This mechanism particularly protects against viral infections that incorporate viral RNA within the genetic duplicating mechanisms of the host cell. This system uses a type of RNA, called Piwi-interacting ( Continued ) Diagram of the human Immune Response. Both chemical and cellular defenses are recruited. (Redrawn from Campbell, N. A. et al., Biology , 5th ed., Addison Wesley Longman, Menlo Park, CA, 1999.) IMMUNE SYSTEM AS A MODEL OF ULTRA-REDUNDANCY (Continued) 545 Biological Responses in Context RNA (piRNA) to check if the foreign RNA has been seen before. If it has not, then it is recognized as “non-self” and epigenetically silenced (RNAe, or RNA-induced epigenetic silencing). Microbes attempting to enter the body must first get past the skin and mucous membranes. These pose a physical barrier and are rich in scavenger cells and Ig A antibodies. Next, there are the nonspecific defenses that attack all invaders. Patrolling scavenger cells, complement, and other enzymes and chemicals form this second line of defense. Then, infectious agents must face specific antibodies and cell defenses. If the body has been assaulted before by the same kind of antigen, then the B cell is ready to produce plasma cells that, in turn, manufacture large quantities of a specific antibody. These antigens activate B cells to recognize them upon the first exposure (Figure). T cells are recruited. These are very powerful cells that could kill any kind of cells of the body if not carefully controlled. Thus, there is a complicated arrangement to assure that T cells act only on precise targets at close range. T cells do not mature to their full lethal capabilities until a macrophage has ingested a cell and produced cytokines that allow the T cell to mature. Proper development of the immune system depends strongly on early exposures in the digestive tract (Brandtzaeg, 2007).
eBook - PDF- Frank J. Fenner, B. R. McAuslan, C. A. Mims(Authors)
- 2013(Publication Date)
- Academic Press(Publisher)
I INTRODUCTION Vertebrates differ from all other CHAPTER 10 living organisms in their ca-pacity to respond in a highly specific way to foreign macro-PathOgeneSIS: The Immune molecules, notably proteins, by Response producing an Immune Response. Such foreign macromolecules, | which are called antigens, are said to be immunogenic when they produce a positive response and tolero-genic when their administration results in immunological tolerance. The mi-croorganisms and viruses that cause infections constitute the most important natural antigens, and the word immunity is used to describe the specific type of host resistance associated with the Immune Response. Both virology and immunology can trace their beginnings to the investiga-tions of Edward Jenner (1798) into the protection of man against smallpox by prior inoculation with cowpox virus, and it is common knowledge that individ-uals who have recovered from smallpox, measles, or chickenpox are specifically resistant to second attacks. Since immunology is now an even broader and more rapidly advancing field of biological science than virology, we cannot hope to cover its complexities in this chapter. The interested reader is referred to some of the excellent introductory texts now available (Burnet, 1969, Humphrey and White, 1970), and to recent review articles dealing with particular facets of the subject. The specific altered responsiveness of the immune host is expressed in two ways, both mediated by cells of the lymphocyte series: The synthesis of specific immunoglobulins, the antibodies, and the development of cell-mediated immu-nity, one expression of which is delayed hypersensitivity. THE IMMUNOGLOBULINS All antibodies belong to a single group of globular proteins that have been called the immunoglobulins (World Health Organ., 1964), and have been sub-divided into five classes by immunoelectrophoresis.
eBook - PDFViruses
Biology, Applications, and Control
- David Harper(Author)
- 2011(Publication Date)
- Garland Science(Publisher)
The complement system Complement is the name given to a complex set of proteins that are pres-ent in normal blood. Although first identified as enhancers of the antibody activity by producing cytotoxic effects where antibody is bound (see Section 4.2), the complement system is also a significant part of the innate Immune Response. CHAPTER 4 Immune Response and Evasion 73 Complement is activated by three pathways: by antigen-bound antibodies (the classical pathway), by the specific binding of a lectin to mannose sugar residues on bacteria or viruses (the MB lectin pathway), or by specific struc-tures on the surfaces of some pathogens which stabilize the initial enzymes of the activation process (the alternative pathway). Activation by any of these pathways initiates a similar series of enzymic reactions, each of which amplifies the previous stages (referred to as a cas-cade). This means that a small initial response can become very large by the time the complement cascade is completed. Activated complement can act in one of three ways: • Binding to the surface of pathogens and making them better targets for phagocytosis by cells bearing complement receptors (opsonization) • Providing a chemokine-like (pro-inflammatory) attractant activity for phagocytes • Creating pores in membranes via the membrane attack complex (often targeted by bound antibody) Balancing the inherent amplification of the complement system, activated complement tends to be restricted to the surfaces on which the cascade was initiated. This is an important control of such a powerful and destructive process. 4.2 THE SEROLOGICAL Immune Response The serological Immune Response is mediated by antibodies (more prop-erly, immunoglobulins ), which are glycoproteins adapted to circulation in the blood, which have the ability to bind to specific molecular structures on their target antigen.
