Immunology Lec1

Immunology

Immunology

study of a host’s reactions when foreign substances are introduced into the body.

antigens

A foreign substance that induces such an immune response is called _____________

immunity

the condition of being resistant to infection

1960s

It was not until the ______ that the cells responsible for the immune response were identified and characterized.

smallpox scab

The first written records of immunological experimentation date back to the 1500s, when the Chinese developed a practice of inhaling powder made from ________s in order to produce protection against this dreaded disease.

variolation

The prac tice of deliberately exposing an individual to material from smallpox lesions was known as ________

Edward Jenner

An English country doctor by the name of___________discovered a remarkable relationship between exposure to cowpox and immunity to smallpox.

vaccination

This procedure of injecting cellular material became known as ________

vacca

Vaccination came from the latin word _____ which means cow

cross-immunity.

The phenomenon in which exposure to one agent produces protection against another agent is known as ________.

Attenuation

may occur through heat, aging, or chemical means, and it remains the basis for many of the immunizations that are used today.

Louis Pasteur

In working with the bacteria that caused chicken cholera, _____________, a key figure in the development of both microbiology and immunology, accidentally found that old cultures would not cause disease in chickens

rabies

Pasteur applied the same principle of attenuation to the prevention of _________, a fatal disease at that time.

Elie Metchnikoff

a Russian scientist, observed that foreign objects introduced into transparent starfish larvae became surrounded by motile cells that attempted to destroy these invaders. He called this process phagocytosis.

Phagocytosis

Process by which cells eat cells.

Almoth Wright

In 1903, an English physician named ____________linked the two theories by showing that the immune response involved both cellular and humoral elements

opsonins

Wright observed that certain humoral, or circulating, factors called _____________acted to coat bacteria so that they became more susceptible to ingestion by phagocytic cells.

antibodies, acute-phase reactants

These serum factors include specific proteins known as and nonspecific factors called__________ that increase nonspecifically in any infection.

Natural, or innate immunity

is the ability of the individual to resist infection by means of normally present body functions.

No prior exposure is required, and the response does not change with subsequent exposures.

Acquired immunity

is a type of resistance that is characterized by specificity for each individual pathogen, or microbial agent, and the ability to remember a prior exposure, which results in an increased response upon repeated exposure.

External

_______defense system is designed to keep microorganisms from entering the body.

inflammation

The process of________ brings cells and humoral factors to the area in need of healing

external defense system

is composed of structural barriers that prevent most infectious agents from entering the body.

lactic acid in sweat and fatty acids from sebaceous glands

maintain the skin at a pH of approximately 5.6. This acid pH keeps most microorganisms from growing.

urine

he flushing action of ______, plus its slight acidity, helps to remove many potential pathogens from the genitourinary tract

Lysozyme

is an enzyme found in many secretions such as tears and saliva, and it attacks the cell walls of microorganisms, especially those that are gram-positive.

competitive exclusion

In many locations of the body, there is normal flora that often keeps pathogens from establishing themselves in these areas. This phenomenon is known as

Internal defense system

is designed to recognize molecules that are unique to infectious organ- isms.4 This typically involves recognizing a carbohydrate such as mannose that is found in microorganisms and is not evident on human cells.

Phagocytosis

This process destroys most of the foreign invaders that enter the body, and it is the most important function of the internal defense system.

acute-phase reactants

Phagocytosis is enhanced by soluble factors called __________________.

Acute-phase reactants

are normal serum constituents that increase rapidly by at least 25 percent due to infection, injury, or trauma to the tissues.5

hepatocytes

liver parenchymal cells

hepatocytes

Acute phase reactant are produced by _________.

12-24

Acute phase reactant are produced within _________.hours

cytokines

intercellular signaling polypeptides

IL-1β, IL-6, TNF-α

Most common cell messengers

monocytes and macrophages

IL-1β, IL-6, TNF-α are produced by ______at the sites of inflammation

C-reactive protein

is a trace constituent of serum originally thought to be an antibody to the c-polysaccharide of pneumococci. It increases rapidly within 4 to 6 hours following infection, surgery, or other trauma to the body.

19 hours

Plasma half-life of C-Reactive Protein

age

C-Reactive Protein is directly proportional to ___

118,000 daltons

C-reactive protein is a homogeneous molecule with a molecular weight of _____________ and a structure that consists of five identical subunits held together by noncovalent bonds.

C-Reactive proteins

acts somewhat like an antibody, as it is capable of opsonization (the coating of foreign particles), agglutination, precipitation, and activation of complement by the classical pathway.

phosphocholine

common constituent of microbial membranes.

phosphocholine

main substrate of CRP

CRP

an be thought of as a primitive, nonspecific form of antibody molecule that is able to act as a defense against microorganisms or foreign cells until specific antibodies can be produced.

CRP

The most widely used indicator of acute inflammation

1.5 mg/L for men to 2.5 mg/L for women

Normal levels CRP for men and women, respectively

Serum amyloid A

It is an apolipoprotein that is synthesized in the liver and has a molecular weight of 11,685 daltons

30ug/ml

Normal circulating levels are approximately of Serum Amyloid A is

serum amyloid A

By removing cholesterol from cholesterol-filled macrophages at the site of tissue injury, _________contributes to the cleaning up of the area.

Alpha1-Antitrypsin

general plasma inhibitor of proteases released from leukocytes, especially elastase.

