GPT Immunology Notes

Question 1

What are the primary lymphoid organs?

Answer 1

Bone marrow and thymus

Question 2

Where do B cells mature?

Answer 2

Bone marrow

Question 3

Where do T cells mature?

Answer 3

Thymus

Question 4

What happens in the thymic cortex?

Answer 4

Positive selection of T cells

Question 5

What happens in the thymic medulla?

Answer 5

Negative selection of T cells

Question 6

What are the secondary lymphoid organs?

Answer 6

Lymph nodes, spleen, MALT (tonsils, Peyer’s patches, appendix)

Question 7

Where are B cells located in lymph nodes?

Answer 7

Cortex (follicles)

Question 8

Where are T cells located in lymph nodes?

Answer 8

Paracortex

Question 9

What does the spleen’s white pulp contain?

Answer 9

Lymphoid tissue; PALS (T cells), follicles (B cells)

Question 10

What does the spleen’s red pulp do?

Answer 10

Filters blood and removes old RBCs

Question 11

What is MALT and its function?

Answer 11

Mucosa-associated lymphoid tissue; IgA production in mucosal surfaces

Question 12

Which cells are part of the innate immune system?

Answer 12

Neutrophils, macrophages, dendritic cells, NK cells, mast cells, eosinophils, basophils

Question 13

Which cells are phagocytic?

Answer 13

Neutrophils and macrophages

Question 14

Which cell links the innate and adaptive immune systems?

Answer 14

Dendritic cells

Question 15

What is the function of NK cells?

Answer 15

Kill virus-infected and tumor cells using perforin and granzymes

Question 16

Which cells are involved in allergic reactions?

Answer 16

Mast cells, basophils, eosinophils

Question 17

What do eosinophils combat?

Answer 17

Parasites and mediate allergic responses

Question 18

What is the function of CD4+ T cells?

Answer 18

Helper cells that activate B cells, macrophages, and other immune cells

Question 19

What is the function of CD8+ T cells?

Answer 19

Cytotoxic T cells that kill infected or abnormal cells

Question 20

What is the function of B cells?

Answer 20

Produce antibodies and present antigens

Question 21

Which T helper subset activates macrophages and is involved in intracellular immunity?

Answer 21

TH1

Question 22

Which T helper subset is involved in extracellular immunity and parasite defense?

Answer 22

TH2

Question 23

Which T helper subset is involved in fungal defense and autoimmunity?

Answer 23

TH17

Question 24

Which T cell subset is responsible for immune tolerance?

Answer 24

T regulatory cells (Tregs)

Question 25

What are PRRs and what do they recognize?

Answer 25

Pattern Recognition Receptors; recognize PAMPs

Question 26

What cytokines are released during innate immune response?

Answer 26

TNF-α, IL-1, IL-6

Question 27

Which cells present antigens via MHC I?

Answer 27

All nucleated cells

Question 28

Which cells present antigens via MHC II?

Answer 28

Professional APCs (dendritic cells, macrophages, B cells)

Question 29

Which MHC class interacts with CD8+ T cells?

Answer 29

MHC I

Question 30

Which MHC class interacts with CD4+ T cells?

Answer 30

MHC II

Question 31

What are the three signals needed for T cell activation?

Answer 31

1. TCR + MHC-antigen, 2. Costimulation (CD28-B7), 3. Cytokines

Question 32

What types of B cell activation exist?

Answer 32

T-independent (non-protein antigens), T-dependent (protein antigens + CD4+ help)

Question 33

What happens during T-dependent B cell activation?

Answer 33

Class switching, affinity maturation, memory B cell generation

Question 34

What is the most abundant antibody in circulation?

Answer 34

IgG

Question 35

Which antibody crosses the placenta?

Answer 35

IgG

Question 36

Which antibody is predominant in mucosal surfaces?

Answer 36

IgA

Question 37

Which antibody is produced first in a primary response?

Answer 37

IgM

Question 38

Which antibody is associated with allergies and parasitic infections?

Answer 38

IgE

Question 39

What is the role of IgD?

Answer 39

Function unclear; found on naive B cells

Question 40

What are the three complement pathways?

Answer 40

Classical, alternative, lectin

Question 41

What activates the classical pathway?

Answer 41

Antigen-antibody complexes (C1q)

Question 42

What activates the alternative pathway?

Answer 42

Pathogen surfaces

Question 43

What activates the lectin pathway?

Answer 43

Mannose-binding lectin

Question 44

What are key functions of complement proteins?

Answer 44

C3b = opsonization, C5a = chemotaxis, MAC (C5b-C9) = cell lysis

Question 45

What is the difference between primary and secondary immune responses?

Answer 45

Primary = slow, IgM; Secondary = fast, IgG/IgA/IgE

Question 46

Where does central tolerance occur?

Answer 46

Thymus (T cells) and bone marrow (B cells)

Question 47

What mechanisms are involved in peripheral tolerance?

Answer 47

Anergy, suppression by Tregs, deletion

Question 48

What causes autoimmunity?

Answer 48

Failure of immune tolerance

Question 49

What are examples of primary immunodeficiencies?

Answer 49

SCID, DiGeorge syndrome, X-linked agammaglobulinemia

Question 50

What are examples of secondary immunodeficiencies?

Answer 50

HIV/AIDS, chemotherapy, malnutrition

Question 51

What is a type I hypersensitivity reaction?

Answer 51

IgE-mediated; allergies, anaphylaxis

Question 52

What is a type II hypersensitivity reaction?

Answer 52

IgG/IgM-mediated cytotoxicity (e.g., hemolytic anemia)

Question 53

What is a type III hypersensitivity reaction?

Answer 53

Immune complex deposition (e.g., SLE)

Question 54

What is a type IV hypersensitivity reaction?

Answer 54

T cell–mediated (e.g., contact dermatitis, TB test)