Intro to immuno lect. 1

What are the 4 characteristics of the innate immune system?

1. Responds immediately

2. Nonspecific (Responds the same way to all pathogens)

3. Doesn’t create memory

4. a.k.a natural immunity

What influences the function/response of the innate immune system?

Age, stress, nutrition and fatigue, genetics

What WBCs are part of the innate system? What cells do they originate from?

Neutrophils, basophils, mast cells, monocytes, and eosinophils

• come from the common myeloid progenitor cell (CMP)

What do monocytes turn into when they move into tissue? If there is inflammation in the area, what do they turn into instead?

Macrophages → tissue

Dendritic → inflammation exposure

What % of monocytes are apart of WBCs?

4%-10%

Macrophages are monocytes that have migrated into tissues. What are Macrophages’ 3 functions in the innate system?

1. Phagocytosis → microbe & tumor cell killing

2. intracellular parasite killing

3. Secretes cell mediators

What % of Neutrophils are in WBCs and what is their main function?

50%-70%

Main function: Phagocytosis (due to digestive enzymes)

What can Neutrophils follow that leads them into tissue? An increase in neutrophils is a sign of what type of infection?

Chemotactic factors.

Bacterial infections.

What % of eosinophils are in WBCs and what are 5 of it’s functions?

1%-4%

1. Kills parasites (“shoots” granules at them)

2. Phagocytosis of small debris

3. Neutralizes basophil allergic products

4. Releases cytokines

5. Regulates mast cells

What % of basophils are in WBCs and what do they do?

<1%

• induces and maintains allergic responses (via histamines)

Where are mature mast cells located? What do they do? What are they?

located in tissues.

They cause allergic reactions and are APCs.

Dendritic cells come from the myeloid (innate) and the lymphoid (adaptive) progenitors. What do these cells do? (hint* 3 things)

1. Very effective phagocytes

2. Most effective APC

3. Initiates the adaptative response b/c it carries an antigen (innate task) to a T cell (adaptive task) in the lymph nodes.

What is adaptive immunity/what does it do?

• Creates memory (after 1st interaction it gets better, faster, stronger)

• Creates specificity for each new pathogen

• Reacts slowly when it meets a new pathogen

Adaptive immunity cells come from what cell(s)? What main cell type do they become? What 3 cell types are in this main cell type?

Come from common lymphoid progenitor cells.

Main cell type: Lymphocyte cell

3 sub types: T cell, B cell, and NK cell

What % of lymphocytes (adaptive immune system) are in WBCs? What differentiates them into T, B or NK cells?

20%-40%

The cluster differentiation (CD) markers on the lymphocyte cell places them into their subtypes.

Where is the B cell produced? What markers on this lymphocyte indicate it is a B cell?

Produced in bone marrow.

The markers: CD19, CD21, MHCII

What happens when the B cell interacts with an antigen? What is the marker for this cell and what does it produce?

It becomes a plasma cell and gains the marker: CD38+.

As a plasma cell, it produces a ton of antibodies.

Where does the T cell mature? This lymphocyte can become a helper T cell (Th), a regulatory T cell (RegT), or a Cytoxic T cell (Tc). What are their respective markers?

Matures in the thymus.

Th: CD3+, CD4+

RegT: CD3+, CD4+

Tc: CD3+, CD8+

What do T helper cells do? RegT? Cytoxic T (Tc)?

Th: helps B cells produce antibodies

RegT: inhibits immune response

Tc: Destroys tumor cells and virally-infected cells

Although the NK cells come from the lymphoid progenitor cells (adaptive system), it acts as an innate immune response. What are the markers for this lymphocyte cell and what does it do?

Markers: CD16+, CD56+

It destroys tumor cells and virally infected cells on contact (innate response) as well as antigen-coated cells.

What 3 cells (comes from lymphoid progenitor and myeloid progenitor cells) are specifically associated with being in tissue?

• Macrophages

• Dendritic cells

• Mast cells

What are the 2 primary lymphoid organs? What happens there?

1. Bone marrow → B cell maturation and main source of hematopoietic stem cells

2. Thymus → T cell maturation

What are the 4 secondary lymphoid organs? What do they receive and function as?

1. Spleen

2. Lymph nodes

3. Mucosal-associated lymphoid tissue (MALT)

4. Skin-associated lymphoid tissue (SALT)

All receive: Mature lymphocytes (B,T, and NK cells)

All sites function as: An interaction point for lymphocytes and foreign material

The spleen has red and white pulp. What cells can be found in the different pulps?

Red pulp: Macrophages → destroy old RBCs

White pulp: T cells in lymph sheath, B cells in follicles attached to lymph sheath

Lymph nodes are located around joints and limb attachment points. Where are B and T cells located within the lymph nodes?

B cells: Follicles in cortex

T cells: Paracortex

Within Mucosal lymph tissue (MALT), what cells are mainly found here and why?

Macrophages and lymphocytes (T, B, NK) b/c many antigens enter these locations (ex. respiratory, urogenital, appendix, peyer’s patches).

Within Skin lymph tissue (SALT), what cells are found here?

T cells, monocytes, and dendritic cells

Define immunology.

The study of the host’s reactions to foreign substances

Define “antigen” and “immunogen”.

Antigen: Particles that are recognized by the immune system, does not need to cause a response (ex. pollen)

Immunogen: A particle that always causes an immune response (ex. flu protein)

Define immunity.

Being resistant to an infection

Define attenuation. Who discovered this and what is his nickname?

attenuation: making a live pathogen weaker via heat or chemical treatment, or aging.

Discovered by Louis Pasteur, a.k.a the “Father” of immunology.

Edward Jenner was the first person to create what? What virus did he use?

Created the first “vaccine”. He used cowpox to create immunity to smallpox.

Where does the specific (adaptive) immune response to a foreign antigen mainly occur?

lymph nodes