The Immune System, Third Edition

Gregory Stewart, Donna Bozzone

Description

Praise for the previous edition:

SSLI "Honor Book," Science, Grades 7–12 category—Society of School Librarians International

The immune system is crucial to the normal functioning of the human body. As the body's "military," it prevents invaders from entering and destroys those who slip past its defenses. The Immune System, Third Edition discusses the human body's fundamental defense system, from its component parts to what happens when the body's defenses are breached. Common and uncommon immune disorders are also discussed, as are potential new therapies to enhance or repair the immune system. Packed with full-color photographs and illustrations, this absorbing book provides students with sufficient background information through references, websites, and a bibliography.

Sujets

• Life Sciences
• Sciences et techniques
• Biology
• Virology
• Medicine
• Immunology
• Research
• Discovery
• Science

Informations

• Publié par: Infobase Publishing
• Date de parution: 01 août 2021
• Nombre de lectures: 0
• EAN13: 9781646937219
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

The Immune System, Third Edition
Copyright © 2021 by Infobase
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For more information, contact:
Chelsea House An imprint of Infobase 132 West 31st Street New York NY 10001
ISBN 978-1-64693-721-9
You can find Chelsea House on the World Wide Web at http://www.infobase.com
Contents Chapters How Important Is the Immune System? Innate Immunity and Defenses Cells, Tissues, and Organs of the Immune System Humoral Immunity Antibody Synthesis Cell-Mediated Immunity Importance of Vaccines Allergies and Autoimmune Diseases Immune Reactions as a Scientific Tool Support Materials Glossary Bibliography Further Resources About the Authors Index
Chapters
How Important Is the Immune System?

Introduction
You are probably familiar with many systems of the human body. The skeletal system includes the bones, which serve to support and protect the rest of the body. The muscular system allows the body to move, and the digestive system allows us to take in food and extract its energy to build and maintain the body. The respiratory system is responsible for bringing oxygen into the body and the circulatory system sends blood to every tissue and cell where that oxygen is delivered. It is relatively easy to understand the functions and the importance of these systems, but what about the immune system?
The immune system is extremely important to us. Its job is to help the body avoid and fight infections. The immune system also prevents the development of certain types of cancer. To illustrate the importance of this system, we will consider examples where the immune system does not function properly: infectious diseases, allergic reactions and autoimmune diseases. 
Infectious Disease and History
Every historical age of human history seems to be defined by one or more catastrophic disease. In medieval Europe, it was "the black plague," or bubonic plague. From 1347–1353, outbreaks occurred in villages and cities throughout the continent and, in one estimate, led to the death of as much as one-half of Europe's population. 1 The histories of sub-Saharan Africa, India, and the Mediterranean region of Europe are marked with cycles of malaria, a disease transmitted by mosquitoes, that nearly one-half of the world's population is still at risk of contracting. 2 Tuberculosis became the principal disease of the Romantic and Victorian periods throughout Europe. This wasting disease was so prevalent that it became a central and recurring theme in much of the art and literature of the time. When you hear of a character suffering from or dying of "consumption," the author is referring to tuberculosis. 
During periods of exploration and colonization, Europeans traveling to faraway places brought home with them exotic products, such as new fruits, silks, and spices, but they also returned with previously unknown diseases, including the sexually transmitted disease, syphilis. Eventually infectious disease outbreaks altered the history of the Western Hemisphere. Before their exposure to Europeans, Native Americans had been free from many of the infectious diseases that were common in Europe and the rest of the Old World. However, once they were exposed to these infectious diseases, the Native Americans were extremely likely to become sick from and succumb to these diseases. In one instance in 1520, a small band of conquistadors led by Hernán Cortés (allied with more numerous Native American rivals of the Aztecs) conquered Tenochtitlán, the capital of the Aztec empire, after smallpox killed half of the city's population, including the Aztec ruler Cuitláhuac. 3 This pattern repeated itself again and again, throughout the Western Hemisphere as Europeans came into contact with Native American civilizations. Their germs caused catastrophic death in the Native American population.
Infectious disease shaped modern history too. At the turn of the 20th century, it was common for parents to have large families of six or more children as many children never lived to adulthood. Children often died from one of the rampant, childhood infectious diseases: influenza, measles, typhus, typhoid fever, and scarlet fever. During the 1920s and through the 1940s, the United States was devastated by polio, a disease that killed many children, and left many other children partially paralyzed.
Acquired Immune Deficiency Syndrome: AIDS
One of the most serious infectious diseases of the late 20th century, acquired immune deficiency syndrome (AIDS) continues to be a worldwide problem in the 21st century. AIDS is a global pandemic, affecting people on all continents except Antarctica. While AIDS is a significant health care challenge in the United States, there are areas of the world where AIDS is a much more serious problem. In 2019 it was estimated that eastern and southern Africa had 20.7 million people with HIV, or the human immunodeficiency virus, the causative agent for AIDS. 4 Globally, 38 million people are afflicted with this progressive disease. 5 At first, the onset is slow with only mild symptoms that can easily be mistaken for the common cold or flu. As AIDS progresses, the symptoms worsen. The patient becomes chronically ill and loses weight. In Africa, where HIV is thought to have originated, people call AIDS "the wasting disease" because of the relentless deterioration of health, coupled with the rapid loss of weight.

