Acute and Chronic Immunity Lawton, ok

A normally functioning immune system does what?

1. Provides continuous surveillance 2. Protects body from invading organisms. 3. Maintains homeostasis. 4. Discovers and disposes of abnormal cells.

Types of T cells

1. T helper cells. 2. T cytotoxic cells. 3. T suppressor cells.

Hyperemia:

Increased blood flow to the area.

Four stages of the infectious process?

Incubation period Prodromal phase Acute Illness Convalescent stage

Inflammation vs infection

Inflammation is always present with infection, but infection is NOT always present with inflammation.

Types if Cytokines:

Interleukins Interferon Tumor Necrosis Factor (TNF) Colony-Stimulation Factors (CSFs)

Interleukins:

Interleukins—produced by lymphocytes and enable cells of immune system to communicate and coordinate immune response. Stimulate chemical factors that begin the inflammatory response.

Hypertrophic scars

Large, red, raised and hard; body produces excess collagen tissue.

Obesity effect on infection

Obesity can lead to a depressed immune system. It can affect the ability of WBCs to multiply and rush to the site of an infection, and inhibits B cell production of antibodies. It has also been found to inhibit T cell and dendritic cell responsiveness.

Dehiscence

Seperation and disruption of the previously joined wound edges; healing site bursts

The nature of infection

invasion of the body by pathogens which can cause disease. Disease occurs if pathogens multiply and cause destruction of normal tissue.

Infection

is caused by invasion of cells and tissues by a pathogen (bacteria, fungi, virus). An infection is present when the invading agent is living, growing, and multiplying in tissues. It is able to overcome the body's normal defenses. With an infection, you will see greater systemic manifestations.

Inflammation

is part of the normal healing process when cells are injured. It can be caused by pathogens, BUT can also be caused by nonliving agents, such as heat, radiation, allergens, and trauma. It is a defensive function intended to neutralize, control, or eliminate the offending agent to prepare the site for repair.

Elevation

reduces edema in injured extremity and ↑s venous return; reduces pain and improves circulation.

IgM

responsible for primary immune response; forms antibodies to ABO blood antigens; stimulates complement system, leading to cell-mediated immunity.

Colony-Stimulating Factors:

romote the production of WBCs. 3 main types: Granulocyte CSFs, Granulocyte-macrophage CSFs, Macrophage CSF.

Dendritic cells are found in?

skin, nose, lungs, stomach, and intestines; also found in the blood in an immature form.

Ice (cold)

used with initial vasoconstriction— ↓s swelling and pain. Heat is used after 24 hours— promotes healing by ↑ing circulation to the area, thus removing debris.

Primary cells of the immune system?

B cells and T cells.

Airborne

(RSV virus in children) suspended on dust particles.

Nutrition should be high in following to facilitate immunocompetence and wound healing:

* Protein: To correct negative nitrogen balance and promote synthesis of immune factors, leukocytes, fibroblasts, and collagen. * Carbs: for increased metabolic rate associated with inflammation and healing. *Moderate to low fat: for synthesis of fatty acids and triglcerides- important for cell membrane integrity. * Vit C: for Capillary synthesis, collagen formation, and resistance to infection. *Vit A: aids in the process of epithelialization, inc collagen synthesis, and tensile strength of the healing wound. *B-Complex: important for protein, fat, an carbohydrate metabolism. *Zinc: Promotes the wound healing and resistance to infection. * Malnutrition and poor nutrition will dec. the immune response and the number and function of T cells. Maintain fluid status: fluids are lost with fever, exudate formation and inc. metabolic rate.

Neutrophils, Monocytes, Macrophages.

**Neutrophils, Monocytes, Macrophages are types of WBCs (leukocytes). *Monocytes are circulating (in blood stream) precursors to Macrophages...when they enter various organs or tissues, they transform into Macrophages. **Macrophages-responsible for phagocytosis of inflammatory debris -capture, process, and present the antigen to the lymphocytes.....this triggers the immune response. **critical effectors and regulators of inflammation, and important components of the innate or natural immune response. This response acts within hours of a pathogen's appearance in the body. Innate defenses are nonspecific - they recognize and respond to any pathogen in a generic way. They include your first and second lines of defense against pathogens.

