Q4 Ch 17 Principles of Inflammation & Immunity

General Immunity (innate-native immunity or natural immunity)

*composed of inflammatory responses, skin, mucosa, antimicrobial chemicals on the skin, complement, and NK cells. *non-specific, cannot be transferred from one adult to another and is NOT an adaptive response *With inflammation, provides immediate protection against the effects of tissue injury and invading foreign proteins. *Barrier to prevent organisms from entering the body and can attack organisms that have already entered the body. *Inflammatory protection is immediate but ST, it does not provide true immunity on repeated exposure to the same organisms *Inflammation is a nonspecific body defense to invasion or injury and can be started quickly by almost any event, regardless of where it occurs or what causes it. So inflammation triggered by a splinter and that triggered by a burn to 50% of the body is the same, what differes is how widespread the symptoms of inflammation are. The splinter will be a local response in finger but the burn leads to system wide inflammatory response. * Infection is usually accompanied by inflammation; however inflammation can occur without infection (joint sprains, blisters, MI's)

antigens

A foreign protein or allergen that is capable of causing an immune response; protein on the surface of a cell.

proteins ons on human cell plasma membranes

Cells are surrounded by plasma membranes with diff proteins on or thru surface. In addition, each persons cells have unique surface proteins that are specific for that person called HLA's

Artificial passive immunity

May be used to prevent disease or death for patients exposed to rabies, tetanus, and poisonous snake bites.

Changes in Immune Function Related to Aging: Cell-mediated Immunity

Number of circulating T-lymphocytes decreases: skin tests for for TB may be falsely negative. Older patients are more at risk for bacterial and fungal infections, especially on skin and mucous membranes, in respiratory tract, and in GU tract.

Active immunity

Occurs when B cells encounter antigens and produce antibodies

Passive immunity

Occurs when antibodies against an antigen are transferred to a human after first being made in the body of another human or animal. Because these antibodies are foreign to the receiving human, they are recognized as non-self and eliminated quickly. For this reason passive immunity provides only immediate, short term protection against a specific antigen. It is used when an adult is exposed to a serious disease for which he or she has little or no actively acquired immunity.

Phagocytosis

The engulfing and destruction of invaders, which also rids the body of debris after tissue injury. Key process of inflammation ➔ Neutrophils and macrophages are most efficient

Cell mediated immunity regulates the immune system by providing ____________________.

cytokines

monokines

cytokines made by macrophages, neutrophils, eosinophils, and monocytes

lymphokines

cytokines produced by T-cells

monocyte

destruction of bacteria and cellular debris, matures into macrophage

RBCs

erythrocytes

Natural Active Immunity

immunity which results from the response of the body to the invasion of a pathogen. Occurs without human assistance and your body responds by actively making antibodies against that antigen. Natural active immunity is the most effective and the longest lasting.

stem cells

unspecialized cells that are able to renew themselves for long periods of time by cell division ➔ pluripotent (each cells has more than one potential outcome, it is undifferentiated when it's first generated in bone marrow, not yet committed to maturing into a specific blood cell type)

Natural Killer Cells (CD16+)

very impt for providing CMI. have direct cytotoxic effects on some non-self cells without first being sensitized conduct seek and destroy mission in the body to eliminate non-self cells. most effective in destroying unhealthy or abnormal self cells such as cancer cells and virally infected body cells

What are the five cardinal symptoms of inflammation?

warmth redness swelling pain decreased function *timing of stages may overlap

7 Steps of Phagocytosis

1. Exposure/invasion: leukocytes that engage in phagocytosis and stimulate inflammation are present in the blood and ECF. 2. Attraction: the WBC comes into direct contact with the target (antigen, invader, or foreign protein). Damaged tissues secrete chemotaxins that attract neutrophils and macrophages and release debris that binds to the surface of invading proteins 3. Adherence: binds the phagocytic cell to the surface of the target. Oponins are substances that increase contact of the cell with its target by coating the target cell. During inflammation coating the target makes it easier for phagocytic cells to stick to it. Substances that are opsonins are dead neutrophils, antibodies, and activated (fixated) complement proteins. 4. Recognition: occurs when the phagocytic cell sticks to the target cell and recognizes it as non-self. The phagocytic cells examine the universal product codes (HLA's) of whatever they encounter. Opsonins on cell surface make it even easier. 5. Cellular ingestion: target cell brought nside the phagocytic cell by phagocytosis (engulfment) 6. Phagosome formation: occurs when the phagocytes granules break and release enzymes that attack the ingested target. 7. Degradation: final step in which enzymes in phagosome digest the engulfed target.

