NURS 301 Test 3 Study Guide
Ch 14: Immunology
Immunity Is
Organized series of actions by the body in order to protect itself against a pathological
organism resulting in destruction or neutralization of the organism
Immunity= A state of responsiveness to foreign substances such as microorganisms and tumor
proteins
Functions of the Immune System
1. Homeostasis- recognize and destroy damaged cells; damaged cells are digested and
removed
2. Defense- Protect against antigens
3. Surveillance- Destroy damaged (mutated) cells; don’t destroy good tissue
Foreign Substances (Antigens)
Bacteira, viruses, fungi, prions, parasites
Haptens vs Antigens
1. Antigen= Anything that triggers an immune response
2. Hapten= “signature” of the antigen
Antigens have protein markers that allow body to attack them with right machine
Properties of Immune Response
Specificity- when foreign substance enters body, cellular changes occur. Form antibodies on
lymphocytes
Memory- Allows for quicker response to antigen for subsequent exposures
Self recognition- immune system’s ability to recognize self vs non-self
o If body is unable to recognize self, antibodies against self lead to tissue destruction
o Self recognition prevents auto-immune disorders
Self limitation- once antigen is removed, the response decreases to prevent damage to body’s
own cells
Specialization- different organisms and foreign material are attacked in the correct way to stop
them
Cells Involved with Immune System (The Major Players)
Mononuclear Phagocytes= Monocytes and macrophages engulf pathogens and take it to the
right response system based on surface proteins
o Humoral- attacked by B lymphocytes
o Cell Mediated- attacked by T lymphocytes
Lymphocytes:(produced in bone marrow, then differentiate into B and T cells)
1. B Lymphocytes- differentiate into plasma cells when activated which produce antibodies
(immunoglobulins)
2. T Lymphocytes
a) T cytotoxic cells (CD8) Cell mediated; attack the antigen
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b) T helper cells (CD4) Cell mediated and Humoral
3. Natural Killer Cells- cell mediated; no prior sensitization required. Immune surveillance
for malignant cell changes
Dendritic Cells- activate cell mediated response
Cytokines- messengers between cell types
Two Types (Ways) of Immunity
1. Innate Immunity
a) Natural Innate Immunity
▪ Exists w/o former contact with antigen
▪ “Born with it” (human specific immunity)
▪ Includes natural barriers (skin, mucous membranes) and inflammatory response
▪ Primary role= First Line Defense
▪ Neutrophils & NKC’s remove anything “abnormal;” no specificity! Just engulf and
remove
2. Acquired Immunity
a) Active Acquired Immunity
▪ Occurs when body responds to the presence of pathologic organism and produces
antibodies against them
▪ Comes FOLLOWING an invasion and results in sensitized antibodies
▪ When reinvaded by organism, response is faster!
▪ Can take a while to develop, but lasts a long time
▪ Invaded, then reinvaded! The army is already built up!
▪ Examples of Artificial Active Acquired:
• Vaccine- body produces antibodies because of immunization/inoculation
• Tetanus Vaccine
▪ Examples of Natural Active Acquired:
• Disease- body produces antibodies because of pathogen
• Getting chicken pox from your cousin
b) Passive Acquired Immunity
▪ Temporary!
▪ Receives antibodies to antigen “passively” instead of making them
▪ Quick and strong, but it doesn’t last long! Temporary because there are no memory
cells specific to antigen
▪ May or may not have prior exposure
▪ Comes from someone else! Either mother or a nurse
▪ Examples of Artificial Passive Acquired:
• Injection of gamma-globulins (serum antibodies)
• Rabies immunoglobulin injection
▪ Examples of Natural Passive Acquired:
• Immunoglobulin from mother to fetus via placenta
Types of Immune Response
• Each has unique properties and actions based on antigens involved; both form antibodies!
