Download Chapter 14 Immunity, Infection Lewis

Immunology
Chapter 14
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Normal Immune Response
• Immunity
• Is the body’s ability to resist disease
• Serves three functions
• Defense
• Homeostasis
• Surveillance
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Types of Immunity
• Innate
• Present at birth
• First-line defense against pathogens
• Acquired
• Developed immunity
• Active
• Passive
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Vaccines
• Active immunity occurs either naturally or
through vaccine administration.
• Live or attenuated
• Killed or inactivated toxins
• Human immune globulin
• Animal serum or antitoxins
• Under-served children may not receive
vaccines. Why?
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Normal Immune Response
• Antigens
• Substances the body recognizes as
foreign that elicit an immune response
• Most are composed of protein.
• Antibodies
• Immune globulins produced by
lymphocytes in response to antigens
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Organs of Immunity
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Normal Immune Response
Lymphoid Organs
• Central (primary) lymphoid organs
• Thymus gland
• Thymus gland shrinks with age.
• Involved in the differentiation and maturation
of T lymphocytes
• Bone marrow
• Produces red blood cells, white blood cells,
and platelets
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Normal Immune Response
Lymphoid Organs
• Peripheral lymphoid organs
• Lymph nodes
• Tonsils
• Spleen
• Lymphoid tissues associated with the gut,
genitals, bronchi, and skin
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Normal Immune System
Cells of Immune Response
• Mononuclear phagocytes
• Include monocytes in the blood and
macrophages found throughout the body
• Capture, process, and present antigens to
lymphocytes to initiate an immune
response
• Capture antigens by phagocytosis
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Normal Immune System
Cells of Immune Response
• Lymphocytes
• Produced in the bone marrow
• Eventually migrate to peripheral organs
• Differentiate into B and T lymphocytes
• T Cytotoxic cells
• T Helper cells
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Types of Lymphocytes
T cells
B cells
Natural killer (NK) cells
70%–80%
10%–20%
<10%
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Normal Immune Response
Cytokines
• Tumor necrosis factor (TNF)
• Activates macrophages and granulocytes
• Promotes the immune and inflammatory
responses
• Kills tumor cells
• Responsible for extensive weight loss
• Associated with chronic inflammation and
cancer
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Normal Immune Response
Comparison of
Humoral and Cell-Mediated Immunity
Humoral
Cells involved B lymphocytes
Products
Antibodies
Memory cells
Present
Cellular
• T lymphocytes
• Macrophages
• Sensitized T cells
• Cytokines
Present
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14
Normal Immune Response
Comparison of
Humoral and Cell-Mediated Immunity
Humoral
Protection • Bacteria
• Viruses
(extracellular)
• Respiratory
pathogens
• Gastrointestinal
pathogens
Cellular
• Fungus
• Viruses
(intracellular)
• Chronic infectious
agents
• Tumor cells
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15
Normal Immune Response
Humoral Immunity
• Antibody-mediated immunity
• Antibodies produced by plasma cells
(differentiated B lymphocytes)
• Primary immune response is evident
4 to 8 days after initial exposure to
antigen.
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Normal Immune Response
Humoral Immunity
• Five classes of immune globulins
• Each has specific characteristics
• IgG
• lgA
• lgM
• lgD
• lgE
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Normal Immune Response
Humoral Immunity
• When an individual is exposed to an
antigen for a second time, the
response is faster (1 to 3 days) and
lasts longer.
• Main product of secondary response is IgG
rather than IgM.
• Memory cells account for more rapid
production of IgG.
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Primary and Secondary Immune
Response
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Normal Immune Response
Cell-Mediated Immunity
• Immune responses initiated through
specific antigen recognition by T cells
• Several cell types involved in cellmediated immunity
• T lymphocytes
• Macrophages
• NK cells
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Normal Immune Response
Cell-Mediated Immunity
• Important roles
• Immunity against pathogens that survive
inside cells (viruses, some bacteria)
• Fungal infections
• Rejection of transplanted tissues
• Contact hypersensitivity reactions
• Tumor immunity
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Infections
• Localized – limited to a small area
• Disseminated- spreads beyond site of
infection
• Systemic- spread throughout the body
(sepsis)
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imprint of Elsevier Inc.
Infections
• Bacterial
• E Coli, normal in intestine only
• Virus
• Influenza
• Fungal
• Similar to plants , think mushrooms
• Candida
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Infections
• Emerging infections- infectious diseases
that have recently increased or threatens to
increase in near future.
• Ebola
• Lyme
• Herpes types 6 & 8
• Hanta
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Infections
• Reemerging infections- infections once
thought gone but now reemerging
• Diptheria
• Pertussis (whooping cough)
• TB
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Antibiotic Resistant Organisms
• Methicillin Resistant Staphylococcus
Aureus (MRSA)
• Vancomycin Resistant Enterococcus
(VRE, more virulent than MRSA)
Streptococcus Pneumonia
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Antibiotic Resistant Organisms
• HCP have contributed to this
• Antbx for viral infections
• Prescribing pts antbx for unnecessary
reasons
• Inadequate drug regimens ( 7 vs 10-14
days)
• Using broad spectrum antbx instead of 1st
line antbx
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imprint of Elsevier Inc.
Antibiotic Resistant Organisms
• Pts contribute to this by:
• Skipping doses
• Not taking antbx for full duration of
therapy
• Saving unused antbx for “later, just in
case”
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imprint of Elsevier Inc.
Infection Prevention
• OSHA – Occupational Safety & Health
Administration is a federal agency that
protects workers from injury or illness
in places of employment
• Employee MUST be provided with
appropriate PPE and safety equipment
• Ebola - THR - 2014
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imprint of Elsevier Inc.
Infection Prevention
• HAI- Healthcare Associated Infections
(Nosocomial infections)
Risks to ptsActions to reduce these risksPPE and HANDWASHING, foam, sanitizer
Most susceptible are hospitalized pts
and immunosupressed
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Precautions
• Standard or universal – for all pts
• Isolation:
• Airborne- infection suspended in air
• Droplet- through air or respiratory system
• Contact- through direct and indirect
contact
Boxes, carts and signs on door for how to
dress before entering pt room
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imprint of Elsevier Inc.