Three processes needed for human protection through immunity are ____________________. Therefore, full immunity and immunocompetence requires the function and interaction of all three processes

1. immunity 2. antibody-mediated immunity (AMI) 3. cell-mediated immunity (CMI)

What leukocytes are involved in inflammation? What other cell type in impt in inflammation?

1. neutrophils, macrophages, eosinophils, basophils 2. tissue mast cells Neutrophils and macrophages destroy and eliminate foreign invaders. Basophils, eosinophils, and mast cells release chemicals that act on blood vessels to cause tissue-level responses that help neutrophil and macrophage actions

Immunity is most efficient in adults in their _____________ and declines with increasing age

20's and 30's

Cytokines

A small protein released by cells that has a specific effect on the interactions between cells, on communications between cells or on the behavior of cells. The cytokines includes the interleukins, lymphokines and cell signal molecules, such as tumor necrosis factor and the interferons, which trigger inflammation and respond to infections. **work like hormones, one cells produces a cytokine, which in turn exerts effects on other cells of immune system and on other body cells. The cells responding to the cytokine may be located close to or remote. Act like messengers.

immunocompetent

Having proper functioning of the body's ability to maintain itself and defend against disease • ability to develop an immune response, or the • ability to recognize antigens and respond to them

HLAs

Human leukocyte antigens; responsible for recognizing the body's own cells (match requires most HLAs to be the same) • serve as a universal product code for that person and only identical to the HLAs of an identical sibling. • one adults HLAs are recognized as foreign or "non-self" by the immune system of another adult, meaning they are antigens to another adult • HLAs on are the surfaces of most most body cells, not just leukocytes. They are a normal part of the person and determine the tissue type of a person, which is coded for the specific genes he/she inherits from both parents.

Natural Passive Immunity

Occurs when antibodies are passed from the mother to the fetus via the placenta or to the infant through colostrum and breast milk.

What are the risk factors for hyperacute rejection? What is treatment?

Occurs when the recipient has preexisting antibodies to antigens in the donated organ. Patients at greatest risk for hyper acute rejection are those who have HLA mismatching, have received donated organs of an ABO blood type different than their own, or have received a previous transplant. Patients who have received multiple blood transitions at any time in life before transplantation are at higher risk for hyper acute rejection.

Drugs to Prevent Transplant Rejection: Calcineurin Inhibitors

The inhibition of calcineurin stops the production and secretion of IL-2, which then prevents the activation of lymphocytes involved in transplant rejection Cyclosporine - Side effects include nephrotoxic, hen, tremor, CAD, hirsutism, gingival hyperplasia, opportunistic infections, malignancies, hyperuricemia, hepatotocivity Tacrolimus - side effects include nephrotoxic, hen, hyperkalemia, hypomagnesemia, hyperglycemia, opportunistic infections, malignancies

Cell-mediated immunity (CMI)

involves many WBC actions and interactions. it is adaptive or acquired immunity that is provided by lymphocyte stem cells that mature in the secondary lymphoid tissues of the thumbs and percortoical area of lymph nodes.

Agglutination

is a clumping action occurring when the antibodies link antigens together, forming large and small immune complexes. The irregular shape of the antigen-antibody complex increases the actions of macrophages and neutrophils.

Lysis

is cell membrane destruction, and it occurs when antibodies bind to membrane-bound antigens of some invaders. Antibody binding makes holes in the invader's membrane, weakening the invader, especially bacteria and viruses. This response usually requires that complement be activated and "fixed" to the immune complex.

