06 Innate Immunity 2

Eosinophil function

Fights worms, wheezes, and weird diseases (parasites, allergies, and some other random stuff)

Types of proteins present in eosinophil granules

• Basic protein

• Cationic protein

• Peroxidase

Types of lymphocytes that straddle the border between innate and adaptive

Natural killer cells and γδ cells

How do NK cells differ from normal, adaptive lymphocytes

They lack the expression of antigen receptors

How is NK cell target recognition different than other lymphocytes

They don’t recognize specific pathogens, but instead sense changes in the tissues

Types of cells targeted by NK cells

• Virus infected cells

• Cancer

• Cells with intracellular protozoa or bacteria

• Distressed/old cells

What cytokines activate NK cells

• IFN-α

• IFN-β

• IL-12

• TNF-α

Where do IFN-α and IFN-β come from

Cells infected by viruses will recognize the viral NAs and start pumping out cytokines

Where do IL-12 and TNF-α come from

Macrophages

NK cell natural cytotoxic receptor

Recognize natural cytotoxic proteins, which are expressed by stressed or infected cells

NK cell Ly49 receptor

Recognizes MCH-I molecules, which are expressed during infection

NK cell CD16 receptor

Recognizes cells that have been tagged by antibodies

Last type of NK cell receptor

Recognizes when cells are abnormally down regulating MHC-I, which is often caused by viruses and cancers

Which receptor is an activating receptor on an NK cell

Natural cytotoxic receptor

Which receptor is an inhibitory receptor on an NK cell

MHC recognizing receptors

Which type of receptor sets the rules (takes precedence)

Inhibitory

How do CD16 receptors on NK cells function

They bind to antibodies that have tagged an infected cell, and signal an apoptotic pathway in the cell

Apoptotic pathway signaled by CD16 receptors on NK cells

Perforin-granzyme pathway

Perforin mechanism of action

Poke holes into the cell membrane

Granzyme mechanism of action

Binds to cell death proteins to induce apoptosis

Once NK cells are activated, what is secreted

IFN-γ

What other cells produce IFN-γ

Helper T cells

IFN-γ function

Activates macrophages to secrete cytokines and to phagocytose

How are γδ T cells different from normal T cells

They have a variable TCR that recognizes a limited array of pathogens

How are γδ T cell TCRs different from normal TCRs

They are made from γδ proteins, and normal ones are made of αβ

How are γδ T cells beneficial compared to normal T cells

Recognizes nonprotein antigens (lipids, glycolipids, and lipoproteins (in non-native state)

What presenting molecule are the non-protein substances on that γδ T cells recognize

CD1 (analogous to MHC)

POLYREACTIVE ANTIBODIES