immunology ver. 97

8/8/2019 Immunology Ver. 97

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Immune System

Constellation of responses to attacks from

outside the body.

Cell and proteins which protect body fromantigen. (viruses, bacteria, fungi )

Immunity the bodys ability to resist

infection.

Maintains homeostasis

Monitors degradation

Removal of damaged cells

Discovers and destroys abnormal cells


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Immune System

Antigen

Substance foreign to the body

Antibody (Immunoglobulins)

Molecule made by lymph tissue

Defends body against bacteria, viruses, or other

foreign bodies (antigens)

Each antibody reacts to a certain foreign body

Allergen substance that causes inappropriate

immune response (allergy)

Major Histocompatibility Complex Main Menu


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Formation, development, and specialization of all

functional blood cells

Back


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Cells of the Immune System

Cells destined to

become immunecells, like all blood

cells, arise in the

bone marrow from

so-called stem cells.


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T-Cells

T helper

A pertinent coordinator ofimmune regulation.

To augment or potentiateimmune responses byactivating other WBC.

T killer/suppressor

Directly killing certaintumor cells, viral-infectedcells and sometimesparasites.

also important in down-regulation of immuneresponses.


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Natural KillerCells

Effector cells that

directly kill certain

tumors such as

melanomas,

lymphomas and viral-infected cells, most

notably herpes and

cytomegalovirus-

infected cells.


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Granulocytes

composed of

neutrophils,

eosinophils andbasophils, based on

their staining

characteristics with

certain dyes. Important in the

removal of bacteria

and parasites from the

body.


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Macrophages

regulation of immune

responses.

Scavengers - pick upand ingest foreign

materials and present

these antigens to other

cells

Initiation of an immune

response


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Monocytes (2-6%) circulate in the blood

Macrophages found in body tissues Scavengers Secrete a wide variety of powerful

chemicals Activates T cells.

Phagocytes and Granulocytes


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Neutrophils (40-75%) Circulate in blood but move into tissues PRN Contain granules filled with potent chemicals Destroys microbes + key role in acute

inflammatory reactions.

Eosinophils(2-5%) Allergy, suppresses inflammation & helminthes

(parasitic worm) infection, Decrease granulocyte migration

Basophils(0.2-0.5%)

inflammatory mediator release Mast cells

granule-containing cells in tissue.


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Activation of B cells to make Antibody

AB Cell uses one of itsreceptors to bind to itsmatching antigen, which theB cell engulfs and

processes. The B cell then displays a

piece of the antigen, boundto a Class II MHC (majorhistocompatibility complex)protein, on the cell surface.

This whole complex thenbinds to an activated helperT cell to stimulates thetransformation of the B cellinto an antibody secreting

Plasma cell.


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Immunoglobulin

Immunoglobulin G / IgG (75%) Found in serum and tissue (instertitial fluid)

Assumes a major role in blood and tissue born

pathogen Activates complement system

Crosses the placenta

Immunoglobulin A / IgA (15%) Appears in the body fluid e.g. saliva, sweat,pulmo,

gastro, repro

Prevents absorption of antigen from food

Passes to neonates in breast milk


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Immunoglobulin

Immunoglobulin M / IgM (10%) Appears in the intravascular serum

First Ig produced in response to bacterial and viral

Activates the compliment system Immunoglobulin D / IgD (0.2%)

Appears in small amount serum

Influences B lymphocyte to differentiate

Immunoglobulin E / IgE (.004%) Appears in serum

Takes part in allergic and hypersensitivity reaction

Parasitic infection


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T - Cells T cells attacks and destroys

diseased cells they recognizeas foreign.

T lymphocytes are

responsible for cell-mediatedimmunity (or cellularimmunity).

T cells also orchestrate,regulate and coordinate theoverall immune response.

T cells depend on unique cellsurface molecules called theMajor HistocompatibilityComplex (MHC) to helpthem recognize antigenfragments


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T - Cells

Immature T cells (termed T Stem cells)

Migrate to the thymus gland in the neck, wherethey mature and differentiate into various types

of mature T cells. Killer T cell

Helper T cell

Suppressor T cell

Memory T cell

Produce substances called Cytokines

Interleukins which further stimulate the immuneresponse.


