CHAPTER 2: Nature of Antigens and the Major Histocompatibility Complex

All of the following are characteristics of an effective immunogen except

Internal complexity

Large molecular weight

The presence of numerous epitopes

Found on host cells

Which of the following best describes a hapten

Cannot react with antibody

Antigenic only when coupled to a carrier

Has multiple determinant sites

A large chemically complex molecule

Which would be the most effective immunogen

Protein with a molecular weight of 200,000

Nylon polymer with a molecular weight of 250,000

Polysaccharide with a molecular weight of 220,000

Protein with a molecular weight of 175,000

Which of the following individuals would likely respond most strongly to a bacterial infection?

An adult who is 75 years of age

A malnourished 40-year-old

A weightlifter who is 35 years old

A newborn baby

Which best describes an epitope?

A peptide that must be at least 10,000 MW

An area of an immunogen recognized only by T cells

A segment of sequential amino acids only

D. A key portion of the immunogen

Adjuvants act by which of the following methods?

Protects antigen from being degraded

Facilitates rapid escape from the tissues

Limits the area of the immune response

Decreases number of APCs

A heterophile antigen is one that

Is a self-antigen.

Exists in unrelated plants or animals.

Has been used previously to stimulate antibody response.

Is from the same species but is different from the host.

Which of the following is true of class II MHC (HLA) antigens?

They are found on B cells and macrophages.

They are found on all nucleated cells.

They all originate at one locus.

They are coded for on chromosome 9.

Class II MHC molecules are recognized by which of the following?

CD4+ T cells

CD8+ T cells

Natural killer cells

Neutrophils

Which of the following best describes the role of TAP?

They bind to class II molecules to help block the antigen-binding site.

They bind to class I proteins in proteasomes.

They transport peptides into the lumen of the endoplasmic reticulum.

They help cleave peptides for transport to endosomes.

What is the purpose of the invariant chain in antigen processing associated with class II MHC molecules?

Helps transport peptides to the binding site

Blocks binding of endogenous peptides

Binds to CD8+ T cells

Cleaves peptides into the proper size for binding

An individual is recovering from a bacterial infection and tests positive for antibodies to a protein normally found in the cytoplasm of this bacterium. Which of the following statements is true of this situation?

Class I molecules have presented bacterial antigen to CD8+ T cells.

Class I molecules have presented bacterial antigen to CD4+ T cells.

Class II molecules have presented bacterial antigen to CD4+ T cells.

B cells have recognized bacterial antigen without help from T cells.

In relation to a human, alloantigens would need to be considered in which of the following events?

Transplantation of a kidney from one individual to another

Vaccination with the polysaccharide coat of a bacterial cell

Oral administration of a live but heat-killed virus particle

Grafting skin from one area of the body to another

Which is characteristic of class I MHC molecules?

Consists of one α and one β chain

Binds peptides made within the cell

Able to bind whole proteins

Coded for by DR, DP, and DQ genes

Class I MHC antigens E and G serve which function?

Enhance the response by macrophages

Transport antigen for recognition by CD4+ T cells

Bind to A, B, and C antigens to protect the binding site

Protect fetal tissue from destruction by NK cells

Which best explains the difference between immunogens and antigens?

Only antigens are large enough to be recognized by T cells.

Only immunogens can react with antibody.

Only immunogens can trigger an immune response.

Only antigens are recognized as foreign.

When a child inherits one set of six HLA genes together from one parent, this is called a(n)

Genotype

Haplotype

Phenotype

Allotype

CHAPTER 2: Nature of Antigens and the Major Histocompatibility Complex

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