Chapter 16 Mastering Questions

While the spleen is a secondary lymphoid organ, it is separate from MALT, which includes the appendix, Peyer's patches, and lymphoid tissues in the respiratory tract, vagina, urinary bladder, and mammary glands, because it filters blood instead of lymph.

strengthen the synapse. Th lymphocytes function in part to help stabilize an already-formed immunological synapse by binding to the APC using its own TCR.

the repertoire of B cells in children is not fully developed. Effective T-independent humoral immunity depends upon a fully developed and plentiful number of B cells. This is not the case in children, so they are more susceptible to diseases caused by pathogens with T-independent antigens.

Red blood cells do not serve as antigen-presenting cells, so they do not express MHC class II molecules.

self-stimulation of

is rapid. The speed of T-independent humoral immunity is similar to that of innate immunity, but it is relatively weak, does not last very long, and can be stimulated only by certain types of antigens.

The Fab region (fragment, antigen binding) is, by definition, the most variable region of the antibody molecule, since it is the part of the molecule that interacts with and binds to antigens.

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

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).

The Tc interacts with epitope, The helper T cell activates the Tc cell, The Tc recognizes the infected host cell, The Tc secretes perforin and granzyme, causing apoptosis

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.

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

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.

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

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.

Adaptive defenses include both humoral and cellular immunity

Interleukin-1. When immune cells sense pathogens, certain components of the pathogen stimulate the innate cells to produce cytokines. When Interleukin-1 is produced, it acts on the hypothalamus to "crank up the heat" and results in fever and increased inflammatory processes. The other cytokines listed have separate functions such as T-cell responses (Interleukin-2), B-cell responses (Interleukin -4), anti-inflammation (Interleukin -10), or cell differentiation (Interleukin -12).

artificially acquired active immunity

Bind it to a large protein.

naturally acquired passive immunity

formation of variable region gene combinations. Without RAG, recombination of BCR variable region genes cannot take place.

the gene for the mu Fc region is the first to be attached to the variable region gene. Since IgM is produced first during an infection, it fulfills an important role in limiting the infection.

secretory component. Perforin, granzyme, and CD95 all play a role in different types of cytotoxic T cell activity.

They are able to recognize MHC and do not recognize autoantigens. The majority of T cells that leave the thymus recognize MHC and foreign antigens, but they do not recognize autoantigens.

a phagolysosome. Fragments of endogenous antigens are complexed with MHC class I molecules in the endoplasmic reticulum. They are then packaged into vesicles by a Golgi body and transported to the cytoplasmic membrane, where they are exposed to the outside. Phagolysosomes are associated with the processing of exogenous antigens.

Staphylococcus aureus. Hepatitis B virus, Mycobacterium tuberculosis, and various types of cancers such as malignant melanoma would all be expected to stimulate a cell-mediated immune response. Staphylococcus aureus, like all extracellular bacterial pathogens, would be more likely to stimulate a humoral immune response.

IgA. Plasma cells begin by secreting IgM, but can class switch and begin making IgG. If they class switch a second time, they can make IgA or IgE.

innate defense

helper T cells.

T lymphocytes

Phagocytosis and the complement system

Cytotoxic T cells

Humoral

Humoral

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

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

They present antigens from engulfed foreign cells.