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T Cells - Types Cytotoxic orkillerT cells (CD8+)- do their work by releasing

lymphotoxins, which cause cell lysis

HelperT cells (CD4+) - serve as managers, directing the immune

response,

secrete chemicals called lymphokines that stimulate cytotoxic T cells

and B cells to grow and divide, attract neutrophils, and enhance the

ability of macrophages to engulf and destroy microbes

SuppressorT cells

a component of the immune system that suppress immune responses of

other cells.

These cells are involved in closing down immune responses after theyhave successfully tackled invading organisms and also in keeping in

check immune responses that may potentially attack one's own tissues

("autoimmunity").

Memory T cells - programmed to recognize and respond to a pathogen

once it has invaded and been repelled.


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Lymphatic System

The lymphatic system is a complex network

of lymphoid organs, lymph nodes, lymph

ducts, lymphatic tissues, lymph capillaries

and lymph vessels.

They produce and transport lymph fluid from

tissues to the circulatory system.

The lymphatic system is a major componentof the immune system.


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Lymphatic System Functions:

To collect and return interstitial fluid, including

plasma protein to the blood, and thus help

maintain fluid balance.

To defend the body against disease by

producing lymphocytes

To absorb lipids from the intestine and

transport them to the blood.


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Lymphoid Organs

Thymus Gland

Red Bone Marrow

Spleen Lymph nodes

Peyers Patches

Tonsils Adenoid

Vermiform Appendix


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Innate (natural Immunity) Provides a non specific response to invader

Basis is their ability to recognize self and non self

Natural mechanism

Includes Physical and chemical barriers (Normal Flora)

Skin Genitourinary

Respiratory

Muco cilliary action

Cell of the innate immune response

Inflamatory response

Complement response


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Inflammatory Response

The complex biological response of vasculartissues to harmful stimuli, such as pathogens,damaged cells, or irritants

Acute Inflammation initial response of the body to harmful stimuli

achieved by the increased movement of plasmaand leukocytes from the blood into the injured

tissues. cascade of biochemical events propagates and

matures the inflammatory response, involving thelocal vascular system, the immune system, andvarious cells within the injured tissue.


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Inflammatory Response

Chronic Inflammation

Prolonged inflammation

leads to a progressive shift in the type of cells

which are present at the site of inflammation andis characterized by simultaneous destruction and

healing of the tissue from the inflammatory

process.


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Causes ofAcute Inflammation Microbial infections

Hypersensitivity reactions

Physical agents Irritant and corrosive

chemicals

Tissue necrosis


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Five Cardinal Symptoms ofAcute

Inflammation

Redness (rubor)

Heat (calor)

Swelling (tumor) Pain (dolor)

Loss of Function


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Vasodilatation

CellularInjury

TemporaryVasoconstrictions

IncreasePermeability

Increase Bloodflow

Heat (Calor)

Redness (Rubor)

Plasma Leak intothe affected part

Swelling (Tumor)

Increase NervePressure

Pain (Dolor)LOSS OF

FUNCTION


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Histamine Causes vascular dilatationand the immediate transient

phase of increased vascular permeability

stored in mast cells, basophil and eosinophil leukocytes,

and platelets

Lysosomal

compounds

released from neutrophils

increase vascular permeability

Prostaglandins a group of long-chain fatty acids derived from arachidonicacid and synthesized by many cell types

prostaglandins potentiate the increase in vascular

permeability

Leukotrienes synthesized from arachidonic acid, especially in neutrophils,

and appear to have vasoactive properties

a mixture of leukotrienes is involved in type I hypersensitivity

5-

hydroxytryptamine

(serotonin)

a potent vasoconstrictor

present in high concentration in mast cells and platelets


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Plasma Factors

Complementsystem cascade system of enzymatic proteins activated

during inflammatory response

Coagulation system responsible for the conversion of soluble fibrinogen

into fibrin

activate the coagulation, kinin and fibrinolytic systems

Kinin system (stimulates pain receptors)

activated by coagulation factor Bradykinin is also a chemical mediator of pain

Fibrinolyticsystem Plasmin is responsible for the Iysis of fibrin into fibrin

degradation products


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Complement System Circulating Plasma proteins made in the liver

Activated when Antigen-antibody connects

It coats microbes with molecules that make them moresusceptible to engulfment by phagocytes

They also encourage polys to adhere to the walls of capillaries(margination) from which they can squeeze through in a matterof minutes to arrive at a damaged area

Emigration by squeezing of the wandering macrophagesthrough the capillary walls to the tissue

Extravasation also know as diapedesis

Once phagocytes do their job, they die and their "corpses,"pockets of damaged tissue, and fluid form pus.


