Intro to Immunology

Question 1

What is innate Immunity?

Answer 1

Barriers to Infection.

1. Physical barriers (Epithelial and Mucosal surfaces)
2. Chemical barriers(The primary secreted compounds that are microbicidal are the antimicrobial peptides- lysozyme.)
3. Microbial/Biological barriers (Commensal microbes are called microbiota)
4. Cells of the Innate Immune System (Macrophages, neutrophils, dendritic, natural killer cells, eosinophils, basophils)

Question 2

What is adaptive immunity?

Answer 2

Immunity that uses antibodies and T cell activation.

Question 3

Which immune response is activated first during infection?

Answer 3

INNATE!

Question 4

What are some differing characteristics between innate and adaptive immunity cells?

Answer 4

Innate cells:
First to respond to infection (or injury)
Do not respond to a specific microbe
Not antigen specific (later we’ll say they’re not MHC restricted)

Adaptive immune cells
Respond later during infection
Respond to specific microbe (the specificity is the reason it takes longer for the response to develop)
Antigen specific cells (later we’ll say they are MHC restricted)

Question 5

What are some characteristics of eosinophils?

Answer 5

Eosinophils: play a prominent role in responses to parasitic infections (also involved in allergic reactions and asthma).
Recognition of IgE-coated parasite causes degranulation:
-eosinophil cationic protein
-major basic protein
-eosinophil peroxidase
-reactive oxygen and reactive nitrogen intermediates.

Question 6

What are some characteristics of neutrophils?

Answer 6

Primary function of the Neutrophil is to kill bacteria. Have some effects against larger extracellular pathogens as well. Can produce cytokines, but does not present antigen.

Have a multi-lobed nucleus. Are attracted to sites of infection by multiple signals including bacterial products.
Have a high density of granules that contain a variety of microbicidal enzymes, such as lysozyme and defensins.

Question 7

What are some characteristics of macrophages?

Answer 7

Highly phagocytic cells that contain enzyme-rich granules. But, the density of granules is far less than in neutrophils.

Macrophages have 3 important functions. To kill microbes and to present antigen to cells of the adaptive immune system. In addition, macrophages are prolific cytokine producers.

Question 8

What are some characteristics of dendritic cells?

Answer 8

Dendritic Cells: Phagocytic cells (less predominant than neutrophils, monocytes/macrophages) are primarily responsible for phagoytosing microbes, and presenting peptide antigens to lymphocytes. Thus, they are generally referred to as antigen presenting cells (or professional antigen presenting cells).

The dendritic cell is the principal cell type that links the innate immune response to the adaptive immune response (macrophages can do this too)
	Cytokine Producers
	Phagocytic Cells (but more specialized toward 	antigen 	presentation).

Question 9

What are some characteristics of natural killer cells?

Answer 9

Natural killer (NK) and lymphokine activated killer (LAK) cells – NK and LAK cells can nonspecifically kill virus infected and tumor cells. 
important in nonspecific immunity to viral infections and tumor surveillance.

Question 10

What immune cells are phagocytes?

Answer 10

macrophages, neutrophils, dendritic cells

Question 11

What immune cells are antigen presenting cells?

Answer 11

macrophages and dendritic cells.

Question 12

What cells are granulocytes?

Answer 12

Neutrophils, eosinophils, basophils, mast cells.

Question 13

Which cells are lymphocytes?

Answer 13

B cells and T cells and NK cells

Question 14

Which cells are leukocytes?

Answer 14

Neutrophils, eosinophils, basophils, macrophages, b and T cells

Question 15

What is an antigen?

Answer 15

An antigen (Ag) is any substance that can be specifically bound by a cell of the adaptive immune system

Question 16

Types of antigens

Answer 16

Immunogen- an antigen that elicits an immune response
Tolerogen- induces immunological tolerance or immune non-responsiveness
Allergen- an antigen that causes an immediate hypersensitivity (allergic) reaction

Question 17

What is meant by pathogen associated molecular pattern?

Answer 17

Unique structures on microbes (which often involve repeated motif’s/structures) are referred to a pathogen associated molecular patterns (PAMPS).

Question 18

Know what is meant by pattern recognition receptors.

Answer 18

The innate immune system uses pattern recognition receptors (PRR) to recognize PAMPS.

Question 19

Important PRR’s on innate immune cells (phagocytosis)

Answer 19

N-formyl-methionyl receptor.
Mannos receptor.
Scavenger receptor.

Question 20

What are Toll-like receptors?

Answer 20

Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system as well as the digestive system. They are single, membrane-spanning, non-catalytic receptors usually expressed in sentinel cells such as macrophages and dendritic cells, that recognize structurally conserved molecules derived from microbes. Once these microbes have breached physical barriers such as the skin or intestinal tract mucosa, they are recognized by TLRs, which activate immune cell responses.

They are a type of pattern recognition receptors.

Question 21

Where are Toll like receptors located?

Answer 21

On or In immune cells such as macrophages and dendritic cells.

Question 22

Why are Toll-like receptors located intracellularly?

Answer 22

These detect viruses.