Book contents
- Frontmatter
- Contents
- List of Contributors
- 1 Basic Components of the Immune System
- 2 Immunological Techniques
- 3 Immune Regulation
- 4 Immunological Aspects of Infection
- 5 Immunological Aspects of Immunodeficiency Diseases
- 6 Autoimmunity
- 7 Chronic Lymphocytic Leukemia
- 8 Immunology of HIV Infections
- 9 Immunological Aspects of Allergy and Anaphylaxis
- 10 Immunological Aspects of Skin Diseases
- 11 Experimental Approaches to the Study of Autoimmune Rheumatic Diseases
- 12 Immunological Aspects of Cardiac Disease
- 13 Immunological Aspects of Chest Diseases: The Case of Tuberculosis
- 14 Immunological Aspects of Gastrointestinal and Liver Disease
- 15 Immunological Aspects of Endocrine Disease
- 16 Immune-Mediated Neurological Syndromes
- 17 Immunological Aspects of Renal Disease
- 18 Immunological Aspects of Transplantation
- Index
4 - Immunological Aspects of Infection
Published online by Cambridge University Press: 18 December 2009
- Frontmatter
- Contents
- List of Contributors
- 1 Basic Components of the Immune System
- 2 Immunological Techniques
- 3 Immune Regulation
- 4 Immunological Aspects of Infection
- 5 Immunological Aspects of Immunodeficiency Diseases
- 6 Autoimmunity
- 7 Chronic Lymphocytic Leukemia
- 8 Immunology of HIV Infections
- 9 Immunological Aspects of Allergy and Anaphylaxis
- 10 Immunological Aspects of Skin Diseases
- 11 Experimental Approaches to the Study of Autoimmune Rheumatic Diseases
- 12 Immunological Aspects of Cardiac Disease
- 13 Immunological Aspects of Chest Diseases: The Case of Tuberculosis
- 14 Immunological Aspects of Gastrointestinal and Liver Disease
- 15 Immunological Aspects of Endocrine Disease
- 16 Immune-Mediated Neurological Syndromes
- 17 Immunological Aspects of Renal Disease
- 18 Immunological Aspects of Transplantation
- Index
Summary
INTRODUCTION
From the moment of birth, the host is constantly exposed to a wide variety of bacteria and viruses. In general, the host manages to either eliminate or ward off these invading organisms, and a symbiosis is achieved between microbes and the host. How does this occur? There are two major pathways to achieve this resistance: nonspecific and adaptive.
NONSPECIFIC RESISTANCE
Nonspecific or natural resistance refers to barriers, secretions, and normal flora that make up our external defenses. Phagocytes and complement are also involved. Mechanical barriers are highly effective, and the skin (our largest organ) is highly suited to this protection (see Figure 4.1); loss of a major part of the skin (secondary to burns, acids, etc.) immediately exposes the host to marked susceptibility to infection. The mucosal lining of mouth and respiratory tract is another excellent defense mechanism. Yet, a defect in the mucosal lining of the respiratory tract, which occurs in cystic fibrosis, results in a heightened susceptibility to many infections. These are examples of a defect in the epithelium or epithelial lining. In general, however, it is the mobilization of the phagocytic cells such as monocytes/macrophages and polymorphonuclear leukocytes that ingest invading microorganisms and kill them.
The polymorpholeukocytes are a large pool of phagocytic cells that are both circulatory and in the bone marrow. Invading organisms trigger an inflammatory cascade, which stimulates these cells to adhere to vascular epithelium and actively migrate toward the infection. Phagocytosis is promoted by opsonins (usually IgG antibody) and complement.
The macrophages reside in the sub-epithelial tissues of the skin and intestine and line the alveoli of the lungs.
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- Essential Clinical Immunology , pp. 45 - 60Publisher: Cambridge University PressPrint publication year: 2009
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