Med Micro 5 - Specific Defense Part 1A

Question 1

What is adaptive immunity?

Answer 1

ability to recognize and defend itself against distinct invaders and their products; “memory” allows it to respond rapidly to a second encounter with a pathogen

Question 2

Does the lymphatic system have a roll in innate immunity?

Answer 2

Yes. It is a one way system, so pathogens are likely to end up there. Concentrations of macrophages will probably deal with it (cells for adaptive immunity present too)

Question 3

What is the real value of adaptive immunity?

Answer 3

More specific, so more effective, and faster the second time around.

Question 4

Taking two weeks to respond is almost hopeless. What evidence is there for this?

Answer 4

We can look for ABs. We can use vaccines to generate this prior to seeing the antigens

Question 5

Circadian rhythm and immune system

Answer 5

Can affect infection. Number of eosinophils varies throughout the day. Bacteria vary with time as well. Antibiotics need to consider this. Study showed amount of TLR-9 varied with time and immune response was best at peak of TLR-9 expression

Question 6

Why is it so important to immunize at the peak of TLR-9 activity?

Answer 6

Phagocytes recognize, then play a role in antigen presentation. The vaccine will be cleared by other organs so the immune response will decrease quickly.

Question 7

5 elements of adaptive immunity

Answer 7

Mostly in lymphatic system; Specificity (but some cross reactivity with similar proteins), Inducibility (2 weeks first time, 3-4 days after), Clonality (make clones of B and plasma cells), Unresponsiveness to self, Memory

Question 8

Clonality and B cell

Answer 8

Have all same receptors (basically bound AB); genetically different from other B cells; when it gets induced, it will make many many copies of itself

Question 9

Summary of lymphatic system

Answer 9

B lymphocyte grows in red bone marrow; T lymphocyte begin in bone marrow then mature in thymus; both get concentrated in lymph nodes

Question 10

Age for healthy thymus

Answer 10

Max around 20. Decreases thereafter, don’t have a good T cell response (so more susceptible to viruses)

Question 11

General function of lymphatic system

Answer 11

Screens the tissues of the body for foreign antigens (acts like a net). Goal as always is to contain infection.

Question 12

Parts of lymphatic systems

Answer 12

Composed of lymphatic vessels and lymphatic cells, tissues, and organs which are directly involved in adaptive immunity

Question 13

Describe Lymph

Answer 13

Similar to blood plasma, Move from capillaries to larger vessels, Is a one way system

Question 14

Functions of lymph

Answer 14

Carries fats, Production of reactive immune cells, Removes excess liquid from cells and return to blood

Question 15

Important lymph nodes areas

Answer 15

Inguinal, axillary (armpit), cervical (neck), Mucosa-associated lymphatic tissue (MALT - around intestines - common infection site)

Question 16

Circulatory system

Answer 16

Includes the cardiovascular and lymphatic system. It’s a closed system. As it cycles, anything can be trapped (most infections don’t get to the blood due to lymphatic system)

Question 17

Septicemia

Answer 17

Aka sepsis; infectious pathogens are in the blood.

Question 18

Toxemia

Answer 18

Toxins are in the blood

Question 19

Spleen

Answer 19

Major concentration of adaptive immunity cells, screens blood.

Question 20

Lacteal

Answer 20

Like a capillary of the lymph system. Found all over, and in villi of GI tract.

Question 21

Organs of lymphatic system

Answer 21

Primary organs include the red bone marrow and thymus, Secondary organs include lymph nodes, spleen, and other less organized accumulations of lymphoid tissue like MALT, appendix, tonsils. The defense battles really take place in the secondary organs

Question 22

Relative organization of secondary lymph organs

Answer 22

Least: 3. Diffuse assemblages of lymphocytes and macrophages (in lung and intestinal wall) referred to as MALT and GALT. 2. Lymphoid follicles surrounded by draining lymph vessels. 1. Lymph nodes and spleen

Question 23

Specific screening by lymphoid organs

Answer 23

loose lymphoid tissue screens mucosal surfaces, the spleen screens the blood, and the lymph nodes screen tissues

Question 24

Lymphoid follicle

Answer 24

Many in a lymph node; Contain a high concentration of lymphocytes; The number and composition can change in the presence of an antigen (can actually swell in your neck)

Question 25

Lymph nodes

Answer 25

Filters lymph and houses leukocytes/lymphocytes which survey the lymph for foreign molecules.

Question 26

Can we generate an adaptive immune response if the bacteria never leave the injured region?

Answer 26

Adaptive immunity is inducible by 1st and 2nd line; antigen presenting cells can travel to the lymph nodes

Question 27

What happens in lymph node when antigen presentation occurs?

Answer 27

initial activation of B cells in germinal centers; within 4-7 days, a few B cells and TH cells migrate to 1° follicles of cortex to form 2° follicles

Question 28

Flow of fluid into and out of lymph node

Answer 28

afferent lymphatic vessel into germinal centers, screened, and out through efferent vessel

Question 29

Maturation

Answer 29

Differentiates to become a B cell, then further differentiation to become plasma cell

Question 30

Spleen

Answer 30

Similar in structure and function to the lymph nodes, Filters bacteria, viruses, toxins, and other foreign matter from the blood, Major role in immune response to Ag’s in blood

Question 31

Tonsils and MALT

Answer 31

Physically trap foreign particles and microbes, MALT includes the appendix, lymphoid tissue of the respiratory tract, and Peyer’s patches in the wall of the small intestine; huge surface area, major sites of entry

Question 32

M cells

Answer 32

Specifically associated with lymphatic system. Endocytose antigens on mucosal surface, bring antigens across mucous and deliver to dendritic cells (keeps phagocytes activated)

Question 33

Bacterial subversion - shigella

Answer 33

Stimulate endocytosis by M cell; presented to phagocyte and phagocytosed, but blocks phagosome-lysosome fusion and multiplies, kills phagocyte, and enters epithelial cells by stimulating endocytosis again on basal side, moves by polymerizing actin and pushes through membrane. Must cross first, cannot enter from outside. Intracellular pathogen.