Venketaraman- Host Defenses

Question 1

innate immunity cells are pre-formed, and non-specific. but is it true/false that they lack immunological memory and do not improve over time?

Answer 1

true

Question 2

what type of innate defense cell is non-phagocytic?

Answer 2

natural killer cells

Question 3

which type of immunity (innate or adaptive) is slower onset but is highly effective once active?

Answer 3

adaptive immunity

Question 4

do T lymphocytes produce antibodies and immunoglobulin?

Answer 4

no… they produce cytokines and interleukin

Question 5

what antigen do dendritic cells contain on their surface?

Answer 5

CD14

Question 6

what type of cell is capable of phagocytosis and pinocytosis?

Answer 6

Dendritic cells

Question 7

what type of immunity presents antigens to CD4-positive helper T cells?

Answer 7

acquired immunity

Question 8

what three things are generated when microbes are phagocytosed by monocytes and neutrophils?

Answer 8

reactive oxygen and nitrogen intermediates and antimicrobial peptides

Question 9

when does fusion between phagosome containing microbes with lysosome occur?

Answer 9

when monocytes and neutrophils carry out phagocytosis

Question 10

Complement proteins are mainly inactive in the blood. What leads to their activation?

Answer 10

antigen-antibody reactions, release of lipopolysaccharide (LPS) or release of mannose (carbohydrate)

Question 11

what is the classical pathway of antigen-antibody reactions?

Answer 11

leads to the complex binding to the bacterial cell surface causing lysis of the bacteria

Question 12

what pathway leads to the release of LPS from gram negative bacteria?

Answer 12

alternate pathway

Question 13

Which cells phagocytotic activity are enhanced by the interaction of complement proteins with antibodies? And what is the process called?

Answer 13

neutrophils and monocytes.

opsonisation

Question 14

in order of natural killer cells to lyse their target what needs to down regulated on the target?

Answer 14

MHC class I

Question 15

what is the purpose of Toll like receptors (TLRs)?

Answer 15

they recognize LPS (TLR4) from gram negative bacteria and peptidoglycan (TLR2) from gram positive bacteria

Question 16

what is the purpose of pro-inflammatory cytokines?

Answer 16

to induce liver cells to produce C-reactive proteins and also attract cells to site of infection leading to inflammation and cell death

Question 17

Do T cells differentiate in the bone marrow?

Answer 17

nope… they differentiate in the thymus

Question 18

what are the three steps in adaptive immunity (T cell response)?

Answer 18

antigen recognition, activation and response

Question 19

both antigens and haptens are able to bind to antibodies, but which one cannot produce antibodies independently (without carrier protein)?

Answer 19

haptens

Question 20

Do all T cells express CD4?

Answer 20

No, they all express CD3. (CD4 is only expressed by helper T cells)

Question 21

What produces cytokines like interferon-gamma that can activate macrophages and neutrophils to control intracellular infrection?

Answer 21

Helper T cells

Question 22

what type of T cell binds to dendritic cells in association with MHC I?

Answer 22

cytotoxic (CD8) T cells. these cells lead to cell lysis

Question 23

What causes B cells to produce IgM?

Answer 23

Binding of LPS and other non-protein antigens to IgD on the surface of the B cells