Microbiology (chapter 15)

What are the basic functions of helper T cells? (select all that apply) Activation of macrophages Direct lysis of extracellular bacteria Activation of B cells Coordination of activities of B cells, macrophages, and other T cells Induction of apoptosis in infected self cells

Activation of macrophages Activation of B cells Coordination of activities of B cells, macrophages, and other T cells

______ gather antigens using pinocytosis, phagocytosis, and sending tentacle-like extensions between epithelial cells to mucosal surfaces. T cells Neutrophils Dendritic cells B cells

Dendritic cells

The function of the two arms of the Y-shaped antibody molecule is to ______. help activate the classical complement cascade bind to Fab regions be bound by our own system's cells bind to epitopes, or antigenic determinants

bind to epitopes, or antigenic determinants

Which type of antigen is most common? T-dependent T-independent

T-dependent

If an immune system lost the ability to make helper T cells, the B cells could still be activated by ______. (select all that apply) T-dependent antigens T-independent antigens proteins polysaccharides

T-independent antigens polysaccharides

What is it about the traits of a T-independent antigen that can activate a B cell without help from a T cell? The low number of BCRs on the surface are easily triggered by few repeating epitopes binding them all up, saturating the B cell's activation signals. The high number of repeating identical epitopes can cross-link many BCRs at once, providing a strong activation signal without T cells. These are more easily brought into the cell than T-dependent protein antigens, allowing for easier processing to take place during activation. The large size of these molecules leads to easier cross-linking of BCRs and activation without T cell help.

The high number of repeating identical epitopes can cross-link many BCRs at once, providing a strong activation signal without T cells.

Memory B cell production occurs ______. after class switching has taken place before class switching has taken place before affinity maturation has taken place only after all antigen has been eliminated

after class switching has taken place

An antigen is a molecule capable of interacting with ______. (select all that apply) an antibody receptor on a macrophage an antibody molecule a complement receptor on a macrophage a B-cell receptor

an antibody molecule a B-cell receptor

The term "antigen" is derived from the descriptive expression "_______________ generator."

antibody

The receptor on the surface of B cells is most similar to a(n) ______. CD8 marker antibody molecule MHC Class II molecule CD4 marker MHC Class I molecule

antibody molecule

The main function of the lymphatic system is to allow _________ to interact with and activate lymphocytes.

antigens

B cells with anti-self B-cell receptors (BCRs) undergoing negative selection in the bone marrow are induced to undergo ___________

apoptosis

Cytotoxic T cells (Tc cells) induce ______ in infected self cells and cancerous cells. antigen presentation cell division apoptosis mitosis

apoptosis

The lymphatic system's primary role is to _______. provide a safe environment in which B cells and T cells can mature bring antigens into contact with lymphocytes, allowing activation, proliferation, and differentiation of specific B and T cells into effector cells bring antigens into contact with complement proteins for effective binding, followed by elimination

bring antigens into contact with lymphocytes, allowing activation, proliferation, and differentiation of specific B and T cells into effector cells

The cells that have the general role of interacting with target cells and then inducing changes in them are ______. (select all that apply) cytotoxic T cells plasma B cells helper T cells

cytotoxic T cells helper T cells

____________ cells, a type of antigen-presenting cell, are responsible for initial activation of naive T lymphocytes in lymph nodes during a cell-mediated immune response.

dendritic

A particular type of cell from the innate immune responses is critical for initial T cell activation in lymph nodes. This cell is the ______. epithelial cell macrophage dendritic cell neutrophil B cell

dendritic cell

Most antigens are T-____________ , meaning that T-helper cells are required for confirmation.

dependent

The basic functions of effector cytotoxic cells (TC cells) include ______. (select all that apply) destruction of cancerous self cells induction of apoptosis in infected self cells assistance of B cell activation direct attack of extracellular bacteria assistance in activating macrophages

destruction of cancerous self cells induction of apoptosis in infected self cells

Helper T cells orchestrate the immune response by ______. (select all that apply) producing antibodies directing the activities of B cells, macrophages, and T cells activating B cells and macrophages directing cancerous or infected cells to undergo apoptosis

directing the activities of B cells, macrophages, and T cells activating B cells and macrophages

Unlike B and T cells, NK cells ______. are not leukocyte do not have antigen specific receptors are not innate lymphoid cells (ILCs) are not lymphocytes

do not have antigen specific receptors

The human genome ______. has more than 100 million genes for antibody molecules, with each gene encoding one specificity of antibody molecule does not have the coding capacity to have one gene per specific antibody molecule

does not have the coding capacity to have one gene per specific antibody molecule

