Microbiology and Immunology 2500A/B Lecture 8: Immunology 8

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emeraldbeaver568

30 Jun 2016

School

Western University

Department

Microbiology and Immunology

Course

Microbiology and Immunology 2500A/B

Professor

Summers/ Mc Cormick/ Dikeakos

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Document Summary

Thymocytes in thymus coexpress cd8 and cd4 proteins on surface. In circulation becomes ctl or th cells depending on which cd protein is expressed on surface. Thymus larger in kids than adults since need to develop adaptive immunity so increased t cell production. Many copies of tcr"s on one t cell. In b cells, ig molecule can work while on cell surface or as independent antibody. In t cells, tcr always remains bound to cell surface not secreted as soluble molecule. Variable region on tcr specific to epitope on antigen on pathogen. Different combos of alpha and beta chains come together to form unique variable region on tcr. Every na ve t cell that arises has its own unique variable region on its tcr"s. Many t cells will mount immune response against pathogen. Specifically peptides thus 1 or 2 aa in protein chain. T cells cannot respond to non-protein antigens because hydrophilic.

Related Questions

Immunology worksheet help?

In people infected with human cytomegalovirus, class I MHC andb2-microglobulin are produced, but very little mature class I MHCis found at the cell surface. Inhibition of which of the followingmolecules by human cytomegalovirus may account for thisphenomenon?

A.	TAP
B.	Ii
C.	TCR
D.	CLIP
E.	RAG

Your chances of having the same MHC haplotype as your siblingare:

A.	1:2.
B.	1:4.
C.	1:16.
D.	1:8.
E.	1:1.

Which of the following is the BEST example of self-MHCrestriction of T cells?

A.	A T-cell clone is deleted when it binds too tightly to selfMHC.
B.	A T-cell clone responds more vigorously to a self-peptide thana foreign peptide.
C.	A T-cell clone recognizes foreign MHC.
D.	A T-cell clone only recognizes foreign peptides when presentedby self MHC.
E.	All of the above

MHC molecules:

A.	are conserved between individuals.
B.	bind repeating patterns found on pathogens.
C.	are recognized by T cells.
D.	are membrane-bound molecules found exclusively on T cells.
E.	are secreted by T cells and bind and neutralize antigen in theserum.

Tasmanian devils are a largely inbred population with littlediversity in the MHC. Which of the following would be a likelyoutcome of this?

A.	They would compensate for low diversity in the MHC with highdiversity in the TCR.
B.	They would compensate for low diversity in the MHC with highdiversity in the BCR.
C.	They would rely only on innate immune responses.
D.	They would be at higher risk of infection.
E.	All of the above

How many different MHC classical class I proteins does eachnucleated cell in a human heterozygous at the MHC locusexpress?

A.	Six
B.	Two
C.	Three
D.	One
E.	None. Only APC express class I.

MHC polymorphisms tend to cluster:

A.	in the peptide-binding groove.
B.	in the transmembrane domain.
C.	in the coreceptor contact residues.
D.	in the framework region.
E.	All of the above

A mutation that renders the MHC class II molecule DMnonfunctional would likely lead to:

A.	cells with no class II MHC.
B.	a deficiency in CD8⁺ T cells.
C.	cells with class II MHC only bound with CLIP.
D.	cells with class II MHC bound with a variety ofself-antigens.
E.	cells with no DO.

The human MHC locus is one of the most polymorphic regions ofthe genome. What does this mean?

A.	This region is regulated by many different mechanisms.
B.	Sequence variability is low in this region.
C.	There are many introns in this region.
D.	There are many different alleles of these genes.
E.	It has the most different genes.

10.

Which of the following is an example ofcross-presentation?

A.	An exogenous peptide being presented on MHC class II
B.	A B-cell antigen being presented to a T cell
C.	An endogenous peptide being presented on MHC class I
D.	An endogenous peptide being presented on MHC class II
E.	An exogenous peptide being presented on MHC class I

magentacamel430

1. Neutralizing antibodies are effective at preventing
infection or toxicity mediated by pathogens or their toxic products. In fact, nearly all vaccines currently in use function by eliciting neutralizing antibodies. The most important feature of a neutralizing antibody is:
A. Having a high degree of multi-valency, such as being a pentamer or hexamer of immunoglobulin monomers
B. Having high affinity for the antigen
C. Being present at a high concentration in the circulation
D. Being efficient at activating the complement cascade
E. Having a long half-life in the body

2. IgM antibodies are much more efficient than IgG at activating the complement cascade. However, under certain circumstances, IgG antibodies will activate the complement pathway. One example of a situation in which IgG binding to its antigen will
NOT trigger the complement cascade is when:
A. The IgG antibodies bind to a multivalent soluble antigen in solution, such as a polysaccharide structure shed from a bacterial pathogen.
B. The IgG antibodies bind to a viral capsid protein that is present in more than 100 copies on the viral particle surface.
C. The IgG antibodies bind to a bacterial surface by recognizing a repetitive polysaccharide component of the bacterial capsule.
D. The IgG antibodies are binding self-antigens such as chromatin released from dead cells.
E. The IgG antibodies are neutralizing a bacterial toxin protein by blocking the receptor-attachment site on the toxin.

3. Antibody-dependent cell-mediated cytotoxicity (ADCC) is an important effector mechanism in immunity to virus infections. This immune pathway has also been exploited for clinical applications. For instance, patients with
various disorders, including rheumatoid arthritis and some B cell lymphomas, are treated with an antibody directed at CD20, a surface receptor expressed on all B cells. This antibody leads to the depletion of B cells from the patients by the actions of:
A. Natural killer (NK) cells
B. Cytotoxic CD8 T cells
C. Cytotoxic CD4 T cells
D. Activated macrophages
E. The complement cascade membrane attack complex

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Microbiology and Immunology 2500A/B Lecture 8: Immunology 8

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