Artificial active immunity nal nation are required asa booster to retain the protection

is protection developed by a vaccination or immunization. This type of immunity is used to prevent serious and potentially deadly illnesses. Small amounts of specific antigens are placed as a vaccination into your body. Your immune system then responds by actively making antibodies against the antigen. Because antigens used for this procedure have been specially processed to make them less likely to grow in the body (attenuated), this exposure usually does not cause the disease. Lasts many years, although repeated but smaller doses of the origi

Precipitation

is similar to agglutination but has a larger response. With precipitation, antibody molecules bind so much antigen that large antigen-antibody complexes are formed. These complexes cannot stay in suspension in the blood. Instead they form a large precipitate, which then can be acted on and removed by neutrophils and macrophages.

WBCs

leukocytes; white blood cells; protect the body from infection. ➔ recognition of self vs non-self ➔ destruction of foreign invaders, cellular debris, and unhealthy or abnormal self cells ➔ production of antibodies directed against invaders ➔ complement activation ➔ production of cytokines that stimulate increased formation of leukocytes in bone marrow and increase specific leukocyte activity

Inactivation (neutralization)

makes an antigen harmless without destroying it. Usually only a small area of the antigen, the active site, causes the harmful effects. When an antibody binds to an antigen's active site, covering it, the antigen is made harmless without destroying it.

To protect without causing harm, immune system cells exert actions only against ___________ proteins and cells. Immune system cells can distinguish between the body's own health cells and _________proteins and cells

non-self

What are the physiologic roles of natural killer cells?

nonselectively attack non-self cells, mutated cells, malignant cells, grafts and transplanted organs

Neutrophils

nonspecific ingestion and phagocytosis of microorganisms and foreign protein. Provides protection after invaders, especially bacteria, enter the body. ➔. mature neutrophils make up between 55-70% of the normal total WBC count. ➔ come from the stem cells and complete the maturation process in bone marrow. Usually growth from stem cell to mature neutrophil requires 12-14 days. Can be sped up by presence of specific growth factors (cytokines). Short life span of 12-18 hrs. ➔ also called granulocytes because of the large number of granules present inside each cell. Because this type of cell causes continuous, instant, nonspecific protection against organisms, the percentage and actual number of mature circulating neutrophils are used to measure a patients risk for infection: the higher the numbers, the greatest resistance to infection. (ANC count)

IgD

present in low blood concentrations in conjunction with IgM

immunity

protection from illness or disease that is maintained by the body's physiologic defense mechanisms. ➔ requires the interaction of immunity and inflammation working together ➔ Components of immunity include intact skin and mucous membranes and many different white blood cells (WBCs) and their products. ➔ immunity plays a role in repair of damaged tissues

HLA's are key for ____________ & ____________________. The immune systems cells constantly come into contact with other body cells and with any invader that enters the body. At each encounter the immune systems cells compare the surface protein HLAs to determine whether the encountered cell belongs to the body. If the encountered cells HLAs match the HLAs of the immune system cell, the encountered cell is ________ and not attacked. If they do not perfectly match the immune system cell, the encountered cell is ___________ or foreign. The immune system cells then takes action to neutralize, destroy, or eliminate this foreign invader.

recognition and self tolerance self non-self

Eosinophils

releases vasoactive amines during allergic reactions to limit these reactions ➔ come from the myeloid line and contain many vasoactive chemicals. Only 1-2% of the total WBC count normally. ➔ most active against infectiestations of parasitic larvae and also limits inflammatory reactions. ➔ Some eosinophils granules contain enzymes that degrade the vasoactive chemicals released by other leukocytes. This is why the number of circulating eosinophils increases during an allergic response

Recognizing self versus non-self is called __________________.

self-tolerance - the ability to recognize self cells versus non-self cells, which is necessary to prevent healthy body cells from being destroyed along with invading cells.

