Chapter 17 adaptive immunity

What is the correct sequence of events for activation of a B cell by a T-dependent antigen?

(1) Immunoglobulin receptors on the B cell recognize and bind the antigen. (2) An antigen fragment in complex with MHC class 2 is displayed on the B cell's surface. (3) The MHC-antigen complex binds a receptor on a TH cell. (4) The TH cell secretes cytokines that activate the B cell.

How do phagocytes communicate to other cells what they have captured?

They present antigens from engulfed foreign cells

Tom has a genetic disorder in which he does not synthesize class I MHC proteins or functional NK cells. Which of the following statements would be true for Tom?

Tom would not be able to destroy virally-infected cells.

Phagocytosis is a process for engulfing large particles (>1μm). Which feature of antibodies will help to make particles larger, therefore enhancing phagocytosis?

agglutination

Antigen processing and presentation

is a way for a cell to give information about its activities.

An individual may be exposed to a pathogen and become infected without actually getting sick. This is known as a subclinical infection. Even in subclinical infections, the individual's adaptive immune system can generate memory for the pathogen. What type of adaptive immunity is this?

naturally acquired active immunity

The flu virus mutates fairly frequently. Its adhesive proteins change such that we have different "strains" of influenza each year. When a particular flu virus mutates such that its adhesive proteins change, which function of antibodies is disrupted?

neutralization

__________________ stimulated with ___________ differentiate into __________, which secrete antibodies into the bloodstream.

B-cells, antigen, plasma cells

Which of the following statements concerning cellular immunity is FALSE?

Cellular immunity involves cells that recognize antigens and make specific antibodies against them.

Which of the following would you likely see on the surface of a human dendritic cell following phagocytosis of a bacterium?

Class I MHC with dendritic cell antigens and Class II MHC with engulfed bacteria

What would a virally infected skin epithelial cell have on its cell surface?

Class I MHC with skin cell antigens

Which type of cell directly attacks infected cells?

Cytotoxic T-cells

HIV directly infects T-cells. Why is this problematic for cell-mediated immunity?

Cytotoxic T-cells begin to attack the virally infected T-cells, reducing the number of T-cells in the body.

Which of the following are likely to be found on an MHC-I protein?

Damaged mitochondrial fragment

Cytokines are produced by which of the following cells?

Helper T-cells

How do helper T-cells and cytotoxic T-cells work together?

Helper T-cells produce cytokines to activate other cells of the immune system.

Antibodies are a part of which type of immunity?

Humoral

Which part of the adaptive immune response involves B cells?

Humoral

If a patient has been exposed to an antigen for the first time, which class of immunoglobulin appears first?

IgM

Why would a body cell that is not a phagocyte need to present antigens?

Non-phagocytic body cells can become infected with a virus.

Which cytokines are believed to contribute to autoimmune disease, such as rheumatoid arthritis?

tumor necrosis factor (TNF)

Which structure do antigen presenting cells utilize to directly help them present bacterial antigens?

Phagolysosome

Which type of T cell is involved in activating macrophages and stimulating development of cytotoxic T cells?

TH1 cells

Which of the following statements concerning immunological memory is true?

The memory response is due to production of long-lived cells that can respond very rapidly upon second exposure.

Consider a helminthic infection in which an individual is colonized by a parasitic worm. The worm is too big to be engulfed by a phagocytic cell. How does the immune system respond?

The worm gets coated with antibodies, which activate other cells in the immune system to secrete chemicals that kill it.

Which of the following statements concerning antigen-presenting cells is true?

They are involved in activating T cells.