Bad about fever

*>104 can be damaging to body cells, and delirium and seizures can occur. *>105.5- damage occurs to internal structurs of many cells including those in the brain. Use antipyretics and or cooling blanket

Dendritic Cells:

*Capture antigens and transport them to their specific T cell....making dendritic cells important in the development of cell-mediated memory. *Help stimulate B cell memory, to a lesser extent. *Essential for the establishment and maintenance of immune tolerance—the ability of the immune system to tolerate all "self antigens" while retaining the ability to mount an immune response to "non-self antigens. * If immune tolerance fails, a person will develop an autoimmune disease. *Have a critical role in acquired (also called adaptive) immunity—especially cell-mediated immune response. Acquired immune response occurs with the third line of defense and involves the invasion of the body with an antigen, and the development of antibodies and sensitized lymphocytes. * Therefore essential for long term immunity.

To thrive, organisms need a proper environment to grow and multiply. They Need:

*Food or nourishment. *O2 or lack of it. *H2O (moisture) except for the spore formers (c-dif, salmonella). *Ideal temperature without extremes. *pH range of 5 - 8. *Minimal light; prefer darkness

If neutropenic?

*Protect mucous membranes (sponge sticks or rinse mouth instead of brushing teeth). *Eliminate fresh fruits and raw vegetables (may be heavily contaminated with microorganisms from the soil). *Keep fresh flower arrangements out of room. *Avoid contact with people who have been vaccinated with live viruses.

Interferon

*proteins produced by T cells when the invading organism is a virus. *Enhances the activity of macrophages, NK cells, and cytotoxic T cells; attacks certain tumor cells and viruses.

Role of Cytokines

*proteins produced by WBCs and lymphocytes when an antigen is detected.....over 100 different types. *interact with cells of the immune system to regulate the body's response to disease and infection— act as messengers between cells (T, B, monocytes, neutrophils) and instruct them to alter their proliferation, differentiation, secretion, or activity. *Initiate chemotaxis—the movement WBCs to an area of inflammation. Chemotactic Cytokines are produced locally at the site of injury and are responsible for moving neutrophils and monocytes to the area.!!!!! *mediate the normal inflammatory response and contribute to the manifestations seen with inflammation (such as fever).

Anti-inflammatory drugs

-Salicylates and NSAIDs inhibit PG synthesis. -Corticosteroids—inhibit PGs and leukotrienes thus reducing swelling and other symptoms of inflammation.

Antipyretics

-Salicylates and acetaminophen—lower temperature by action on heat-regulating center in hypothalamus. -NSAIDs-inhibit PG synthesis.

Lymph nodes 2 important functions:

1. Filter, remove and destroy antigens circulating in the blood and lymph. 2. Provide specific immune responses such as protection and continuous surveillance (contain b, t and other immune cells)

An abnormally functioning immune system does what?

1. Immune hyperactivity leads to allergic states. 2. Immunodeficiency causes exaggerated vulnerability to infections (HIV or cancer) (mild cold or viruses can kill) 3. Misdirected immune response results in autoimmune disorder (lupus, rheumatoid arthritis) 4. Failure of surveillance allows uncontrolled growth of tumor cells.

Circulating antibodies contibute to immunity in 3 ways:

1. bind to and coat complemetary antigen, making the antigen an easier target for destruction by macrophages and other cells. 2. Bind to the antigens and prevent them from entering or damaging other cells. 3. Trigger destruction of antigens by stimulating other immune responses, such as the complement pathway.

Hematopoiesis:

A process that forms the bone marrows stem cells. Stem cells are the source of all blood cells including: RBC, WBC, Platelets and Lymphocytes (B and T cells.)

T Helper cell role:

Activate many immune cells, including B cell and other T cells.. Regulate humoral (Body Fluid) and cell-mediated immunity.

Host environment:

Allows an organism to survive or not. Some humans are more susceptible than others. Host response is influenced by the organism's...... Host susceptibility.

Memory B cells

Are activated with B cells initial exposure to an antigen. They are encoded with the memory of the battle. They remain in circulation system for long periods of time. This is called the Secondary Immune Response. Protection against re-exposure.

