Chapter 12: Coevolution Of Innate And Adaptive Immunity

Question 1

Bridging innate and adaptive immunity

Answer 1

• evolutionary models for innate and adaptive immunity emergence
• innate immunity start first upon infection. After about a week adaptive immunity kicks in

Question 2

Gamma:Delta T cells contribute to the innate immune response

Answer 2

• these cells do not need to recognized antigen with MHC complexes
• most gamma:delta T cells recognize phosphoantigens, which contain a pyrophosphate group derived from pathogenic microbes
• gamma:delta receptor are similar to TLRs in that they recognize groups of common antigen
• can produce TNF-alpha, IFN-gamma, granulysin to take care of business

Question 3

Gamma:Delta T cells recognize stress-induced MIC proteins via their…

Answer 3

• NKG2D receptor

- T cells with Vgamma:VDelta1 and NKG2D receptors are resident in the intestinal mucosa, where they respond to infection

Question 4

Gamma:Delta T cells are not governed by the same rules as alpha:beta T cells

Answer 4

—-

Question 5

Individual NK cells express many different combinations of receptors belonging to one or two receptor families.

Answer 5

• NK are lymphocytes that function in the innate immune response in the defense against viral infections
• many of the NK receptor cells are either from the immunoglobulin family superfamily or are like lectin-like-receptors that are recognized by mannose or similar carbohydrates

Question 6

The receptor ____________ (lectin like and activating) is expressed by all NK cells. Other receptors vary from NK cell to NK cell

Answer 6

• NKG2D

Question 7

Most receptors are either structurally similar to ____________ lectins, like ____________, or are made up of immunoglobulin-like domains.

Answer 7

• C-type

- NKG2D

Question 8

The strongest receptor that activates NK cells is an…

Answer 8

• FC receptor

- meaning that antibodies are potent activators of NK cells

Question 9

NK cells use receptors for MHC Class ____ molecules to identify infected cells

Answer 9

• Class 1
• NK cells can detect the presence of infection by using the combination of an inhibitory receptor specific for MHC class 1 peptides and an activating receptor (NKG2D) specific for MIC

Question 10

Healthy cells have normal level of MHC class 1 molecules and do not express the MIC stress protein that binds NKG2D

Answer 10

• on contacting a healthy epithelial cell the inhibitory signal to the NK cell, which then leaves the epithelial cell untouched.

Question 11

If an epithelial cell infected with a virus the expression of MIC is induced, and expression of MHC class 1 molecules is lost.

Answer 11

• when the NK cell contacts the virus-infected cell, the binding of NKG2D to MICs on the infected cell’s surface delivers an activating signal to the NK cell, which responds by killing the virus-infected cell.

Question 12

NK cells have ___________ receptors with different specificities for MHC class 1 molecules

Answer 12

• inhibitory

Question 13

__________-cell immunoglobulin-like receptor (KIRs) bind to the same face of the MHC Class 1 molecule as the T-cell receptor

Answer 13

• Killer

Question 14

Inhibitory receptors for self MHC class 1 make NK cells ___________ to self and responsive to loss of MHC ________ ___

Answer 14

• Tolerant

- Class 1

Question 15

NKT cells are of innate immunity that express gamma:delta T-cell receptors and are similar to NK cells

Answer 15

• CD1d presents lipid antigens from a wide variety of pathogens NOT to conventional gamma:delta T cells, but to NKT cells that express the gamma:delta T cell receptors as well many NK receptors

Question 16

What is CD1?

Answer 16

• an MHC Class 1-like glycoprotein that are neither polymorphic nor encoded within the MHC
• they (CD1a, b, c) present lipid antigens to the normal gamma:delta T cells receptors T cells
• upon activation, there is a powerful effector T cells that secrete4 cytokines and kill infected cells
• CD1d only presents to NKT cells

Question 17

CD1d receptors only presents to…

Answer 17

• NKT-cells

Question 18

Like g:d T-cells, NKT cells can…

Answer 18

• respond rapidly to infection
• do not generate a memory response
• are restricted to receptor repertoire
• participate in innate immune response

Question 19

NKT cells help in the initiation of the inflammatory responses and the recruitment of ____________, _____________, and________________ to the site of infection.

Answer 19

• Neutrophils
• NK cells
• Monocytes

Question 20

NKT cells are innate lymphocytes that detect ________ ________ by using ______:______ T cell receptors.

Answer 20

• lipid antigen
• alpha
• beta