Immunology Exam 1 (Ch. 1 Innate Immunity)

Disease

Communicable

Condition

Something you or someone else has

Immunology

The study of reaction when host encounters a foreign substance

Is anything wrong with the definition of immunology?

Yes, the definition does not encompass autoimmune response

Antigen

Foreign substance causing a response, IT IS DIFFERENT FROM YOURSELF!

“Infectious agent”
Can be environmental substances or synthetic structures

Immunity

Discrimination between self and nonself and the subsequent protection from nonself

Immune system

System in an individual that is related to the immune response

How do bacteria protect from bacteriophages?

They methylate their own DNA.
Bacteriophages have no methylation pattern so they will degrade their DNA.

How was recognition of self proved?

Sponges were blended and put into water. They then segregated themselves back.

Innate immunity

Available quickly and nonspecific. Depleted quickly

Fluids

Acquired immunity

Specific, large, ability to discriminate, memory

Solid w/ cells

How does innate immunity prevent pathogen entry?

Structural barriers: skin, cough, sneeze, mucus, ear wax

Acidic secretions: sweat, sebaceous glands, vagina, stomach lysozyme present in skin, stomach tears

Normal flora: prevent other bacteria from growing, affected by antibiotics

Components of blood

Plasma

Buffy coat

Erythrocytes

What is in the buffy coat?

Leukocytes and platelets

Formed elements of blood

Buffy coat and erythrocytes

Plasma

Anticoagulant

Serum

No anticoagulant

What are the only true complete cells?

White blood cells

Where do platelets come from?

Megakaryocytes

Terminal

Most differentiated they can be

Where do blood cells go to be renewed?

The bone marrow

Diapedesis

The way that leukocytes leave the capillaries to move through tissue spaces

Leukocytosis

Increase in WBC count over 11

What is a critical value for leukocytosis?

>30

Leukemia

WBC count over 50-100

Leukopenia

Decrease in WBC count

CD markers

Surface markers that differentiates WBCs from each other

CD marker for all WBCs

CD 45+

CD4

T helper cell

CD8

Cytotoxic T cell

Granulocytes

Neutrophils (50%)

Eosinophils (2-4%)

Basophils (0.5-1%)

What system do granulocytes play a part in?

Innate system

Agranulocytes

Lymphocytes (25-45%)

Monocytes (3-8%)

What system do agranulocytes play a part in?

Innate and acquired system

What cells are found in blood?

Granulocytes

Monocytes

Lymphocytes

What categories can lymphocytes be separated into?

NK cells

LAK cells

NK cells

Natural killer cells

Not antigen specific

Kill tumor cells and virally infected cells

Can respond to bacterial and protozoal infections

LAK cells

Lymphokine-activated killer cells

More efficient at killing target

Used in cancer therapy

What cells are in tissues?

Macrophages

Mast cells

Dendritic cells

Macrophages

Terminal monocytes

Mast cells

Produce histamine, allergy symptoms

Dendritic cells

Branches

Dendritic cells and macrophages

Activate lymphocytes

Characteristics of granulocytes

Larger, shorter-lived than RBCs

Lobed nuclei

Phagocytic

Neutrophils

Attracted to site of inflammation, first responders

Judge maturity based on multi-lobulated nucleus

Function of neutrophils

Non-specifically destroy bacteria and some parasites

They just kinda eat stuff

What dyes do neutrophils take up?

They take up blue and red

The cytoplasm will have a lilac color

Neutral staining

CD markers of granulocytes

CD45+ and CD15+

What do eosinophils stain as?

Red
Basic components

What do basophils stain as?

Blue

Acidic components

How long do neutrophils live for?

