bio2 exam 5

Interferons

released by viral infected cells so nearby cells aren't attacked by virus, stops production of protein so viruses can't replicate, induces viral infected cells to be attacked by T cells

Natural Killer (NK) Cells

Cells that recognize and destroy infected or cancerous cells non specifically using granzyme and perforin

Complement system

A group of about 30 blood proteins that may amplify the inflammatory response, enhance phagocytosis, or directly lyse extracellular pathogens.

Lysozyme

Enzyme that breaks down bacterial cell walls found in body fluids like tears and saliva

How do resident microbiota help with immunity?

These microbes are competition for invading pathogens and discourage them from colonizing

Mast cells

Cells that detect damage in the tissue and release cytokines and histamine

Cytokines

Signaling proteins that stimulate immune responses.

inflammation

a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection.

Diapedsis

The ability of white blood cells to move in and out of blood vessels into tissue.

Neutrophils

A type of white blood cell that engulfs microbes by phagocytosis

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Apoptosis

process of programmed cell death

pus

A fluid created by infection made of dead white blood cells

How do cytokines communicate to the immune system?

Neutrophils follow a trail of them to the infection site (positive chemotaxis)

What makes neutrophils ideal for early defense?

They can move fast and die fast. Microbes do not have time to hijack them.

Macrophages

Amoeboid cells that roam connective tissue and engulf foreign particles and debris of dead cells.

What do macrophages do with dead microbes?

They present them to T-cells in the lymph node (antigens)

Besides macrophages, what cells can present antigens?

Dendritic cells and B-Cells.

MHC II stands for

Major Histocompatability Complex II

MCH II

Antigen presenting cells use this to present exogenous microbes to Helper T cells (CD4+)

CD4

coreceptor on helper T cells that accepts antigens from MHC II

T helper cells

lymphocytes with CD4 receptors on their cell-surface membranes.

Activated T-helper cells

-Activate B cells to induce antibody production

-release cytokines to help activate cytotoxic T cells

Plasma cells

Cells that develop from activated B cells and produce antibodies only against antigen they are programmed for

Adaptive Immunity

the ability to recognize and remember specific antigens and mount an attack on them

Fab region of antibody

part of the antibody that binds to the antigen

Fc region of antibody

The constant portion of the antibody that may bind to immune cell receptors on macrophages, neutrophils, and mast cells

Antibody

a substance produced by the body that destroys or inactivates an antigen that has entered the body

Antigen

substance that triggers an immune response

IgG

produced by plasma cells and memory cells against subsequent infections

Immunoglobulins

bind with specific antigens in the antigen-antibody response

IgA

Found in mucous, saliva, tears, and breast milk. Protects against pathogens

IgE

Protects against parasitic worms. Responsible for allergic reactions

IgM

May be attached to the surface of a B cell or secreted into the blood. Responsible for early stages of immunity.

IgD

Part of the B cell receptor. Activates basophils and mast cells

CD8+ Cytotoxic T cells

use granzyme and perforin to kill virally infected cells by forcing it to apoptosis

granzyme

an enzyme that induces programmed cell death (apoptosis)

perforin

a protein, released by killer cells of the immune system, that destroys targeted cells by creating lesions like pores in their membranes.

Dendritic cells

specialized white blood cells (phagocytes) that destroy microbes

B cells

Lymphocytes that produce antibodies when activated by T-cells.

First line of defense

innate barriers to antigen like intact skin, mucous membranes and their secretions, normal microbiota

Second line of defense

nonspecific internalized system of protective cells inflammation and phagocytosis. innate immunity.

Third line of defense

adaptive response that occurs later after encountering pathogen.

innate immunity

Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens.

lymphatic system

Composed of a network of vessels, ducts, nodes, and organs. Provides defense against infection.

Spleen

An organ that is part of the lymphatic system; it produces lymphocytes, filters the blood, stores blood cells, and destroys old blood cells.

Thymus

Gland in the thoracic cavity above the heart. Second place T cells go after being made so they can mature.

Red Bone Marrow

produces red and white blood cells and platelets

Inflammation

a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection.

Skin as a defense against pathogens

cells are cemented together preventing infection, dead skin prevents microbes from attaching.