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Immunity

Acquired

Passive Active

Natural Artificial Natural Artificial


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Types ofAcquired Immunity

Acquired Active Immunity (exposure)

The immunologic defenses are developed by the

persons own body in response to the presence of

antigens. Immunity last many years or even lifetime.

Acquired Passive Immunity (transferred)

Atemporary immunity transmitted from anothersource that has developed immunity.


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Acquired Active

Naturally Acquired Active

Exposure to different pathogens leads to

infections, which result in a protective immune

response against these pathogens.

Artificially Acquired Active

Vaccine used for active immunization consist of

live (attenuated) organism, killed whole organism,

microbial components or secreted toxin.


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Acquired Passive

Naturally Acquired Passive

Immunity is transferred form mother to fetus

through placental transfer of IgG or colostral

transfer of IgA.

Artificially Acquired Passive

Artificially transferred by injection of gamma

globulins from other individual or gamma globulins

from an immune animal.


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PhagocyticHumoral

Cellular

Stages of Immune Response

RecognitionProliferation

Response

Effector


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Phagocytosis

Involves WBC and Macrophages

Has the ability to ingest foreign matter

They also responsible for removing bodys dead

cell Cell in the necrotic tissue release a substance that

cause inflamatory response

Apoptisis programmed death cell

Main Menu


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Antigen Recognition

The mechanism by which the B

lymphocytes recognize the invading antigen

and respond by producing antibodies.


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Role ofAntibodies Defend against foreign

invaders in several ways.

Agglutination bind orclumping together of antigenand antibody that helps clear

the body of the invadingorganism by facilitatingphagocytosis.

Opsonization coating stickysubstances that facilitatesphagocytosis.

Each antibody moleculeconsist of two subunits, eachof which contains a light and aheavy peptide chain.


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Antigen Antibody Binding

Antigenic Determinant

The portion of the

antigen involve in

binding with theantibody.

Lock-and-key situation

The binding of the Fab

fragment (antibody-

binding site) to the

antigenic determinant.


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Cell Mediated Immunity

CD - stands forCluster ofDifferentiation

(CD8+ is read "CD8 positive)

The large number of molecules on the surfaces

of lymphocytes allows huge variability in theforms of the receptors

They are produced with random configurations

on their surfaces


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I. Recognition StageII. Proliferation Stage

III. Response Stage

IV. Effector Stage


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I. Recognition Stage

Recognize

invaders as foreign

Presentation to themacrophages

Macrophages plays

an important role in

processing theantigen


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II. Proliferation Stage

The dormant lymphocytes proliferate and

differentiate into cytotoxic (killer) T Cells or

B Cells responsible for formation and

release of antibodies


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III. Response Stage

The cytotoxic T cell and the B Cell

perform cellular and humoral function

respectively.


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IV. Effector Stage

Antigens are destroyed or neutralized

through the action of antibodies, complement,

macrophages and cytotoxic T Cells.


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HISTORY

Age

Life style

Nutrition Recent exposure to pathogen

Drug intake

immunization

History of immune disorder


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Respiratory

Changes in respiratory rate

Cough (dry or productive)

Abnormal lung sounds

Rhinitis

Hyperventilation

Bronchospasm


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Cardiovascular

Hypotension

Tachycardia

DysrhytmiaVasculitis

Anemia


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Genitourinary

Frequency and burning on urination

Hematuria

Discharge


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Gastrointestinal

Hepatosplenomegally

Colitis

Vomiting Diarrhea


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Skin

Rashes

Lesion

Dermatitis

Hematoma or purpura

Edema or urticaria

Inflammation

Discharge


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Neurosensory

Cognitive dysfunction

Hearing loss

Visual design

Headaches and migraine

Ataxia

Tetany

Main Menu


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Leukocyte and Lymphocyte Tests

Humoral (Antibody Mediated) Immunity Test

Cellular (Cell Mediated) Immunity Test

Phagocytic Cell Function TestComplement Component Test

Hypersensitivity Test

HIV Infection Test


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Overview

Caused by an oversensitive immune system

An allergic reaction is when the immune

system reacts to substances (allergens) that

are generally harmless and in most people donot cause an immune response.


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In a person with allergies, the first exposure

to the allergen triggers the immune system to

recognize the substance. Succeeding exposure will usually result in

symptoms.


