Inflammation, Immunity, and Neoplasia Flashcards

Flashcards about Inflammation, Immunity, and Neoplasia

Inflammation

Response at the level of tissues, organs, or systemically to destroy, dilute, or sequester injurious agents and incite healing.

Healing

Repair of damaged tissue by hyperplasia (regeneration) or fibrosis.

Allergy

An immune response to otherwise harmless environmental substances.

Autoimmunity

An immune response to self antigens.

Adjuvants

Pro-inflammatory compounds added to killed vaccines and toxoids to nonspecifically increase the body’s immune response.

Selectins and sialylated Lewis X receptors

Adhesion molecules that bind complementary receptor proteins on leukocytes that contain a complex sugar called “Lewis X” and a sialic acid moiety.

P-selectin

temporary binding of neutrophils to platelets, which permits transcellular metabolism to form lipoxins.

Lipoxins

Molecules that cause effects that tend to oppose the inflammatory leukotrienes and inhibit leukocyte recruitment

Cell Adhesion Molecules (CAMs)

Proteins which bind complementary receptors on leukocytes that are integrins.

Leukocyte adhesion deficiencies

Deficiencies that result in fewer leukocytes exiting blood vessels during an inflammatory response, and a corresponding increase in the frequency and severity of bacterial infections.

Acute

Indicates a process that began recently.

Chronic

Indicates a process with an extended time course and any inflammatory process with fibrosis (collagen deposition).

Focal

Means in a single spot or region.

Multifocal

Means similar lesions are scattered in many spots.

Diffuse

Indicates that the lesion is distributed evenly throughout most or all of the examined tissue.

Suppurative

Indicates a prominent component of neutrophils.

Granulomatous inflammation

Is always chronic, and contains large reactive macrophages which are often called “epithelioid macrophages”.

Neutrophils

Cell type generally the first to respond in acute (non-viral) inflammation or to necrosis.

Lymphocytes

Cell type that is usually the first to respond to viral infections or autoimmune diseases.

Macrophages

Cell type that begin to appear a few days after the onset of inflammation from almost any cause, and increase in numbers over time.

eosinophilic inflammation

Inflammation that is highly suggestive of a response to helminths, arthropods, or allergens.

Chemotactic factors

Stimulate leukocytes to migrate towards an increasing chemotactic gradient and include foreign substances, chemical mediators, and chemokines.

Opsonization

Labelling an organism for removal.

Collectins

Are lectins that opsonise bacteria and link to receptors on leukocytes

Damaging effects of phagocytes

Migration, phagocytosis, and degranulation can kill micro-organisms

Nitric oxide (NO)

Can be produced by macrophages from the action of inducible nitric oxide synthase (iNOS).

haemostatic, kinin, fibrinolytic, and complement systems

Reactions are each stimulated under similar conditions and contributes to inflammation.

C3a and C5a

Causes vascular leakage and are called anaphylatoxins

C5a

Causes vascular leakage, is a chemotactic factor, and activates leukocytes

C3b (opsonin)

Opsonises bacteria to enable phagocytosis by neutrophils

C5-9 is the Membrane Attack Complex (MAC)

which punches holes in plasma membranes to cause bacterial or cell lysis

Cell membrane phospholipids

Metabolized to arachidonic acid by phospholipases

Corticosteroids

Potent anti-inflammatory drugs that block AA production

lipoxygenase enzyme pathways

AA is metabolized that produce leukotrienes (LTB4, LTC4, LTD4, LTE4).

LTB4

Has strong chemotactic properties

LTC4, LTD4, and LTE4

Induce the classical symptoms of asthma - vasoconstriction, increased vascular permeability, & bronchospasm

lipoxins

The actions of lipoxins appear to be opposite of those of the leukotrienes

prostacyclin (PGI2)

Inhibits platelet aggregation and causes vasodilation

thromboxane (TXA2)

Promotes platelet aggregation and causes vasoconstriction

Nonsteroidal Anti-inflammatory Drugs (NSAIDS)

Inhibit COX enzymes

Acute phase reaction

Systemic effects of infection that include a series of responses

IL-1, TNF, IL-6, and PGE2

mediate fever, together with inappetence and sleepiness

tissues of elderly animals

Have a decreased capacity to enter mitosis, and thus heal more slowly

fibroplasia

Growth of fibroblasts and the collagen they produce

granulation

Coordinated proliferation of fibroblasts with a rich bed of capillaries

growth factors that promote fibroplasia and angiogenesis

Includes: Fibroblast Growth Factors, Epidermal Growth Factor, Transforming Growth Factors, Platelet Derived Growth Factor, and Vascular Endothelial Growth Factors

Adult stem cells

Has the ability to regenerate cells of a restricted type or group (e.g. mesenchymal cells)

Embryonic stem cells

Are derived from embryos, and are pluripotent

the speed of healing and amount of cutaneous scarring

Influenced by the depth and width of the wound, the ability to approximate (bring together) the cutaneous edges, and the occurrence of infection

healing by first intention

Wound edges are held together, so the amount of granulation tissue needed to bridge the defect is reduced

healing by second intention

Occurs in larger defects in which the wound cannot be closed with sutures

Exuberant granulation tissue

Open skin wounds of the distal limbs on Horses where the exuberant healing response may create a raised protruding mass of red granulation tissue

Chronic inflammation

Failure to get rid of the cause of the inflammation

T Cell Receptors (TCR)

Subset of T cells with 60-70% circulating lymphocytes, where 95% have á/â TCR and 5% have ã/ä TCR

CD4+ and CD8+ T cells

Distinct subsets of T cells that co-express either CD4 or CD8 molecules

B lymphocytes

Cell that makes up 10% of circulating lymphocytes

Natural Killer (NK) cells

Also called Large Granular Lymphocytes (LGLs).

