Lsn 13 HW 20.8-20.14

Which statement is most accurate regarding immunological escape? Daughter cells that display tumor-specific antigens will not be attacked by NK cells. If a primary tumor has a surrounding capsule, the cells within absolutely cannot provoke a massive response by NK cells. Once immunological escape has occurred, cancer cells remain stationary. Cancer cells often mutate and can sometimes avoid detection by NK cells.

Cancer cells often mutate and can sometimes avoid detection by NK cells.

Which characteristic of MHC proteins is most accurate? Class II MHC proteins appear in the plasma membrane only when the cell is processing antigens. Antigen presentation by Class II MHC proteins is triggered by viral or bacterial infection of a body cell. Class II MHC proteins are always present in the membranes of all nucleated cells. Antigenic fragments are displayed by Class I MHC proteins on the plasma membrane.

Class II MHC proteins appear in the plasma membrane only when the cell is processing antigens.

The movement of phagocytes through the capillary wall is called phagocytosis. involution. diapedesis. apoptosis. chemotaxis.

diapedesis.

Before specific defenses are activated, most antigens must bind to the DNA of the lymphocyte. be processed by a phagocyte. depolarize the lymphocyte. infect cells. either infect cells or be processed by a phagocyte.

either infect cells or be processed by a phagocyte.

Histamine increases blood flow and vascular permeability. This would account for all of the following changes that occur during inflammation except movement of defense proteins and cells into the interstitial space. swelling of the inflamed tissue. chemotaxis of phagocytes. redness of the inflamed tissue. heat of the inflamed tissue.

chemotaxis of phagocytes.

The attraction or repulsion of certain cells to chemicals in their environment is called diapedesis. apoptosis. phagocytosis. chemotaxis. immune surveillance.

chemotaxis.

The effects of activating the complement system include all of the following except histamine release. destruction of target cell plasma membranes. enhanced phagocytosis. inhibition of the immune response. stimulation of inflammation.

inhibition of the immune response.

Nonspecific defenses include phagocytic cells. interferons. physical barriers. inflammation. All of the answers are correct.

All

The role of antigen-presenting cells in immunity is to display antigen fragments. process antigens. activate T cells. All of the answers are correct. None of the answers is correct.

All

The cells responsible for antibody-mediated immunity are the ________ cells. suppressor T helper T B cytotoxic T NK

B

The body's nonspecific defenses include all of the following except interferon. inflammation. B and T cells. complement. the skin.

B and T cells

The cells that perform immunological surveillance are the ________ cells. suppressor T B helper T plasma NK

NK

The cells directly responsible for cell-mediated immunity are the ________ cells. plasma NK interferon T B

T

What is perforin? a protein produced by NK cells a toxin expressed by some pathogens that is capable of damaging healthy cells a destructive enzyme secreted by sebaceous glands a type of interferon a type of antibody synthesized by B cells

a protein produced by NK cells

The classic pathway of complement activation begins when the complement protein binds to an antibody attached to an antigen. a cell surface antigen. the cell wall of bacteria. the plasma membrane of bacteria. a plasma protein.

an antibody attached to an antigen.

An inflammatory response is triggered when mast cells release histamine and heparin. neutrophils phagocytize bacteria. blood flow to an area increases. T cells release interferon. red blood cells release pyrogens.

mast cells release histamine and heparin.

Which of the following are abundant, mobile, and quick to phagocytize cellular debris or invading bacteria? neutrophils fixed macrophages free macrophages eosinophils

neutrophils

The first line of cellular defense against pathogens are the phagocytes. T cells. plasma cells. B cells. NK cells.

phagocytes.

Defense of the body against a particular pathogen is provided by nonspecific immunity. fever. skin defenses. specific immunity. immunological surveillance.

specific immunity.

Interferons are released by some macrophages and lymphocytes, but also by cells carrying what pathogen? viruses bacteria parasites spirochetes prions

viruses