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When an allergen enters the body of aperson with a sensitized immune system,

histamine and other chemicals are released

by certain cells. This causes itching, swelling, mucus

production, muscle spasms, hives,

rashes, and other symptoms.

Symptoms vary in severity from person to

person.


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Some disorders may be associated withallergies. These include eczemaandasthma, among others.

Commonallergens include those that

contact the skin, breathing passages, orthe surface of the eye (such as pollen; seealso allergy to mold, dander, dust).

Food allergies and drugallergies are

common. Allergic reactions can be caused by insect

bites, jewelry, cosmetics, and almost anysubstance that contacts the body.


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Signs & Symptoms

runny nose

tearing eyes, burningor itching eyes

red eyes,conjunctivitis

swollen eyes

itching nose, mouth,throat, skin, or anyother area

wheezing

coughing

difficulty breathing hives (skin wheals)

skin rashes

stomach cramps

vomiting diarrhea

headache


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Prevention

Children who have been breastfed areless likely to have allergies.

There is also evidence that infants

exposed to certain airborne allergens(such as dust mites and cat dander) maybe less likely to develop related allergies.

Once allergies have developed, treatingthe allergies and carefully avoiding thosethings that cause reactions can preventallergies in the future.


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HYPERSENSITIVITY REACTIONS

Are immune responses to allergens that result in

tissue destruction

Type I (ANAPHYLACTIC) reactions.

Anaphylaxis is an acute, life-threatening allergicreaction marked by rapidly progressive urticaria

& respiratory distress which may result in

anaphylactic shock.

ETIOLOGY. Results from ingesting or systemicexposure to allergenic substances (drugs, foods,

insect-venom)


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PATHOPHYSIOLOGY

Exposure to allergen

Production of IgE binds to mast cells & basophils

Reexposure IgE reacts immediately to the allergen

Release of potent chemicals mediators (histamine, ECF-A)

Ig G or IgM releases 2 other chemical mediators

(bradykinin & leukotrienes)Profound vascular changes

Vascular collapse ANAPHYLACTIC SHOCK


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ASSESSMENT FINDINGS

LOCA

L EFFECTS wheals with surroundingred flares & urticaria

SYSTEMIC MANIFESTATIONS.

Intense urticaria and edema at the site of

injection rapidly spreading in the face, handsand other body areas

Respiratory distress from bonchospasm,

coughing, sneezing or wheezing Arrhythmias, tachycardia, or bradycardia,

hypotension & signs of circulatory collapse


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NURSING MANAGEMENT

Establish patent airway Administer epinephrine, IM or SQ to constrict

blood vessels, raise RR, improve myocardialcontractility

Establish patent IV line for fluid administration Oxygen therapy

Administer prescribed medications (anti-

histamine, bronchodilators, vasopressors,corticosteroids)

Teach preventive measures

Maintain safety precautions


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Type II (CYTOTOXIC) reactions are

mediated by Ig G and IgM, which attach tocells (usually circulating blood elements)and cause cell lysis. Ex. Hemolytic anemia

Type III (IMMUNE COMPLEX) reaction are mediated by antigen-antibodycomplexes that deposit in the lining ofblood vessels or on tissue surfaces ex.

Rheumatoid arthritis, serum sickness Type IV (DELAYED HYPERSENSITIVITY)

reactions are mediated by lymphokinesreleased from sensitized lymphocytes


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AIDS

Acquired immunodeficiency syndrome

Collection of symptoms and infectionsresulting from the specific damage to theimmune system caused by infection with thehuman immunodeficiency virus (HIV) whichallows normally benign organisms to flourishand cause disease.

The virus causes cell death and a decline in

immune function resulting in opportunistic

infections, malignancies & neurologic

problems


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Anatomy of the HIVVirus

Gp120 Envelope Protein

Gp41 Envelope Protein

P17 matrix protein

P24 Capsule Protein

Reverse Transcriptase

The Lipid Membrane


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Anatomy of the HIVVirus HIV Human Immuno Virus

AIDS

CD4 count is


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Etiology

Risk factor

Unprotected vaginal, anal. Or oral intercourse

IV drug used with contaminated needles

HIV infected mother to child in utero (Vertical

Transmission)

Contaminated needle stick

Blood and blood product recipient

Semen used forAI (artificial insemination)


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PATHOPHYSIOLOGYHIV (Retrovirus)

Carries genetic information as RNA

Attach to surface antigen (CD4)

