Mastering A&P Ch 21

Which of the following is NOT a step used by cytotoxic T cells to kill infected host cells?

Recognition of infected host cell using its CD4 glycoprotein The cytotoxic T cell uses its CD8 glycoprotein to bind to the MHC-I of an infected host cell.

Which of the following types of cells display protein fragments produced by the cancer within them?

all nucleated cells Yes, nucleated body cells bring pieces of endogenous proteins to the surface to display on the MHC protein.

What is the name of the unique area (specific region) that a lymphocyte recognizes and binds to?

an antigenic determinant also called an epitope, the antigenic determinant is the specific part of an antigen that the antibody or lymphocyte antigenic determinant receptor binds to.

Which of the following activate CD8 cells?

antigen fragments on class I MHC proteins T cells bearing CD8 receptors are activated by cells presenting endogenous antigens on class I MHC proteins.

Class II MHC proteins are found on which of the following cell types?

antigen-presenting cells Yes, class II MHC proteins are found only on antigen-presenting cells.

If a virus attacks a cell, which type of immunity would be activated?

cell-mediated immunity (cellular immunity) cell-mediated immunity involves an intracellular pathogen such as a virus.

Which class of MHC proteins presents exogenous antigens?

class II MHC proteins class II MHC proteins present antigens that originated from outside the cell (phagocytized extracellular pathogens).

What type of T cell can directly attack and kill other cells, such as virus-infected cells?

cytotoxic T (TC) cells can distinguish between self cells and cells from the transplanted tissue. If a cytotoxic T cell recognizes its own antigen on a virus-infected cell, the T cell will destroy it.

Activated CD8 cells become __________.

cytotoxic T cells

What type of immunity can be transferred by bodily fluids from one person to another, thus conferring immunity to the recipient?

humoral immunity humoral immunity involves antibodies that can be transferred from one person to another.

Tears and mucus membranes would be a part of which defense system?

innate external defenses innate external defenses (surface barriers) are the first line of defense and include tears, mucus membranes, and the skin.

Phagocytotic cells such as macrophages identify a variety of enemies by recognizing markers unique to pathogens. They would be classified as which type of defense system?

innate internal defenses the macrophage recognizes many molecules found on pathogens that are not present on normal body cells.

Which cells secrete histamines that trigger inflammatory pathways?

mast cells Mast cells have granules that contain histamines.

Which of the following is an effect of complement activation?

opsonization Complement proteins stimulate inflammation, serve as opsonins to aid in the phagocytosis of targeted antigens, and facilitate cytolysis.

Which of these mechanisms do cytotoxic T (TC) cells use to destroy a target--that is, deliver a lethal hit?

perforation of the membrane Perforin molecules released by the cytotoxic T cause the formation of pores in the target membrane, leading to the cell's death. T cells can also cause apoptosis (cell lysis).

T cells achieve self-tolerance in the __________.

thymus T cells learn and are screened for self-tolerance in the thymus.

Steps of phagocytosis

1) Dendritic cell engulfs Rhinovirus 2)Endosome fuses with lysozome 3)Digestion of the Rhinovirus 4)Epitopes are attached to MHC-II 5)MHC-II plus the attached epitope move to the outside of the dendritic cell

Steps involved cellular immunity:

1) The Tc interacts with epitope presented by MHC-I on the dendritic cell 2)The helper T cell activates the Tc cell 3)The Tc recognizes the infected host cell 4)The Tc secretes perforin and granzyme, causing apoptosis

Which of the following is NOT a step that ultimately leads to antibody production?

Activation of cytotoxic T cells by helper T cells The activation of cytotoxic T cells leads down the path of cell-mediated immunity.

Which of the following statements is true?

Adaptive defenses include both humoral and cellular immunity. This answer is correct. Adaptive defenses are operating optimally when both humoral and cellular immunity are working together in response to a pathogen.

What is meant by the clonal expansion of a B cell?

An activated B cell divides into cells that give rise to memory B cells and plasma cells The activated B cell divides until there are many clones. Some differentiate into memory cells, other become plasma cells that produce and secrete antibodies.

Which of the following are antigen-presenting cells (APC)?

B cells B cells can present antigens to T helper cells.

Which pair of molecules do NOT directly interact with one another?

BCR and TCR Both of these molecules interact with epitopes. BCRs interact with epitopes on the whole pathogen. TRCs interact with processed epitopes when presented on MHC-II.

Class I MHC proteins are recognized by which of the following cell types (that are destined to become T cells)?

CD8 class I MHC proteins are recognized by CD8 cells.

Which major class of lymphocytes become cytotoxic T cells?

CD8 cells CD8 cells become cytotoxic T cells.

A person who has AIDS contracts rare and often life-threatening infections because their helper T cell count is so low. Which of the following components of the immune response still respond to antigen despite the low helper T cell count?

Clonal selection of B cells B cells can still bind to antigen, which is the process of clonal selection. However, without a helper T cell, clonal expansion and antibody production will not occur.

Which type of T cell will recognize antigens associated with an organ transplant?

Cytotoxic T (TC) Cytotoxic T (TC) cells can distinguish between self cells and those from the transplanted tissue. If a cytotoxic T cell recognizes its own antigen on a transplanted cell, the T cell will destroy it, leading to organ rejection

Cancer cells would be attacked by which of the following cells?

Cytotoxic T cells cytotoxic T cells attack cancer cells, since they are part of cell-mediated immunity.

What is the role of helper T cells in the adaptive immune response?

Helper T cells activate B cells and cytotoxic T lymphocytes to kill infected host cells. Helper T cells activate B cells that are displaying antigen, causing clonal expansion. Helper T cells also activate cytotoxic T cells, which will search for and destroy infected host cells.

The student who caught the cold caused by this specific Rhinovirus was exposed to the exact same Rhinovirus 18 months later. What component of the immune system will protect her from getting the same cold again?

Memory B cells Memory cells to that specific virus are stored in the lymph nodes for many years. When the student comes into contact with this specific Rhinovirus, these memory cells quickly divide and differentiate into antibody-producing plasma cells. The antibodies will prevent the virus from reaching an infectious titer (number that causes infection).

Which of the following cells engulf antigens and present fragments of them on their own surfaces for recognition?

dendritic cells Dendritic cells are antigen-presenting cells that engulf antigens and then present fragments of them to their own surfaces, where T cells can recognize them.

Which of the following are NOT appropriately matched?

helper T cells: destroy infected cells Helper T cells are lymphocytes that manage or orchestrate an immune response, but they do not directly kill cells.

What cells make antibodies?

plasma B cells plasma B cells make antibodies in response to specific antigens.