Immunology Fall 2022 (through midterm)

What are the three lines of immune defense

Physical barrier, innate immunity, adapative immunity

What is the purpose of the physical barrier?

to deter and delay

What is the biggest difference between innate and adaptive immunity?

MEMORY and speed

Explain adaptive immunity in terms of speed and specificity

slow but specific

Explain innate immunity in terms of speed and specificity

rapid but no specificity or improvements

What are some examples of physical barriers?

cilia, skin, lysozomes in tears

What are the key players of the innate immune system?

Natural killer cells, lymphocytes, dendritic cells, neutrophils, monocytes/macrophages, eosinophils, basophils

What are the key players of the adaptive immune system?

T and B cells

What bridges innate and adaptive immunity?

Dendritic cells

What is humoral adaptive?

Adaptive immunity using antibodies to fight extracellular invaders

What is cell-mediated immunity?

adaptive immunity using antibodies to fight intracellular invaders

What is MOST important about neutrophils?

First phagocytic cell to attack and destroy invading bacteria

What do neutrophils use to destroy bacteria?

hydrogen peroxide, hypochlorite, bactericidal granules, lactoferrin

What is extravasation?

The process of neutrophils being recruited for inflammation

What cell is involved in extravasation?

neutrophils

What are the two receptors aiding in extravasation?

Selectin and integrin

What type of selectin is on the epithelium?

P-selectin

What type of selectin is on the neutrophil?

L-selectin

What type of integrin is on the endothelium?

ICAM-1

What type of integrin is on the neutrophil?

LFA1

What is the job of selectins in extravasation?

to slow the neutrophil to a roll

What is the job of integrins in extravasation?

to cause adherance so they squeeze through the vessel wall

If a bacterium is large, how do neutrophils help?

NETosis

What is netosis?

Neutrophils release a large extracellular trap that is sticky to trap the bacterium and kill it without ingestion

What is the first phagocytic cell to attack and destroy bacteria?

Neutrophil

What is the first line of defense against a virus or tumor?

Natural killer cells

What do natural killer cells use to kill viruses and tumors?

Perforin and ganzymes

What do monocytes differentiate into?

Macrophages

What are the two types of macrophages?

M1 and M2

What are M1 macrophages?

destructive macrophages

What are M2 macrophages?

tissue repairing macrophages

What innate immune cells are responsible for allergies?

Mast cells, eosinophils, basophils

What is a phagosome?

Fusion of cell membrane around microorganism (ingested)

What is a phagolysozome?

fusion of phagosome and lysozome

What are the five types of dendritic cells?

Langerhans, plasmocytoid, follicular DC, Classical DC1, Classical DC2

What two dendritic cell types are vital for antibody production?

Follicular DC and Classical DC2

What are Follicular DC and classical DC2 vital for?

anitbody production

What are langerhans dendritic cells?

Found in skin, use Birbek granules

What are Plasmocytoid and classical DC1 vital for?

inhibiting viral replication

What two dendritic cell types inhibit viral replication?

Plasmocytoid and classical DC1

If dendritic cells are overwhelmed, who is called in for help?

Complement proteins

How do complement proteins work?

They attach to an invading cell, forma pore, and destroy it via osmotic lysis.

What special process allows complement proteins to work?

C9 polymerization

What are the three pathways of complement proteins?

Innate, alternate, and classical

What is the innate pathway of complements triggered by?

MBL (mannose-binding lectin) binding to a microbe

What is the alternate pathway of complements triggered by?

C3b binding to a microbe

What is the classical pathway of complements triggered by?

antibody secretion

What is the complement C3e responsible for?

promoting leukocytosis

What complements are made by the liver?

C3, C6, C8, FB (3 shots, 6 shots, work in 8 hours, Bad for liver)

What complements are made by mast cells?

C1q

What complement cells are made by neutrophils?

C6,C7

What complements are made by macrophages?

C2, C3, C4, C5, FP, FD, FI, FB (pinching dogs is bad)

What is a PRR?

Pattern recognition receptor. Found on all host innate immune cells to detect PAMP and DAMP

What is PAMP?

Pathogen Associated Molecular Protein. Produced by pathogens

What is DAMP?

Damage Associated Molecular Protein. Produced by invaded cell.

What is the major type of PRR?

TLR (Toll-like receptor)

Where are TLR found?

Intracellular for viruses and extracellular for bacteria

What does TLR-4 do?

targets LPS

What does TLR-5 do?

targets flagellum

When a PRR comes into contact with a PAMP what happens?

Inflammation

When a PRR comes into contact with a DAMP what happens?

inflammation

When a PRR comes into contact with a PAMP and a DAMP what happens?

Inflammation

What does inflammation caused by a PRR and PAMP and/or DAMP lead to?

Cytokine production

What is produced by macrophages and dendritic cells?

Cytokines

What are the cytokines specific for inflammation?

IL-1, IL-6, TNF alpha, IFN gamma

What are the three routes of cytokine binding?

Autocrine, paracrine, endocrine

What is autocrine binding of cytokines?

the cytokines bind to the same cell that released them

What is paracrine binding of cytokines?

The cytokines bind to neighboring cells

What is endocrine binding of cytokines?

the cytokines travel long distances via the blood stream to bind to cells

What are the four types of cytokines?

interferons, interleukins, TNF, chemokines

What is the job of chemokines and the most important chemokine?

to attract neutrophils for extravasation by CXCL-8

How do Humera and Enbrel work?

These drugs inhibit TNF receptors to decrease inflammation in diseases like Rheumatoid Arthritis

Explain the steps of signal transduction

1. cytokine binds ton receptor
2. kinase activation
3. second messengers activated
4. generation of new transcription factors
5. gene activation/ modification of cell behavior

What is signal transduction?

an extracellular signal being transformed into an intracellular signal

What are the two antigen-presenting structures?

MHC class 1 and MHC class 2

What is MHC class 1?

Used on NON-immune cells to alert to INTRACELLULAR/ENDOGENOUS invader

What is MHC Class 2?

Found on host immune cells after they have captured and processed the antigen. They degrade the antigen and create an MHC complex that is transported to cell surface

Where must MHC class 2 receptors be transported to in the body to present to B cells?

Lymphoid organs

What are the two types of lymphoid organs?

Primary and secondary

What are the primary lymphoid organs?

Thymus, bursa/bone marrow/intestinal lymphnoid tissue

What are the secondary lymphoid organs?

lymph nodes and spleen

What is the job of primary lymphoid organs?

to produce B/T cells and train them

What is the job of secondary lymphoid organs?

help with antigen presentation

What occurs in the thymus?

production of T cells

What occurs in the bursa/bone marrow/ intestinal lymphoid tissue?

Production of B cells

What occurs in the lymph nodes?

dendritic cells present to T cells in medulla

What is the spleen responsible for?

filtering antigens from blood

What are the two types of lymphocytes?

T and B cells

Where do T and B cells mainly reside?

lymph node and spleen

Can lymphocytes be differentiated on a histologic slide?

NO because they are all the same size/shape

How can we differentiate lymphocytes?

cytometry

What is a CD?

Marker on lymphocyte for identification (in addition to PRR and TCR/BCR)

What does CD stand for?

Cluster of differentiation

What are the two CD categories?

CD or WC

What is a WC CD?

A cluster of differentiation found only in one species (no homolog)

What is often the CD homolog for humans?

mouse

What is the purpose of a CD?

to help us identify the lymphocyte

How do adaptive immune cells recognize bacteria and viruses?

antigens

What are the two types of antigens?

immunogens and haptens

What are immunogens also called?

complete antigens