3: Microbiology and Pathology

3 Microbiology and Pathology

1.0 IMMUNOLOGY AND IMMUNOPATHOLOGY

The human body’s immune system is an elegant and elaborate process involving two types of immunity. In general, the body’s first defense mechanism against infection includes anatomic (e.g., skin, mucosal membranes) or physiologic (e.g., temperature, low pH) barriers. When a pathogen invades this physical barrier, the body has two different types of immune responses: the innate (nonspecific) immune response and the acquired (specific/adaptive) immune response. Innate immunity is the body’s early defense to any kind of bodily injury, including trauma or infection. Since this nonspecific immune response has a limited ability to recognize specific antigens, it generally reacts to most pathogens in the same manner. When the innate immune response fails to effectively combat invading pathogens, the body mounts an acquired immune response. Acquired immunity, however, involves a highly sophisticated recognition of foreign structures. This ability to learn to identify specific structures allows the body’s defenses to act quickly and efficiently in killing specific pathogens.

1.1 Host Defense Mechanisms

C. Innate immune response

D. Acquired immune response

1.1.2 Immune effector cells

A. T cells

1.1.3 Cytokines

TABLE 3-1 IMPORTANT INTERLEUKINS AND THEIR ACTIONS

CYTOKINE SOURCE ACTIONS
IL-1 Macrophages Stimulate cell activity or production of mediators in a variety of cells, including lymphocytes, macrophages, and endothelial cells. They also cause fever.
IL-2 Helper T cells Activate helper and cytotoxic T cells.
IL-3 Activated T cells Stimulate production of RBCs in bone marrow.
IL-4 Helper T cells Stimulate B cell growth and production of IgE and IgG.
IL-5 Helper T cells Stimulate B cell differentiation into plasma cells, activity of eosinophils, and production of IgA.

TABLE 3-2 IMPORTANT INTERFERONS AND THEIR ACTIONS

CYTOKINE SOURCE ACTIONS
INF-α Leukocytes Inhibit viral growth
INF-β Fibroblasts Inhibit viral growth
INF-γ Helper T cell Strong activator of macrophages, important in cell-mediated immunity

1.1.4 Complement System

1.1.5 Immunoglobulins (Antibodies)

1.2 Hypersensitivity

Hypersensitivity reactions are characterized by exaggerated immune responses that result in injury. There are four types of hypersensitivity reactions.

1.3 Immunopathology

2.0 GENERAL MICROBIOLOGY

2.1 Biology of Micro-Organisms

2.1.1 Bacteria

Jan 5, 2015 | Posted by in General Dentistry | Comments Off on 3: Microbiology and Pathology
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