Clonal selection is a critical theme in the adaptive immune response. The two main features are that ______. lymphocytes produce their antigen receptors when they are in the presence of antigen each lymphocyte recognizes and responds to only a single epitope a population of lymphocytes able to recognize a functionally limitless variety of antigens is generated each lymphocyte produces an enormous diversity of different antigen receptors

each lymphocyte recognizes and responds to only a single epitope a population of lymphocytes able to recognize a functionally limitless variety of antigens is generated

Natural killer cells belong to the group of lymphocytes called ______. T lymphocytes innate lymphoid cells B lymphocytes

innate lymphoid cells

The primary cellular participants in the adaptive immune responses are macrophages lymphocytes complement proteins neutrophils antibodies

lymphocytes

______________ , which include B cells and T cells, are the primary cell type involved in the adaptive immune responses.

lymphocytes

The clonal selection theory states that there are ______. many lymphocytes produced, and each is capable of reacting with multiple different epitopes few lymphocytes produced, and each is only capable of reacting with one specific epitope many lymphocytes produced, but each has only one specific epitope it will react with few lymphocytes produced, but each is capable of reacting with multiple different epitopes

many lymphocytes produced, but each has only one specific epitope it will react with

______________ B cells are long-lived and allow for a much faster response if the same antigen is encountered at a later date.

memory

When a B cell receptor (BCR) binds antigen, and the naive B cell is activated by confirmation from a helper T cell, the B cell then begins to ______. differentiate into plasma cells multiply form memory B cells produce antibodies

multiply

An antigen interacting with a T-cell receptor ______. must be broken down into peptide fragments and presented on a B-cell receptor must be completely intact and in its original form must be broken down into peptide fragments and presented on an MHC molecule leads to the T cell pulling in the antigen and TCR complex in an endosome for degradation and presentation

must be broken down into peptide fragments and presented on an MHC molecule

Positive selection mechanisms in lymphocytes occurs ______. (select all that apply) only in T cells due to binding of a BCR to MHC molecules during development in the bone marrow due to binding of a TCR to MHC molecules during development and screening in the bone marrow in both B and T cells due to binding of a TCR to MHC molecules during development and screening in the thymus

only in T cells due to binding of a TCR to MHC molecules during development and screening in the thymus

A T-cell receptor (TCR) is ______. (select all that apply) only recognizes antigen that is presented by another cell is similar (but not identical) in function to a B cell receptor a terminal cassette repeat structure is found on the surface of all lymphocytes is found on the surface of T cells

only recognizes antigen that is presented by another cell is similar (but not identical) in function to a B cell receptor is found on the surface of T cells

All of the following are true of antigen processing and presentation in B cells EXCEPT ______. antigens are broken down into peptide fragments antigen and BCR complexes are brought into the B cell peptide fragments are loaded into B cell receptor molecules for presentation to helper T cells peptide fragments are loaded into MHC Class II molecules for presentation to helper T cells

peptide fragments are loaded into B cell receptor molecules for presentation to helper T cells

Dendritic cells gather material by ______. (select all that apply) pinocytosis extending tentacle-like extensions into tissue cells extending tentacle-like extensions between epithelial cells to mucosal surfaces phagocytosis

pinocytosis extending tentacle-like extensions between epithelial cells to mucosal surfaces phagocytosis

The process that B cells use to generate diversity in the B-cell receptors is ______. very different from the process that T cells use to generate diversity in T-cell receptors similar to the process that T cells use to generate diversity in T-cell receptors

similar to the process that T cells use to generate diversity in T-cell receptors

T cells mature in the __________ and B cells mature in the bone _________

thymus, marrow

The main outcome of B cell activation is ______. triggering the cell to undergo apoptosis causing the cell to differentiate into a different form with enhanced killing power directly stimulating large-scale antibody production from the B cell triggering the cell to multiply

triggering the cell to multiply

Humoral immunity is generally used to eliminate extracellular antigens such as ______. (select all that apply) viruses in tissue fluids tuberculosis pathogens ingested by macrophages toxins viruses replicating in cells bacteria

viruses in tissue fluids toxins bacteria

Cell-mediated immunity (CMI) deals with intracellular pathogens and antigens such as ______. bacteria in the bloodstream viruses replicating in a cell toxin molecules viruses in tissue fluids

viruses replicating in a cell