Maturational pathway of any stem cell depends on

the boyd's needs and the presence of specific growth factors that direct the cell to a pathway. For ex, erythropoietin is a growth factor for RBCs. When immature stem cells are exposed to erythropoietin, they commit to the erythrocyte pathway and eventually become mature erythrocytes (RBCs)

IgE

variable concentration in blood Assocaited with antibody mediated hypersensitivity reactions Binds to mast cells and causes their degranulation when an allergen binds to IgE antigen recognition sites

Specific Immunity

an adaptive protection that results in long term resistance to the effects of invading microorganisms. Responses are not automatic, which is why specific immunity is also known as acquired immunity. Body has to learn to generate specific immune responses when it is infected by or exposed to specific organisms. Lymphocytes develop actions and products that provide true immunity. These cells develop specific actions in response to specific invasion. The two divisions of specific immunity are AMI and CMI. Activation of both types require interactions with actions and cells of innate immunity.

Complement activation and fixation

are actions triggered by the IgG and IgM classes of antibodies that can remove or destroy antigen. (See discussion of complement in the General Immunity and Inflammation section for an explanation of how complement assists in immunity.) Binding of either IgG or IgM to an antigen provides a binding site for the first component of complement. Once the first complement molecule is activated, other proteins of the complement system are activated in a cascade.

Most immune cells come from the __________________ which is the source of all _________cells. Some mature here, and others leave and mature in different body cells. When mature, many immune system cells are released into the ____________ where they circulate to most body areas and have specific effects

bone marrow blood, blood

Left shift

common term for an alteration in the distribution of leukocytes in which there are increases in banded neutrophils (less mature form) usually in response to severe bacterial infection. A left shift indicates that the patients bone marrow cannot produce enough mature neutrophils to keep pace with the continuing infection and is releasing immature neutrophils into the blood. These immature neutrophils are of minimum benefit because they are not capale of phagocytosis.

IgG

composes at least 75% of circulating antibody population. Heavily expressed on second and sbsequent exposures to antigens to provide sustained LT immunity against invading microorganisms Activates classic component pathway and enhances neutrophil and macrophage actions

non-self proteins & cells include...

infected body cells, cancer cells, cells from other people, and invading organisms

Helper/Inducer T-Cells (CD4)

- easily recognize self cells vs non-self cells. - secrete cytokines that enhance activity of other WBCs and increase overall immune function when they recognize non-self (antigens) cells - increase bone marrow production of stem cells and speed up maturation - "calling to arms" various squads of WBCs involved in inflammatory, antibody , and cellular protective actions

Suppressor T-cells

- have the T8 lymphocyte antigen on membrane surfaces. - commonly called T8+ cells, CD8+ cells, or Ts cells. - help regulate CMI - prevent hypersensitivity on espouse to non-self cells or proteins. This action prevents the formation of antibodies directed against normal healthy cells, which is the basis for many autoimmune diseases. - secrete cytokines that have an overall inhibitory effect on most cells in the immune system

Antibodies

All antibodies are immunoglobulins, also called gamma globulins. A globulin is a protein that is globular rather than straight. Because antibodies are globular proteins, they are "globulins." The term immunoglobulin is used because they are globular proteins that provide IMMUNITY. Antibodies also are called gamma globulins because all free antibodies in the plasma separate out in the gamma fraction of plasma proteins during electrophoresis. The five antibody types are classified by differences in size, location, amount, and function

ANC

absolute neutrophil count -- this is the total WBC times a measure of the number of neutrophils present in the blood; a normal ANC is about 1500 cells (ANC of less than 500 cells is neutropenia).

Cytotoxic/Cytolytic T cells (Tc Cells)

Because they have the T8 protein present on their surfaces, they are a subset of suppressor cells. They destroy cells hat contain a processed antigens human leukocyte antigens (HLAs). This activity is most effective against self cells infected by parasites such as viruses or Protozoa. Parasite infected self cells have both self HLA proteins and the parasites antigens on the cell surface. This allows immune system cells to recognize the infected cell as abnormal, and the cytotoxic/cytolytic T-cell can bind to it, punch a hole, and deliver a lethal hit of enzymes to the infected cell, causing it to lyse and die

IgM

First antibody formed by newly sensitized B-Lymphocyte plasma cell 10-15% of circulating antibody population Especially effective at the antibody actions of agglutination and precipitation because of having 10 potential binding sites per molecule Activates complement pathway

What WBC's have the most important role in CMI?