12 hours in blood

1-2 days in tissue

Neutrophil antigen presentation

Eat and digest bad things and presents the antigen back out to other cells

Downsides of neutrophils

Cells can attack your own cells

Chemotaxins

Attract neutrophils to site of infection

Eosinophils

Lead body’s counterattack against parasitic worms by getting together and stabbing proteins into cell membranes

Lessen severity of allergies by phagocytizing immune complexes

Shape of eosinophils

Bilobed nucleus

Like a bent barbell

Basophils

Function is not completely defined

Granules contain histamine which acts as a vasodilator and attracts other WBCs to the area

Shape of basophils

U or S shaped nuclei with 2 or 3 conspicuous constrictions

Mast cells

Surface receptor for IgE
Contain histamine and heparin

What reactions do mast cells take place in?

Allergic reactions and antiparasitic reactions

Where are mast cells found?

Tissues, CT, and near mucosal surfaces

Macrophages

In the tissue

Second responders that clean up

Phagocytizes pathogens and is important in antigen presentation

Several month life span

CD marker for macrophages

CD14+

When are dendritic cells immature

When they are in the blood stream

When are dendritic cells mature

When they are in tissues

CD marker for dendritic cells

CD11c+

CD marker for NK cells

CD3- CD56+ and CD16+

How do NK cells kill their targets directly?

Secrete perforins and granzymes into target

First is perforation, then the granzymes go in

Antibody Directed Cellular Cytotoxicity (ADCC)

A method in which NK cells kill targets

Surface CD16 binds antibody coated target cells

Ig binds to target cell → CD16 binds to Ig

How are LAK cells formed

NK cells have surface receptors for the cytokine IL-2

Pattern Recognition Receptors (PRRs)

Recognize surface molecules expressed in groups of microorganisms

Found on our cells

Toll-like receptors

After binding, phagocytosis

What do PRRs bind to?

PAMPs

Pathogen-associated molecular patterns (PAMPs)

Common ones are: unmethylated DNA, DNA with increased amounts of CpG, ds and ss RNA, terminal mannose, LPS, flagellin, and peptidoglycan

Function of PAMPs

Open up the cell membrane for phagocytosis

Acute phase reactants (APRs)

Bind to cell wall of microbe which weakens its membrane and increased permeability to kill pathogen

Increase during inflammation

What are the 2 major families of antimicrobial peptides

Defensins and cathelicidins

C-reactive protein

Measures the risk of cardiovascular disease

Sensitive indicator of inflammation

Activates complement

Opsonin

Alpha-1 acid glycoprotein

Produced by the liver

Primary function may be the inhibition of progesterone and other drugs

Haptoglobulin

Binds to free hemoglobin released by intravascular hemolysis

Complexes are cleared in the liver

Goes up as RBCs are lysing, mop up hemoglobin

Serum Amyloid A

Apolipoprotein (transports lipids)

Associated with HDL in the blood

Involved in cholesterol transport to the liver

Repair of infection-caused tissue damage

Bringing cells to the site of infection

Complement system

Lyse cells that aren’t supposed to be there

Involved in inflammation, opsonization, chemotaxis, and lysis of cells

What are the three pathways of activation for the complement system?

Classical

Alternative

Lectin

Classical pathway

Only functions with antibody bound to antigen so it’s linked to the acquired immune system

Alternative pathway

Begins with spontaneous hydrolysis of some of the C3 that is in the serum

Lectin pathway

Binds mannose on the surface of pathogens

Mannose binding lectin

A PRR that is associated with enzymes that bind and cleave the complement component C4

Cleaved C4 binds to C3 and thus complement is activated

Inflammation

Overall reaction of the body to injury/invasion that brings the response to the infection

Helps eliminate, repair, and remove debris

Major events of inflammation

Increase in blood supply and capillary permeability

Migration of neutrophils and then macrophages to the site

Chemotactic factors

Include complement pathway products, cytokines, and other cellular components

Phagocytosis

Leukocytes engulf, digest, and kill microbes

How do phagocytes attach to cells

PRRs bind to PAMPs

Opsonins tag cells

Cellular part of the innate immune system

Phagocytosis

Humoral part of the innate immune system

Acute phase reactants