- Mary Keogan, Eleanor M. Wallace, Paula O'Leary(Authors)
- 2006(Publication Date)
- Routledge(Publisher)
Together, the innate and adaptive immune systems provide an amazing defence system. Despite the fact that we are surrounded by a multitude of potentially pathogenic microorganisms, we rarely succumb to infection. Many infections are eliminated by the innate immune system and cause no disease. Infections that cannot be resolved by innate immunity trigger adaptive immunity, which usually eliminates the infection (often before we are aware of it) and generates immunological memory.WHAT HAPPENS WHEN THE IMMUNE SYSTEM GOES WRONG?
The immune system is only apparent when it goes wrong, and virtually any clinical presentation may be the sign of an underlying immunological disorder. The immune system must find a balance between producing a life-saving response to infection and tissue-damaging reactions. It is also essential that the immune system only mounts a vigorous response to pathogens that pose a threat, and ignores our own tissues, as well as environmental substances including foods and medicines.Immunodeficiency diseases
Immunodeficiency means a failure of the immune system to protect us from infection. It may be primary (due to an intrinsic defect in the immune system) or secondary, (due to drugs, infection, malnutrition etc.).Overactivity of part of the immune system
The Immune Response can cause incidental tissue damage as well as the intended removal and/or destruction of microorganisms. Additionally the immune system may fail to distinguish between pathogens and innocuous stimuli such as pollen or self-tissue. In this case a vigorous Immune Response causes disease.Allergy
An over-response to environmental stimuli, which pose no threat, is called allergy. Several different immune mechanisms may be involved. The most common mechanism causes rapid responses varying in severity from hayfever to potentially fatal anaphylactic shock.Autoimmunity
Autoimmune diseases can affect any tissue in the body, and occur when the immune system fails to distinguish between self (which should be ignored) and non-self (which should be attacked). Many autoimmune diseases can be diagnosed by testing for immune products (antibodies) against self-tissues in patients’ blood.
eBook - PDF- Anthony A. Nash, Cedric A. Mims, John Stephen(Authors)
- 2000(Publication Date)
- Academic Press(Publisher)
6 The Immune Response to Infection Antibody response T-cell-mediated Immune Response Natural killer cells Macrophages, polymorphs and mast cells Complement and related defence molecules Conclusions concerning the Immune Response to microorganisms References 156 167 172 173 176 179 181 The Immune Response is conveniently divided into the antibody and the cell-mediated component, the latter being transferable from one individual to another by lymphocytes but not by serum. Antibodies, since they can be tested and assayed without great difficulty, were the first to receive attention with the discovery of antibodies to tetanus and diphtheria toxins in the 1890s. Cell-mediated immunity (CMI) in the form of delayed hypersensitivity was described more than 50 years ago, and has received intensive study in the past 30 years. Specific antibodies and CMI are induced in all infections, but the magnitude and quality of these responses varies greatly in different infections. It is not often that the microbial antigens concerned have been individu- ally defined or identified. More importantly, we have rarely identified the microbial antigens that induce protective Immune Responses. Most antigens are proteins or proteins combined with other sub- stances, but polysaccharides and other complex molecules also function as antigens. Substances called haptens, small molecules such as sugars, cannot by themselves stimulate antibody production, but do so when coupled to a protein. An antigen stimulates the production of antibodies that react specifically with that antigen. The reaction can be thought of as similar to that between lock and key, and it is specific in the sense that antibody produced against diphtheria toxin does not react with tetanus toxin. An antibody may, however, have weaker reac- tivity against antigens closely related to the one that stimulated its production.
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