Humoral Immunity- Think “Bacteria” (also extracellular viruses)
o The antigen that invades causes B-cells to divide and become plasma cells (differentiated
B-cells) which produce antibodies (immunoglobulin) that travel in the bloodstream to
communicate with other cells
o B lymphocytes produce:
1. Antibodies
2. Memory cells
o “Humor” is Latin word for “liquid”
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o **Primary Immune Response takes 4-8 days after initial exposure
o **Secondary Immune Response takes 1-3 days; it is stronger and longer lasting!
o Cells Involved
o B-lymphocytes
o Products
o Antibodies (Immunoglobulins)
o Memory Cells:
o **Present
o Protection
o Bacteria
o Extracellular viruses
o Respiratory and GI pathogens
Cell-Mediated Immunity- Think “Viruses”
o When T-cells recognize antigen and start immune response
o Production of sensitized T-Lymphocytes to kill and destroy pathologic organisms
o Does NOT deal with bacteria! Only INTRACELLULAR VIRUSES such as HIV
Exception: Few mycobacteriums that have to live within cell are the only bacteria
attacked by cell mediated
o Primary Uses:
Protection primarily against cancer cells, virus-infected cells, and fungal infections
**Rejection of transplanted tissue**
Contact hypersensitivity reactions
Tumor Immunity
o Cells Involved
1. T-lymphocytes (CD4 Helper and CD8 Cytotoxic)
2. Macrophages
3. NK cells
o Products
Sensitized T cells
Cytokines
o Memory Cells:
**Present
o Protection
Funguses
Intracellular viruses
Chronic infectious agents
Tumor cells
Immunological Effects of Aging
• Decreased immune system function (immunosenescence)
• Increased susceptibility to infection
• Decreased number of T cells
• Increased incidence of tumors (primary clinical evidence is high incidence of malignancy!)
• Immunity because of vaccines may not be as strong
• Immunological escape becomes more opportunistic
Altered Immune Response
• Overacting Immune Response (Hypersensitivity Reactions)
o Over reactive against antigens
o Can’t practice self limitation
o Four Classifications:
▪ Type I: IgE Mediated (most common; “allergies”)
▪ Type II: Cytotoxic Reaction (blood transfusion)
▪ Type III: Immune-Complex Reaction
▪ Type IV: Delayed Hypersensitivity Reaction (transplant reaction)
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o Examples:
▪ Allergies
▪ Autoimmune disease (attacks self)
• Under Responsive Immune System
o Severe infections
o Immunodeficiency diseases
o Malignancies
o Patients on Chemo
Type I IgE Mediated Reaction
• Chemical mediators released from Mast Cells:
o Histamine, serotonin, leukotriene, eosinophil chemotactic factor, kinins, bradykinin
• Symptoms associated with Type I:
o Increased mucosal secretions, itching, increased vascular permeability
o Response of IgE can range from sniffles to anaphylaxis!
• **Know that IgE response is r/t allergies!
o IgE attaches to mast cells (which contain histamine) for transportation, then they attach to
antigen and mast cell explodes! All the histamine is released!
• Anaphylaxis- Medical Emergency!
o Shock can occur d/t kinins (Bradykinin) decreasing BP
o Treatment:
▪ Epinephrine
▪ Maintain Airway and oxygen support… ALWAYS first think airway!!!
• Smooth muscle is clamping down on airway
• Intubation is the best rapid response to keep airway open
▪ Vital signs
▪ Maintain circulatory volume and BP
▪ Keep warm; other drugs
Type II Cytotoxic (IgG or IgM) Reaction
• Target cells (those destroyed during type II reaction) are usually RBCs, WBCs, and platelets
• Commonly antigens involved are ABO blood group, Rh factor, and drugs
• Associated with Blood Transfusion Reaction!
o Instant reaction; no delay!
o Altered airway leads to stridor
o Febrile, anxious, SOB
• If a patient is transfused with incompatible blood:
o Antibodies immediately coat the foreign RBC’s
o RBC’s agglutinate (clump)
o Life threatening! Cellular lysis and possible renal failure secondary to hemaglobinuria
o First Thing: STOP the transfusion! Then, protect airway
Collaborative Care of Hypersensitivity Reactions
• After allergy is diagnosed,
o **Most Important: Avoid triggers/allergens!
o Treat symptoms
o If needed, desensitization through immunotherapy (allergy shots)
• Document allergies
• Drug therapy
Drug Therapy for Chronic Allergies
• Antihistamines- Best to treat allergic rhinitis and urticaria
• Sympathomimetic/Decongestant Drugs