HRR: introduction to the immune system

Question 1

Generally, how does the immune system defend against extracellular/mucosal threats?

Answer 1

Soluble proteins and phagocytic cells

Question 2

Generally, how does the immune system defend against intracellular threats?

Answer 2

Specialized cells that kill each other via cell signaling or cell-cell contact

Question 3

List the 3 major components of the immune system

Answer 3

Leukocytes, lymphoid tissue, and secreted proteins

Question 4

What are the general functions of leukocytes in the immune system

Answer 4

They’re the weapons and soldiers of the immune system; they detect, neutralize, and eliminate various threats

Question 5

What are the general functions of lymphoid tissue

Answer 5

They’re the training camps and forts; the generate, support, and store leukocytes

Question 6

What are the general functions of secreted proteins

Answer 6

They’re the communicators and have a minor weapon role; they can activate systemic defenses, directly neutralize toxins, participate in cell-cell communication, and activate/coordinate/mature/differentiate leukocytes

Question 7

Where are most of the white blood cells found?

Answer 7

In lymphoid tissues!

Question 8

What are the primary lymphoid organs

Answer 8

Thymus and bone marrow

Question 9

What are the secondary lymphoid organs

Answer 9

Spleen, lymph nodes

Question 10

Compare the innate and adaptive immune responses in terms of speed

Answer 10

Innate immunity is much faster than adaptive immunity. Innate takes minutes to hours, while adaptive takes days to weeks

Question 11

Compare innate and adaptive immune responses in terms of memory

Answer 11

The innate immune system has no memory, meaning there is no improvement in response with subsequent encounters. The adaptive immune system has memory, meaning the immune response is faster and stronger with each subsequent encounter

Question 12

What are some innate defenses

Answer 12

Epithelial, chemical barriers, granulocytes, NK cells, and complement

Question 13

What are antigen presenting cells?

Answer 13

Cells in the innate immune system that spread out in tissues and monitor for threats; big examples include macrophages and dendritic cells

Question 14

Explain the difference between pathogen-and damage-associated molecular patterns (PAMPs and DAMPs) and antigens

Answer 14

PAMPS are molecules found in pathogens but not our cells, and DAMPs are molecules normally found inside the cell but instead are on the outside

Question 15

What components are recognized by the innate and adaptive immune systems to signal threats?

Answer 15

The innate immune system recognizes PAMPs and DAMPs, while the adaptive immune system recognizes antigens

Question 16

Briefly compare the cells of the innate and adaptive immune systems

Answer 16

The cells in the innate immune system are released from bone marrow fully functional and ready, and do not divide once out of the bone marrow. Cells of the adaptive immune system, proliferate and differentiate after encountering antigen before they are considered functional

Question 17

Explain the relationship between immature, mature, activated, effector and memory lymphocytes.

Answer 17

Immature: freshly made from hematopoietic stem cells

Mature naïve: has gained a unique antigen receptor, but has not encountered the antigen

Activated: the lymphocyte encounters the antigen and proliferates. Innate immune signals will allow for differentiation into specific effector lymphocytes. Memory lymphocytes will also be formed

Question 18

what are the two major effector mechanisms employed by the immune system to destroy infectious agents and abnormal cells?

Answer 18

antibodies and T cells

Question 19

describe T cells: what they do, how they do it, and what they’r effective against

Answer 19

• kill cells by touching them
• Its receptors recognize foreign antigen on a cell, perforin pierces it and allows T cell enzymes to enter the cell, and the cell destroys itself from the inside out.
• they’re effective against tumors and intracellular microbes.

Question 20

describe antibodies

Answer 20

made by B cells. They have 2 light and 2 heavy chains bonded by disulfide bonds. They have variable regions that stick to antigens and a constant region that can interact with leukocytes and innate soluble proteins.

Question 21

list the 5 different antibodies

Answer 21

IgG: phagocytes
IgM: complement
IgD: B-cell activating receptor
IgA: secreted into mucus
IgE: binds to mast cells and eosinophils

Question 22

What are plasma cells?

Answer 22

Cells in the bone marrow that are differentiated B cells. They make the same antibody for life, but do not respond to antigen

Question 23

How do antibodies protect us?

Answer 23

Activate complement, block bacteria and viruses from attaching to our cells (IgA in blood, IgM in mucus), opsonization (aka increased phagocyte capture and destroy abilities), activate eosinophils and basophils

Question 24

How can the innate immune system steer antibody production

Answer 24

the release of cytokines

Question 25

Explain the difference between passive and active immunity

Answer 25

Active immunity is when a person develops antibodies/T cells themselves after vaccine or infection. Passive immunity is when someone is injected with T cells or antigens. Active takes longer but lasts longer, while passive is fast but temporary

Question 26

describe humoral immunity

Question 27

describe cellular immunity

Question 28

what recognizes PAMPS in the innate immune system

Answer 28

pattern recognition sequences