Elastase

Is an endogenous enzyme that can degrade elastin and collagen.

alpha1-antitrypsin

acts to “mop up” or counteract the effects of neutrophil invasion during an inflammatory response. It also regulates expression of proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin-1�, and interleukin-6, mentioned previously.

premature emphysema

Alpha1-antitrypsin deficiency can result in ___________-

Homozygous inheritance of this most severe variant gene may lead to development of cirrhosis, hepatitis, or hepatoma in early childhood.6

Fibrinogen

is the most abundant of the coagulation factors in plasma, and it forms the fibrin clot.

100 to 400 mg/dL

Normal levels of fibrinogen

340,000

Fibrinogen, is a molecule , is a dimer with a molecular weight of _______ daltons

thrombin

A small portion of fibrinogen is cleaved by________ to form fibrils that make up a fibrin clot.

Haptoglobin

is an alpha2-globulin with a molecular weight of 100,000 daltons. Its primary function is to bind irreversibly to free hemoglobin released by intravascular hemolysis.

de novo synthesis

The rise in plasma haptoglobin is due to__________ by the liver and does not represent release of previously formed haptoglobin from other sites

40 to 290 mg/dL

Normal plasma concentrations range from ___________________

Haptoglobin

____________ plays an important role in protecting the kidney from damage and in preventing the loss of iron by urinary excretion

free hemoglobin

a powerful oxidizing agent that can generate peroxides and hydroxyl radicals

Ceruloplasmin

consists of a single polypeptide chain with a molecular weight of 132,000 daltons.6 It is the principal copper-transporting protein in human plasma, binding 90 to 95 percent of the copper found in plasma by attach- ing six cupric ions per molecule.

Wilson’s disease

A depletion of ceruloplasmin is found in _________, an autosomal recessive genetic disorder characterized by a massive increase of copper in the tissues.

Complement

refers to a series of serum proteins that are normally present and whose overall function is mediation

Mannose-Binding Protein

is a trimer that acts as an opsonin, which is calcium-dependent. It is able to recognize foreign carbohydrates such as mannose and several other sugars found primarily on bacteria, some yeasts, viruses, and several parasites.

granulocytes

Neutrophils, eosinophils, and basophils are considered _________.

Neutrophil

represents approximately 50 to 70 percent of the total peripheral white blood cells.

Neutrophils

These are around 10 to 15 µm in diameter, with a nucleus that has between two and five lobes They contain a large number of neutral staining granules, which are classified as primary, secondary, and tertiary granules.

azurophilic granules

Primary granules, also called _______________, contain enzymes such as myeloperoxidase; elastase; proteinase 3; lysozyme; cathepsin G; and defensins, small proteins that have antibacterial activity.2

Secondary granules

are characterized by the presence of collagenase, lactoferrin, lysozyme, reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and other membrane proteins normally associated with the plasma membrane.

lysosomes

Acid hydrolases are found in separate compartments called

diapedesis

Marginating occurs to allow neutrophils to move from the circulating blood to the tissues through a process known as ___________, or movement through blood vessel walls.

selectins

Receptors known as selectins help make neutrophils sticky and enhance adherence to______________ that make up the vessel wall.

Chemotaxins

are chemical messengers that cause cells to migrate in a particular direction.

5

Once in the tissues, neutrophils have a life span of about __days

Eosinophil

are approximately 12 to 15 µm in diameter, and they normally make up between 1 and 3 percent of the circulating white blood cells in a nonallergic person. Their number increases in an allergic reaction or in response to many parasitic infections.

Eosinophil

The nucleus is usually bilobed or ellipsoidal and is often eccentrically located

eosinophil

Their most important role is neutralizing basophil and mast cell products and killing certain parasites

Basophils

are found in very small numbers, representing less than 1 percent of all circulating white blood cells. The smallest of the granulocytes, they are between 10 to 15 µm in diameter and contain coarse, densely staining deep-bluish- purple granules that often obscure the nucleus

Basophils

Constituents of these granules are histamine, a small amount of heparin, and eosinophil chemotactic factor-A, all of which have an important function in inducing and maintaining immediate hypersensitivity reactions

Histamine

Is a vasoactive amine that contracts smooth muscle

Tissue mast cells

___________ resemble basophils, but they are connective tissue cells of mesenchymal origin. They are widely distributed throughout the body and are larger than basophils, with a small round nucleus and more granules

9 to 18 months

Lifespan of mast cells

enzyme content

How can you distinguish basophils from mast cells?

IgE

the immunoglobulin formed in allergic reactions

Monocyte

are the largest cells in the peripheral blood, with a diameter that can vary from 12 to 22 µm; they have an average size of 18 µm

horse-shoe shaped nucleus

What is the distinguishing feature of monocyte?

Monocyte

The abundant cytoplasm stains a dull grayish blue and has a ground-glass appearance due to the presence of fine dustlike granules.

70

Monocyte stays in peripheral blood for __ hours

macrophages

Monocyte stays in peripheral blood for hours and then migrate to the tissues and become knows as _________

monocyte

Macrophage precursor

alveolar macrophages

Macrophages in the lung are

Kupffer cells

Macrophages in the liver

microglial cells

Macrophages in the brain

histiocytes

Macrophages in the connective tissue

cytokines

Killing activity is enhanced when macrophages become “activated” by con- tact with microorganisms or with chemical messengers called ______, which are released by T lymphocytes during the immune response.

Dendritic

____________cells are so named because they are covered with long membranous extensions that make them resemble nerve cell dendrites.