Aspects of the Immune Response

Question 1

Functions ascribed to the various subsets of T cells

Answer 1

cooperation with B cells to enhance the production of antibodies (Th cells)

secretion of cytokines

Question 2

lymphokines

Answer 2

cytokines released by lymphocytes

Question 3

What happens once a T cell is activated (T helper)// Tdth

Answer 3

release cytokines that induce the migration and activation of monocytes and macrophages leading to the delayed hypersensitivity inflamaotry reactions

Question 4

What happens once a CTL is activated

Answer 4

become killer cell that upon contact with their proper ligand=antigen, cytokines and co-stimulation kill the target

Question 5

Th1

Answer 5

CD4+

intracellular mediated immune resposne

secrete IL-12, IFHg and TNFa

pro inflammatory

evoke cell-mediated immune responses

Question 6

Th2

Answer 6

CD4+

extracellualr parasites

secrete IL-4, IL-5 and IL-10

anti inflammatory and evoke a humoral immune response

helminths

Question 7

Th0 naive T cell

Answer 7

may differentiate into a helper Th cell when exposes to
proper nature of the antigen, does of antigen, the organ of initial antigen exposure and the cytokine milieu

teh cytokine milieu in whihc antigen presentation occurs is the most important determinant

Question 8

IL-12 / IL-10 Th differentiation bias

Answer 8

early production of IL-12 in the immunological synapse between APC adn the Th0 cell has been shown to prime Th1 responses in response to to intracellualr microbial infections and the secretion of IL-10 to biase Th2 T cell responses

Question 9

Mycobacteria

Answer 9

protective immunity mediaated by Th1 CD4+ T cells with the aid of other types of T cells

Th1 cells produce IFNg and TNFa in response to mycobacterial antigens

which are critical for macrophage activation and control of bacterial replicaiton

Question 10

cell-to-cell contact between T cells and antigen-presentign cells is an importnat event for the induciton of the tcell mediated immune response

Answer 10

indeed interaction of co-stimulatory and co-inhibitory receprots like CD-028 and CTLA-4 expressed on T cells the the ligands B7-1 and B7-2 on APC influences the magnitude and duration of antigen-specific T-cell response

Question 11

PC-1 expression

Answer 11

programmed cell death 1 (PD-1 = CD279) is a new member of the CD28/ CTLA-4 receptor family

PD-1 expression is induced on activated T cells and B cells and its constitutive

Question 12

imbalance in costimulatory ligands

Answer 12

can results in an inefficient adaptive immune response to clear infection, and may contribute to pathological consequences

Question 13

Brucella abortus

Answer 13

zoonotic Gram negative pathogen

in ruminants causes abortion and infertility

in humans causes undulant fever, characterized by malaise, aches and fevers

human brucellosis can be contraced by accidental contaminaiton form infected animals, handling infected tissues or sonsuming undercooked meat or unpasteurized dairy products from infected animals

Question 14

Brucella facultative intracellualr bacterial pathogenesis

Answer 14

pathogensis and the nature of the protective immune response are closely related to this property

both antibody and cell mediated immune responses (CMI) can influence the course of infection with brucella

CMI essential for clearance of intracellualr bacteria

thus, IFNg plays a central role in aquired resistance agaisnt Brucells

upregulated macrophage microbial killing

Question 15

Type I allergy

Answer 15

The mechanism of the pathogenesis of Type I allergy is initiated by phagocytosis of allergens by APCs

the balance between Th1 and Th2 dominant immunity is thought to be important here as well

Question 16

Prominent systemic manifestations of inflammation

Answer 16

elevation of body temperature and variety of biochemical alterations known as the acute phase reaction which leads to the synthesis of acute phase protiens in the liver

Question 17

The local infflammatory reaction is characterized by

Answer 17

an initial increase in blood flow to the site of injury

enhanced vascular permeability = more flow of WBCs

influc of antigen non-specific cells and highly destructive cells= neutrophils is one of the earliest stages of the inflammatory response
=> these cells mount a rapid, non-specific response

after, moncytes, macrophages and lymphocytes Bs and Ts appear at the site on injury

these cell types are associated with antigen-specific and more tightly regulated immune responses

Question 18

inflammatory cells

Answer 18

express more cell-surface proteins and glycoproteins known as cell adhesion molecules

Question 19

endothelial cells

Answer 19

are also activated during initial phase of the inflammatory response and then express, among other things, adhesion molecule counterreceptors

Question 20

immune cell mediators

Answer 20

dound in the serum or tissu eof sluids, are released by degranulating cells upon activation , or activated endothelial cells in blood vessels at the site of inflammation

they serve as muscle-active and edema-promoting substances, chemotaxins, and cellular activators and inducers of all kinds of effector cells engaged in the inflammatory response

Question 21

Types of inflammatory mediators

Answer 21

kinins of the coagualtion system

leukotrienes

prostaglandins

other lipid mediators

Question 22

Acute phase proteins

Answer 22

a class of proteins whose plasma concentrations increase or decrease (positive or negative respectivly) in response to inflammation.

Question 23

Secretion of cytokines in response injury

Answer 23

in response to injury, local inflammatory cells (neutrophils, granulocytes and macrophages) secrete a number of sytokines into the bloodstream, most notable of which are the interlukins

IL-1, IL-6, IL-8 and TNFa

Question 24

positive acute phase proteins

Answer 24

some act to destroy or inhibit the growth of microbes (CRP, moonose binidn protein, complement factors, ferritin, ceruloplasmin, serum amyloid A and haptoglobin)

other give negative feedback on the inflammatory response (serpins, a 2-macroglobin and coagulation factors)

Question 25

coagulation factors

Answer 25

negative acute phase protein

affect coagulation stimulating it

pro-coagulant effect may limit infection by trapping pathogens in local blood clots

also, some products of the coagulation system can contribute to the innate immune system by their abilibty to increase vascular permeability and act as chemotactic agents for phagocytic cells

Question 26

Changes in C-reactive proteins

Answer 26

conditions that commoly lead to marked changes in CRP include infection, trauma, surgery, burns, inflammatory conditions, and advanced cancer.

moderate changes occur after strenuous exercise, heatstroke, and childbirth

small changes in CRP occur after psychological stress and in several psychiatric illnesses

CRP is a test of value. Marked rises in CRP reflect the presence and intensity of inflammation. An elevation in CRP, however, is not a tell tale sign pointing to just one disease

Question 27

Pro-inflammatory cytokines

Answer 27

regulate inflammatory reactions either directly or by their ability to induce the synthesis of cellular adhesion moleucles or othe cytokines in certain cell types.

the major pro-inflammatory cytokines that are responsible for early responses are IL-1 a/b IL-6 and TNFa

Question 28

activation of IL1-b by various caspases

Answer 28

proceeds in a large multiprotein complex that has been termed inflammasome