Convalescent stage

As the infection is contained by the body's defenses and controlled by treatment (antibiotics, if bacterial), the person enters a convalescent stage. During this stage, the damaged tissues begin to heal and symptoms resolve.

T Cytotoxic Cells:

Attack antigens on cell membrane of foreign pathogens, release substances that destroy the pathogen- These cells are antigen specific and can be sensitized by exposure to the antigen. Often referred to as "Killer T Cells" b/c they directly kill virally infected cells, tumors, or foreign grafts.

Adhesions

Bands of scar tissue between or around organs; may lead to obstruction. Major organ dysfunction can occur.

Central Lymphoid Organs:

Bone Marrow and Thymus: both play a role in developing the primary cells of the immune system: B and T cells.

Where do B cells achieve immunocompetence?

Bone marrow

Afferent Lymphatic Vessels

Carry lymph and bacteria into sub capsular sinus of lymph node. Flows through cortical sinuses and medullary sinuses. Phagocytic cells in deep cortex and medullary sinuses attack the antigen.

Immune system 2 branched of special structures:

Central lymphoid Organs: Bone marrow, thymus. Peripheral lymphoid organs: Lymph nodes, spleen, tonsils, adenoids, appendix.

Thymus

Central lymphoid organ. Located in the mediastinum. Peak in childhood then atrophy. Aids in maintenance of T lymphocytes. 70-80% lymphocytes are T cells.

Contractures

Excessive fibrous tissue formation resulting in deformity.

Keloid scars

Extend beyond the wound edge- large tumor-like masses

Immune systems Three basic defense strategies:

First Line of Defense Second Line of Defense Third Line of defense

Skin Desquamation

First line of defense: Normal cell turnover.

What falls under teaching infection prevention and control?

Help with resources to stop bad habits, such as smoking, illicit drug, or excessive alcohol use—if there is a problem

Efferent Lymph vessels:

How cleansed lymphs leave the nodes. These vessels drain into specific lymph node chains that then drain into large lymph vessels that empty into subclavian vein of the vascular system.

Most common reservoir? and others?

Human body.Animals, food, water, soil, insects, inanimate objects (fomites), can also be reservoirs.

Contagious?

If it can be transmitted.

B cells

Immunocompetent B cells circulate in the blood and lymphatic system performing surveillance. On the surface are receptors that enable them to recognize antigens. They are very specific. When B cells encounter their specific antigen that attach to it!

Two categories on infection:

Localized in a small area. Systemic is widespread throughout the body.

Specialized cells:

Lymphocytes: B cells, T cells, Natural killer cells. Leukocytes: Neutrophils, macrophages, dendritic cells.

Natural Killer Cells:

Lymphocytes: Not T or B cells, but large lymphocytes with numerous granules in the cytoplasm - involved in recognition and killing of virus infected cells, tumor cells, and transplanted grafts.

Bone Marrow:

Major organ of the immune system.

What complicates healing?

Malnutrition Obesity ↓d blood supply—↓s tissue perfusion, resulting in tissue ischemia Tissue trauma Denervation—interruption of nerve connection to an organ or body part Infection Disease—diabetes delays wound healing

Excess granulation tissue:

May have to be cauterized or cut off so healing can occur

Good about Fever?

Mild to moderate fever may be beneficial- a protove response in a person with normal immunity. It creates a hostile environment for pathogens. * inc. killing of microorganisms. *inc. pagoctyosis by neutrophils. *inc. T-cell proliferation. * Enhances activity of interferon- the boys natural virus fighting substance.

If patient is receiving a drug that surpasses bone marrow

Monitor WBC periodically

Chain of infection includes:

Pathogenic Microorganism Host susceptibility Reservoir Means of entry Mode of reansmission Means of escape

Spleen

Peripheral Lymphoid Organ. Located in LUQ beneath the diaphragm. Gathers and isolates workout erythrocytes, stores blood (lymphocytes) and 20-30% of platelets. Filters and removes foreign materials, dead cells, worn out cells, and cellular debris.