T-lymphocytes - helper/inducer T-cells - suppressor T-cells - cytotoxic T-cells Natural Killer cells

Stage 3 of Inflammation

Key features are tissue repair and replacement. It is completed last, but begins at time of injury and is critical to final function of inflamed area. ➔ WBCs involved in inflammation start the replacement of lost tissues or repair of damaged tissues by inducing the remaining healthy cells to divide. ➔ In tissues that cannot divide, WBCs trigger new blood vessel growth and scar tissue formation. Because scar tissue does not act like the tissue it replaces, function is lost wherever scar tissue forms. For example, when heart muscles are destroyed by a myocardial infarction (heart attack), scar tissue forms in the area to prevent a hole from forming in the heart wall as the ischemic cells die. The scar tissue serves only as a patch; it does not contract or act in any way like heart muscle. So if 20% of the left ventricle is replaced with scar tissue, the effectiveness of left ventricular contraction is reduced by 20%.

Macrophages

Non specific recognition of foreign proteins and microorganisms; ingestion and phagocytosis. Assists with AMI and CMI Macrophage functions include phagocytosis, repair, antigen presenting/processing, and secretion of cytokines for immune system control. Inflammatory function is phagocytosis, they can easily distinguish between self and non self and their large size makes them very effective at trapping invading cells ➔ come from committed myeloid stem cells in bone marrow and form the mononuclear-phagocyte system. The stem cells first form monocytes, which are released into the blood at this stage. Limited activity until they mature. Most monocytes move from the blood into body tissues where they mature into macrophages. ➔ some are fixed in position within tissues and others can move within and between tissues. ➔ liver, spleen, and intestinal tract have large numbers of these cells

Complement

Part of innate immunity. Composed of a system of 20 different types of inactive plasma proteins that, when activated, act as enzymes and attract agents to enhance (or complement) cell actions of innate immunity. When stimulated, each type of complement protein i activated, joins other activated complement proteins, surrounds and antigen, and fixes or sticks to the antigen. This action makes immune cell attachment to antigens more efficient. Occurs quickly as a "cascade"

Drugs to Prevent Transplant Rejection: Corticosteriods

Prednisone (Deltasone) Prednisolone (Millipred, Orapred, Veripred) Broadly inhibit cytokine production in most leukocytes, resulting in generalized immunosuppression Side effects: hypertension, hyperlipidemia, osteoporosis, weight gain, cushinggoid appearance, opportunistic infection, glaucoma, GI ulcer formation, hyperglycemia

Toll-like receptors (TLRs)

Receptors on immune system cells of humans and other animals that interact with the surface of any invading organism and allow recognition of non-self so actions are taken to rid the body of this invader. •. key element for recognition for non-self cells involved in general and specific immunity

Changes in Immune Function Related to Aging: Inflammation

Reduced neutrophil function: counts may be normal but activity is reduced increasing risk for infection Leukocytosis does not occur during acute infection: patients have infection but not show expected changes in WBC counts Older adults may not have fever during inflammatory or infectious episodes: minor infections may be overlooked until the patient becomes severely infected or septic

Basophils

Releases histamine and heparin in areas of tissue damage, causing the s/sx of inflammation. Acts on blood vessels with basophil chemicals (vasoactive amines), which include heparin, histamine, serotonin, kinins, and leukotrienes. Basophils have sites that bind the stem part of IgE molecules which binds to and is activated by allergens. When allergens bind to the IgE on the basophil, the basophil membranes opens and releases the vasoactive amines into the blood, where most of them act on smooth muscle and blood vessel walls. Basophils stimulate both general inflammation and inflammation of allergic reactions. ➔ come from myeloid stem cells and make up only about 1% of the total circulating WBC count. ➔ heparin inhibits blood and protein clotting ➔ histamine dilates arterioles and constricts small veins, slowing blood flow and decreasing venous return. This effect causes blood to collect in capillaries and arterioles. ➔ kinins dilate arterioles and increase capillary permeability, causing blood plasma to leak into the interstitial space (vascular leak syndrome)