Mucus as a defence

- traps particles and bacteria entering airways

commensal bacteria as a defence

residents take up space and resources especially in portals of entry, discourage pathogen from colonizing

virome as a defence

bacteriophages infect bacteria including potential pathogens

Artificially Acquired Active Immunity

Antibodies are forced to be made by the body by intentionally stimulating it eg vaccine

Artificially acquired passive immunity

Antibodies gathered from a human or other animal and are injected into an individual. Ex.) immune serum

Naturally acquired passive immunity

Antibodies are passed from mother to fetus via the placenta and breast milk

naturally acquired active immunity

antibodies made due to direct exposure to an antigen

active immunity

A form of acquired immunity in which the body produces its own antibodies against disease-causing antigens.

passive immunity

Immunity conferred by transferring antibodies from an individual who is immune to a pathogen to another individual.

attenuated vaccine

vaccine composed of a weakened form of the pathogen that is generally unable to cause disease

Inactivated vaccine

vaccine composed of killed bacterial cells, inactivated virus, or fractions of the pathogen

Conjugate vaccine

specialized immunizations that chemically link a weak bacterial sugar coating (polysaccharide) to a strong carrier protein to trigger antibody production

Toxoid vaccine

a modified, harmless version of a bacterial toxin used to 'train' an immune response

Why are live attenuated vaccines not recommended for people with weakened immune systems?

There is a chance the weakened virus can still infect a weakened immune system

Tamiflu (oseltamivir) Mechanism of Action

Drug binds to host cell membranes and prevents flu virus from budding

Tamiflu used for?

Influenza A and B

What is the difference between a leukocyte and lymphocyte?

All lymphocytes are leukocytes but lymphocytes specifically reside in the lymph nodes.

MHC I

molecules found on every body cell that presents antigens from endogenic pathogens to CD8+ T cells. Healthy cells bind this to NK cells to signal they are not cancerous

CD8

A coreceptor present on most cytotoxic T cells, that binds to class I MHC molecules, enhancing the interaction between the T cell and a target cell.

memory b cells

remembers the antigens of its mother B cell to speed up immune process by bypassing antigen presentation and activation to antibody production (and increases antibodies created)

What cells are part of the innate immune response?

Natural killer cells, neutrophils, macrophages (from monocytes) or dentritic cells

What cells are part of the adaptive immune response?

Helper T cells, Cytotoxic T cells, B lymphocytes, Plasma cells, Memory B cells

Why is it helpful for the body to have 2nd and 3rd line of defense

Innate, 2nd line, is the immediate, nonspecific defense to stop the spread of pathogens. Adaptive, 3rd line, is the long lasting, antigen targeted specific defense to prevent reinfection.

Allergen

a substance that causes an allergic reaction

Histamine

Chemical stored in mast cells that triggers dilation and increased permeability of capillaries, causes symptoms like itching and swelling.

Sensitization

period before allergy symptoms where B cells erroneously create IgE for allergen from an APC and spread it to mast cells

antigen presentation in MHC 1 process

Virus enters cell -> biosynthesis of viral proteins -> MHC 1 picks up a piece of viral protein -> presents on outside of hijacked cell

antigen presentation in MHC 2 process

Antigen killed by neutrophils -> debris of dead antigen eaten by macrophage -> macrophage presents antigen with MHC 2

Why are dendritic cells considered important "bridge" cells between innate and adaptive immunity?

They are better at activating naive T cells faster than macrophages

Why is antigen presentation so important to T-cells?

T-cells cannot act without verification of MHC

Epitope

the part of an antigen that can be identified by the immune system and antibodies bind to

Why are memory cells important in later exposures to the same pathogen?

By recognizing the pathogen earlier and not waiting for presentation, it can release more antibodies faster than the first time

Beta-lactam antibiotic targets

targets bacterial cell wall production

Beta-lactam examples

penicillins, cephalosporins, carbapenems

Beta-lactam effective against

broad spectrum but more effective against gram +

Aminoglycosides target

targets ribosomes -> inhibits protein synthesis -> inhibits overall growth

aminoglycosides examples

Gentamicin

Tobramycin

Amikacin

Streptomycin

Aminoglycosides effective against

Broad Spectrum equally

Fluoroquinolones target

Targets DNA synthesis

Fluoroquinolones examples

Ciprofloxacin

Levofloxacin

Moxifloxacin

Fluoroquinolones effective against

Broad spectrum

Sulfa targets

Targets metabolisms

Sulfa examples

Bactrim (sulfamethoxazole - trimopethrim)

Sulfa effective against

Broad spectrum

Penicillins are isolated from

Fungi

Tetracycline

Not a true aminoglycoside by inhibits ribosomes

Cipro mechanism of action

inhibits DNA replication by destroying DNA gyrase

Bactrim, Septra, sulfamethoxazole mechanism of action

competitively inhibits folic acid metabolism

Betalactamase

Enzyme produced by bacteria to destroy beta lactam rings of beta lactam antibiotics

Explain how bacteria become resistance to antibiotics?

Develop R-plasmids that then change genes to express antibiotic resistance