Plasma Cells:

Produce antibodies aka immunoglobulins. =Primary Immune Response

The immune system preserves the internal environment by:

Scavenging dead or damaged cells and by performing surveillance.

Potential for microorganisms to cause disease depends upon:

Sufficient number of organisms *Virulence *Ability to enter and survive in host *Susceptibility of the host

Infection can be:

Symptomatic and Asymptomatic

T suppressor cells:

Tell the immune system when the battle with the infectious pathogen is over and to stop fighting.

Wound Healing

The final phase of the inflammatory response.

Chemotaxis:

The movement of WBCs to an area of inflammation.

Lymph travels:

They usually travel through more than one lymph node because numerous nodes line the lymphatic channels that drain a particular region.

Where do T cells achieve immunocompetence?

Thymus

Other Accessory Organs:

Tonsils Adenoids Appendix Peter's patch Remove foreign debris in much the same manner as lymph nodes.

ANC

WBCs x % of neutrophils (bands and segs) = ANC If WBC is 3,600 mm3 and differential shows 23% segs and 1% bands.....the ANC is 3,600 x 24% or 3,600 x 0.24 = 864 mm3 Neutropenic precautions if ANC below 1,000.

Stimulated B cells?

When attached to antigen they are stimulated to proliferate, differentiate, and mature into either Plasma cells or memory B cells. However to be fully activated the y need T helper cells.

Immune System is:

a complex defense system of the body designed to recognize, respond to, and eliminate antigens.

Antigenicity

ability of a pathogen to stimulate an immune response in the host

PAthogenicity

ability to induce disease depends on speed of reproduction in host, extent of tissue damage and strength of toxin released

Infectivity

ability to invade and multiply

Toxicity

amount of destructive potential

Maintain skin integrity

first line of defense against infection. Monitor for early signs of pressure ulcers.

Opportunistic organisms

are microorganisms that are not usually considered pathogens. However, they may cause infection if the resistance of the host is ↓d from events such as immunosuppression, trauma, illness.

IgE

attaches to mast cells and basophils; triggers the release of histamine at the site and causes symptoms of allergic reactions; provides defense against parasites; IgE levels will be ↑ in persons with allergies or parasites. ↓ levels indicate ↑d risk for respiratory infections.

Immunity

body's capacity to resist invading organisms and toxins, thus preventing tissue and organ damage. It is an inherited, acquired, or induced resistance to infection by a specific pathogen

Vectors:

can deliver infection externally (flies) or internally (mosquito or tick bites).

IgA

found in exocrine secretions (saliva, tears, breast milk, urogenital tract); protects mucosal surfaces from invasion by pathogenic bacteria and viruses.

IgD

found on the surface of B cells and helps regulate B cell function; important in antigen recognition.

Acute Illness

infective organism is growing and spreading rapidly. Toxins are produced that cause cell lysis and possibly cell death. The inflammatory response and immune reaction occur, as the body attempts to fight off the invading organism—this leads to more specific symptoms, such as the classic signs of inflammation, and signs specific to the site and pathogen.

IgG

most abundant in the blood (75% of all immunoglobulins in plasma); crosses placental barrier and protects newborns for several months; provides most natural and acquired immunity.

Incubation period

organism is establishing itself. It may be multiplying and spreading, but has not yet caused any symptoms. The person is contagious.

Direct Contact:

person to person or contact with a contaminated inanimate object

Carriers

persons or animals with no signs of disease but can transmit the pathogen to others.

Virulence

potency in producing severe disease

Tumor Necrosis Factor

produced by granulocytes, lymphocytes, and other cells. Stimulates the initial inflammatory response, specifically macrophages and granulocytes.

Rest and immobilization

promote healing by ↓ing inflammatory process, assisting in repair process, and ↓ing metabolic needs.

Oxygenation

promotes differentiation of fibroblasts and collagen synthesis; essential for cell growth and division.

Prodromal phase

symptoms begin to appear, but are generally nonspecific: Malaise Fatigue Anorexia ↑d pulse and RR Fever

Indirect contact:

transmission that requires a vehicle to transmit (vehicles include contaminated items, food improperly handled or prepared).

Reservoir:

where the pathogen can live but may or may not multiply.