IgA

Secretory antibody present in high concentrations in secretions of mucous membranes and intestinal mucosa. - low circulating levels - most responsible for preventing infection in upper and lower respiratory tracts, GI tract, and GU tract

Values of WBC Differential for Peripheral Blood Representing a normal count

Shows the number and percent of the different types of circulating leukocytes. Most circulating neutrophils are segmented neutrophils, only a small percentage are band neutrophils or less mature forms. Problems such as sepsis cause the cirulating neutrophils to change from being mostly segmented to less mature forms. This is a LEFT shift or bandemia.

Stage 2 of Infllammation

The cellular exudate part of the response. ➔ Neutrophilia (increased # of circulating neutrophils) occurs. Exudate in form of pus occurs, containing dead WBCs, necrotic tissue, and fluids that escape from damaged cells. ➔ Neutrophils, basophils, and tissue mast cells are active in this stage. Under influence of cytokines, the neutrophil count can increase hugely within 12 hr after inflammation starts. Neutrophils attack and destroy organisms and remove dead tissue thru phagocytosis. Basophils and tissue mast cells continue or sustain the initial responses. ➔ In acute inflammation, the healthy adult produces enough mature neutrophils to keep pace with invasion and prevent the organisms from growing. At the same time the WBCs and inflamed tissues secrete cytokines, which allow tissue macrophages to increase and trigger bone marrow production of monocytes. ➔ the arachidonic acid (AA) cascade starts to increase inflammation in this phase, beginning by the conversion of fatty acids in plasma membranes into arachidonic acid (AA). The enzyme cyclooxygenase (COX) converts AA into chemicals that are further processed into the substances (mediators) that promote continued inflammation. Mediators include histamine, leukotrienes, prostaglandins, serotonin, and kinins. Anti-inflammatory drugs stop this cascade by preventing cyclooxygenase from converting AA into inflammatory mediators. ➔ When an infection stimulating inflammation lasts longer than just a few days, the bone marrow begins to release immature neutrophils, reducing the number of circulating mature neutrophils. This problem limits helpful effects of inflammation and increases the risk for sepsis.

Tissue Mast cells

These cells look like and have functions very similar to basophils and eosinophils. They maintain and prolong inflammation and allergic reactions rather than the bone marrow, they come from a different parent cells than leukocytes and do not circulate as mature cells. Instead, they differentiate and mature in tissues, especially those near blood vessels, lung tissue, skin, and mucous membranes. Mast cells have binding sites for the stems of IgE molecules and are involved in allergic reactions. They also response to the inflammatory products released by T-lymphocytes.

Changes in Immune Function Related to Aging: Antibody-Mediated Immunity

Total # of colony forming B-lymphocytes and the ability of these cells to mature into antibody secreting cells are diminished: older adults less able to make new antibodies in response to presence of new antigens. Thus, they should receive immunizations like flu shots, pneumococcal vaccination, and shingles. There is a decline in natural antibodies, decreased response to antigens, and reduction in amt of time the antibody response is maintained: Older adults may not have sufficient antibodies present to provide protection when they are re-exposed to microorganisms against which they have already generated antibodies. The older patients need to avoid people with viral infections and receive booster shots for old vaccinations and immunizations, especially tetanus and pertussis (whooping cough)

Antibody-mediated immunity aka AMI, humoral immunity

Uses antigen-antibody interactions to neutralize, eliminate, or destroy foriegn proteins. Antibodies are produced by sensitized B-lymphocytes (B-cells). Becomes sensitized to foreign cells and proteins with the assistance of macrophages and helper/inducer T-cells. ➔ B-cells become sensitized to a specific foreign protein (antigen) and produce antibodies directed specifically against that protein. The antibody, rather than the B-cell, then causes actions to neutralize, eliminate, or destroy that antigen. B-cells have the most direct role in AMI. ➔ B cells start as stem cells in the bone marrow, the primary lymphoid tissue, that commit to the lymphocyte pathway and tare then restrictedi n development. The lymphocyte stem cells released into the blood then migrate to many secondary lymphoid tissues to mature. The secondary lymphoid tissues for B-cells are the spleen, parts of lymph nodes, tonsils, and the mucosa of the intestinal tract. ➔ Macrophages and T-lymphocytes work with B-cells to generate antigen-antibody reactions. For optimal AMI, the entire immune system must function adequately.