Transmits genetic information into the human cell

Primary cells affected are the Helper T cells

Direct infiltration into the CNS

HIV RNA enters the cell, reverse transcriptase converts RNA

to DNA (deoxyribonucleic acid) material

As DNA, the virus is able to replicate as the cell replicate

Rapid cell destruction & proliferation can occur

Virus can lie dormant for approx.10

years


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Stages of HIVdisease

Primary Infection (Acute HIV)

Period from infections with HIV to the

development of antibodies to HIV

Viremia stage Severe-flu like symptoms

Window period

Test negative with HIV antibody test

Viral set point Balance between HIV and immune response


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HIV asymptomatic

CD4 is > 500

Feeling well

HIV symptomatic

CD4 is 200-499

Gradual falling of CD4

AIDS


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Symptoms

Flu-like symptoms

No symptoms (asymptomatic)

Fever, Fatigue, Diarrhea, Skin Rashes,

Night Sweats, Loss of appetite,lymphadenopathy (enlarge lymph nodes)


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Opportunistic Infections

Pneumocystis Carinii Pneumonia

Cryptococcal Meningitis

Toxoplasmosis

Candidiasis Histoplasmosis

Cytomegaloviris infection

Tuberculosis

Kaposis sarcoma, anA

IDS related lymphoma Neurologic deficit (AIDS dementia) characterized by

behavioral, cognitive and motor deterioration

Problems with other organs; lungs, liver, kidneys,

intestines, and heart.

LABORATORYAND DIAGNOSTIC


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LABORATORYANDDIAGNOSTIC

STUDY

ELIZA (enzyme linked immunosorbent assay) Diagnostics.

Identifies antibodies directed specifically against HIV.

Western Blot Assay

To confirm HIV antibodies

Viral Load

Measures HIV RNA in the plasma

Better predictor of the risk of HIV progression than CD4

CD4 count, CD4/CD8 ratio

Significantly lowering of CD4 over CD8

Ora Quick Rapid HIV 1Antibody Test

Detects antibodies to HIV 1


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Complications:

HIV Encephalopathy

AIDS dementia complex

Progressive decline in cognitive, behavioral, and motor

functions

Wasting syndrome

Profound involuntary wt loss exceeding 10% of baseline

body weight.

Either theres a presence of chronic diarrhea for more

than 30 days or chronic weakness with documentedfever


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Kaposis Sarcoma

tumor caused by Human herpesvirus 8(HHV8)

KS lesions are nodules or blotches that

may be red, purple, brown, or black, andare usually papular(ie palpable or raised).

Can lead to venous stasis, lymphedema(fluid retention)

Skin lesion increase discomfort andinfection

Death may result from tumor progression


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NURSING MANAGEMENT Administer prescribed medications

- Includes antibiotics for HIV-related infections,antiretroviral therapy, antidiarrheals and antiemetics

Promote preventive measures related to thetransmission of HIV

Promote public education regarding HIV & AIDS(teach clients & families to practice safe sex, avoidsharing needles, avoid touching anothers body fluidwithout protection)

Maintain skin integrity

Instruct the client to avoid scratching, strongperfumed soaps and adhesive tapes


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NURSING MANAGEMENT

Help maintain nutritional status- By controlling nausea & vomiting

- Encourage foods that are easy to swallow

- Encouraging oral hygiene before and after meals

- Promoting a high-protein, high-calorie diet

- Monitoring weight, intake & output

- Monitoring fluid & electrolyte balance

- Administering appetite stimulants

Teach ways to cope with chronic illness to

the client & significant others.


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NURSING MANAGEMENT Promote infection prevention

- Discuss importance of personal hygiene, keepingbathrooms and kitchens clean

- Avoid exposure to individuals who are sick,avoiding smoking and alcohol

- Adequate rest, activity and a well-balanced diet

Discuss ways the client and family canassist with mental status problems.

These includes putting notes on note boards,using calendar and clocks to orient the client totime & place.


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Terminologies

Infection

The invasion and multiplication of microorganism

in the body tissue that result in cellular injury.


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Terminologies contd Microorganism

Infectious agent

Pathogen

Microorganism that causes a disease

Pathogenicity The ability of the microorganism to produce a disease

Virulence

The degree of pathogenicity

Sepsis

The state of infection Asepsis

The freedom from disease causing microorganism


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InfectiousA

gentReservoir

Portal of Exit from Reservoir

Mode of Transmission

Portal of Entry to the Susceptible Host

Susceptible Host


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immunology ver. 97

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