MHC = Major Histocompatibility Complex (HLA in humans)

All nucleated cells express this and is co-expressed with â2 microglobulin

Toll-like Receptors

TLRs, Complement, and other innate defense molecules have conserved receptors that are important for innate immune responses

Hypersensitivity reactions

All require prior sensitization of the individual, from past exposure to the offending antigen

Type I hypersensitivity

Reactions that can be localised or systemic

Anaphylaxis

Severe type I hypersensitivity reactions with systemic involvement, most often including laryngeal oedema, bronchospasm, and systemic hypotension

type I hypersensitivity

common cause of pruritic dermatitis, especially in dogs, which is often referred to as “atopy” or “atopic dermatitis”

Asthma

Targets airways and respiratory mucosa and is most common in people, but also occurs in cats

Heaves

An allergic bronchitis with bronchial constriction in horses known as

Type II hypersensitivity

Type of hypersensitivity that involves IgG or IgM attaches to antigens on cell surface and also may be lysed by NK cells

Type III hypersensitivity

Involves formation of insoluble antigen-antibody immune complexes

Arthus reaction

Local necrosis from type III vasculitis, usually in the skin

Type IV hypersensitivity

Cell mediated immune reaction, characterised by dense infiltrates of sensitized T- cells

Type IV hypersensitivity

Is called “Delayed Type Hypersensitivity” (DTH)

Organ transplant rejection usually involves type IV hypersensitivity

Refers to Autoimmunity

Breakdown of T-cell anergy, Molecular mimicry, Polyclonal lymphocyte activation, Exposure of sequestered antigens, Failure of suppressor T cells, Failure of apoptotic mechanisms to remove autoreactive T cells

Proposed mechanisms of the development of autoimmunity

Specific Autoimmunity

Specific autoimmunity vs. polyclonal, systemic autoimmunity

Systemic Lupus Erythematosus (SLE)

The classic example of polyclonal assaults

Multifactorial Pathogenesis

Limited vs Polyclonal Specificity of Autoimmunity

Multiple sclerosis

Autoimmune disease of humans characterized by repetitive, sporadic episodes of immune mediated destruction occur in white matter of the CNS

Primary (i.e. genetic) Immunodeficiencies

Are numerous, rare, and have provided important evidence about the function of the immune system, but most well-studied conditions are from human cases

CMI deficiency diseases

Manifests quickly

Leukocyte Adhesion Deficiencies

Occur if integrin or selectin adhesion molecules are altered

The Chédiak-Higashi syndrome

Has a problem with production and fusion of lysosomes prevents formation of phagolysosomes

Chronic Granulomatous Disease of children

Is a deficiency of enzymes in the NADPH oxidase, myeloperoxidase, halide complex, leading to poor microbial killing by neutrophils

Acquired Immunodeficiencies

Similar to Human Immunodeficiency Virus (HIV) which causes AIDS, Bovine (BIV), Feline (FIV), and Simian (SIV) Immunodeficiency viruses cause similar problems in animals

Failure of Passive Transfer (FPT)

The most common immunodeficiency in domestic animals

Amyloidosis

Extracellular accumulation of an amorphous, pale pink material

AL amyloid

Associated with tumours or dyscrasias of Ig producing cells and is composed of masses of Ig, Ig light chains, or portions of Ig light chains

AA amyloid

Composed of portions of Serum Amyloid A and is associated with chronic inflammation or tissue destruction that induces a sustained “acute phase reaction” response with prolonged secretion of SAA by hepatocytes

Systemic amyloidosis

Is generally associated with a poor prognosis, because it is both a result of a serious underlying condition, and a further cause of serious problems

Hamartoma

An abnormally organised, usually small mass of well-differentiated tissue, occurring in the normal location of that tissue

Choristoma

A small amount of normal tissue in an abnormal location

Hypoplasia

Underdevelopment of an organ with fewer than the normal number of cells

Hyperplasia

A Reversible disorder that may be physiological or pathological

Hypertrophy

May be physiological or pathological reversible disorder

Dysplasia

Has two connotations, depending upon the context and also may resolve or progress to an irreversible condition: neoplasia

Neoplasia

Not reversible even if the inciting stimuli are removed

Carcinogenesis

The development of cancer is a multi-step process involving mutation of DNA

Carcinogen

is a substance that induces the formation of cancer

Initiation

the first step to induce a cancer-susceptible state and is the result of DNA mutations

Promotion

Stimulation of initiated cells to undergo mitosis and this makes permanent the initial DNA error

Progression

Refers to serial mutational events that confer ever-increasing transformation of an altered cell line

Metastasis

Transplantation and growth of neoplastic cells in distant sites from the original mass