Stages 1 of Inflammation

Vascular response that starts changes in blood vessels. ➔ Injured tissues and the leukocytes and tissue mast cells in this area secrete histamine, serotonin, and kinins that constrict the small veins and dilate the arterioles. This causes redness and warmth of tissues, increased blood flow increases delivery of nutrients to injured tissues. ➔ Hyperemia (increased blood flow) and edema forms at site of injury or invasion. Capillary leak also occurs, allowing blood plasma to leak into tissues. Edema protects the area from further injury by creating a cushion of fluid. The duration of these responses depends on the severity of the initiating event, but they usually subside within 24-72 hrs. ➔ Macrophage is major cell involved in this stage. The action is rapid b/c macrophages are already in place at injury site or invasion. Action is limited because number of macrophages is so small. To enhance response, tissue macrophages secrete several cytokines. One is colony-stimulating factor (CSF) which triggers the bone marrow to shorten the time needed to produce WBCs from 14 days to a matter of hours. Some cytokines cause neutrophils from bone marrow to move to site of injury of invasion which leads to next stage of inflammation.

antibody-mediated immunity

adaptive immunity in which a person's body learns to make as an adaptive response to invasion by organisms or foreign proteins. Thus it is an acquired immunity. adaptive immunity occurs either naturally or artificially through lymphocyte response and can be either active or passive.

Other names for HLA's include

human histocompatibility antigens class I antigens

7 Steps for Specific Antibody Production Against a Specific Antigen

➔ Exposure or Invasion ➔ Antigen Recognition: recognition of the antigen by unsensitized B-cells. This action requires the help of macrophages and helper/inducer T-cells ➔ Sensitization: occurs when the B-cell recognizes the antigen as non-self and is now sensitized to this antigen. A single unsensitized B-cell can become sensitized only once, for one type of antigen. ➔ Immediately following sensitization, the B-cell divides and forms two types of B-lymphocytes, each one remaining sensitized to that specific antigen. One new cell becomes a plasma cell, which starts immediately to produce antibodies against the sensitizing antigen. The other new cell becomes a memory cell which is a sensitized B-cell that does not produce antibodies until the next exposure to the same antigen. ➔ Antibody production and release allow the antibodies to search out specific antigens. Antibodies are produced by plasma cells; each plasma cell can make as many as 300 molecules of antibody per second. Antibody molecules from plasma cells are released into the body. fluids and blood. They can be transferred from one adult to another and provide the receiving adult with immediate short-term immunity ➔ antibody-antigen binding is needed for anti-antigen actions. Antibodies are Y shaped molecules. The tups of the short arms of the Y recognize the specific antigen and bind to it. Because each antibody molecule has two tips (Fab fragments or arms), each antibody can bind either to two separate antigens or on two areas of the same antigen. The stem of the Y is the Fc fragment. This area can bind to Fc receptor sites on WBCs. The WBC then not only has its own means of attacking antigens but also has the added power of having surface antibodies that can stick to antigens. The binding may not be lethal to antigen, instead other actions that neutralize, eliminate, or destroy action are triggered (agglutination, lysis, complement activation and fixation, precipitation, inactivation/neutralization ➔ Sustained immunity (memory) provides us with long lasting true immunity to a specific antigen. This immunity results from memory B-cells made during lymphocyte sensitization. On re-exposure to same antigen, the memory cells rapidly respond by dividing and forming new sensitized blast cells and plasma cells. The blast cells continue to divide producing many more sensitized plasma cells.