This graphic shows the global prevalence of HIV in adults (persons aged 15-49) in 2019.
Source: Infobase.
Although AIDS first became noticeable in the United States in gay men and in intravenous drug users, everyone is vulnerable to contracting the disease. AIDS does not specialize or discriminate.  Because HIV is spread by bodily fluids, activities where fluids are shared between people can be risky. These behaviors include sex, intravenous drug use, and blood transfusions. AIDS spreads by what people do, not according to who they are.
The History of AIDS in the United States
The manner in which the United States reacted to the first cases of AIDS is an interesting case study that reveals how bias can impact public health decisions and actions. 
In the 1960s and 1970s, decades that preceded the AIDS pandemic, the United States vigorous efforts to fight infectious disease was considered very successful. For example, smallpox, once one of the most feared diseases in the world, had been completely eliminated. The United States was also well on its way to eradicating another devastating disease, tuberculosis. So many diseases were being managed successfully with vaccines and antibiotics that some of the leading scientists of the time suggested that medical microbiology would soon become an extinct area of study. Colleges and universities that trained microbiologists began to reduce the focus on disease and increase the emphases on biochemistry, molecular genetics, and environmental microbiology. Unfortunately, this overconfidence had consequences. When new cases of unexplained infections began to occur in 1981, medical and public health professionals were unprepared to deal with this unfolding new crisis.
The response to AIDS in the United States was slow. In June of 1981, a report appeared in a weekly paper published by the Centers for Disease Control and Prevention (CDC). This weekly report, known as Morbidity and Mortality Weekly Report (MMWR), is an essential tool for communicating information about diseases, illnesses, and accidents that affect human health. This particular issue reported that five young men from Los Angeles were treated at three different hospitals in the Los Angeles area for a type of pneumonia called Pneumocystis carinii pneumonia (PCP). These men appeared to be in good health, which was unexpected because this form of pneumonia is usually seen only in people who are so ill that their immune systems are not functioning properly. The men did not know each other, and their only common characteristic was that they were gay. Laboratory blood work indicated that all five men had an unusually low level of a kind of white blood cell called the T-helper cell, or T H cell. T-helper cells, a type of lymphocyte, are essential for activating the immune response. With such low levels of T-helper cells in the blood, the bodies of these five men could not fight the Pneumocystis carinii microbes in their lungs, thus causing them to develop pneumonia.
One month later, in July of 1981, the MMWR reported 26 cases of Kaposi's sarcoma, which is a cancer of the lining of the blood vessels. As the tumors grow, the walls of the blood vessels weaken and blood leaks into the surrounding tissues, causing reddish-purple patches that are visible under the skin. All 26 cases were young men: 20 men lived in New York and six lived in California. Again, all of these men were gay and until recently had been in good health. Before this outbreak, Kaposi's sarcoma was known to occur only in older men of Mediterranean descent. Ten of these 26 patients also had PCP, and several others had diseases usually seen only in persons who are severely immunocompromised (having immune systems that do not function properly). A number of explanations were proposed for these unusual cases in young gay men. The government was slow to respond to these diseases and although we cannot be certain why this was so, critics assert that the neglect was due to the fact that all the patients diagnosed with these cases were gay.
Later in 1981, the CDC reported cases of PCP in heroin addicts and other intravenous (IV) drug users. By early the next year, the first case of transmission between heterosexuals was reported. When immune deficiency began to appear in hemophiliacs and other persons who received bl