Week 15 Review

1. ______ with antigen fragments displayed on their surfaces are known as antigen-presenting cells (APCs). 2. When activated by antigen-presenting cells, helper T cells release what cytokine that activates B cells and cytotoxic T cells? 3. Cytotoxic T cells know that a cell is infected because 4. B cells differentiate into ______, which make antibodies. 5. The immune system responds more quickly to second exposure to an antigen because

-Macrophages-Interleukin-2 -that cell has antigens from the disease -causing microbe on its surface. -plasma cells -memory B cells are produced during the first response

The compounds secreted or delivered by the T cell shown in the figure lead to

-death of the infected cell.-alerting neighboring cells to the presence of virus.

1. The adaptive immune response 2. T cells 3. Antigens 4. After repeated exposure to foreign material, innate immunity

-involves memory of antigens from previous exposure-are responsible for cell-mediated immunity-are molecules that can be recognized by B or T cells-continues to react the same way

B cell differentiation is stimulated by

interleukins

Many different antibodies can be made against a single antigen.

True

Place the labels on the correct position on the diagram to demonstrate your understanding of antigen-antibody binding outcomes. Not all labels are used.

*left to right*Top: Neutralization, Opsonization, Complement system activationBottom: ADCC, Cross-linking, Immobilization

Place the statements about T-cell activation in the correct order.

1. Dendritic cells recognize and take up antigen. 2. Antigen fragments are presented with MHC molecules on the dendritic cell cytoplasmic membrane. 3. Naïve T cells recognize and bind the antigen-MHC complexes on dendritic cells also displaying co-stimulatory molecules. 4. Activated T cells proliferate and differentiate. Anergic T cells undergo apoptosis.

Arrange the following events in clonal selection in the correct order:1. Helper T cells are activated.2. Macrophages ingest antigen.3. B cells differentiate into plasma cells and memory cells.

2, 1, 3

If antigen X bound to B cell W as well as to B cell X, what would happen?

B cell X would be selected for clonal expansion.

If another antigen, antigen Y, was also present and bound to B cell Y, what would the outcome be?

B cell X would produce anti-X antibodies and B cell Y would produce anti-Y antibodies.

If antigen X is a "self" antigen and it binds to B cell X, what should the outcome be?

B cell X would undergo class switching and would begin to produce a different antibody.

Match the following fungi with their mechanisms of pathogenesis.

Candida albicans = The fungus causes disease in immunocompromised hosts, such as AIDS patients. It generally infects the mucous membranes, causing thrush (an infection of the throat and mouth) or vulvovaginitis. Aspergillus flavus: This fungus grows on grains and nuts and produces aflatoxin. Ingestion of this toxin can damage the liver and increases the risk of liver cancer. Fungal spores and other products can cause hypersensitivities in some people.

Which of the following are antigen-presenting cells?

Macrophages and B cells are both APCs.

Which of the following is a mechanism used by pathogens for avoiding antibodies?

Molecular mimicry

Consider the figure of a lichen. In this symbiotic relationship, the photosynthetic alga provides the fungus with organic nutrients. The fungus provides the alga with water and protection. Which of the normal microbiota relationships described below is most similar to this association?

Mutualism - intestinal bacteria providing host with vitamins E and K.

Which of the following is NOT a matching pair. Bone marrow - B-cell development Plasma cells - antibodies Skin - first line of defense cell-mediated immunity - T cells B cells - MHC class II molecules Dendritic cells - T-cell activation Epitope - Antigenic determinant Payer's patches - skin

Peyer's patches - skin

The receptors found on the T cell in the figure are

T-cell receptors and CD8 proteins

Please place the steps in the correct order to assess your knowledge of Koch's postulates. Not all steps are used.

The microorganism must be present in every case of the disease but not in healthy hosts.The microorganism must be grown in pure culture from diseased hosts.The same disease must be produced when a pure culture of the microorganism is introduced into susceptible hosts.The same microorganism must be recovered from the experimentally infected hosts.

Helper T cells interact with target cells by recognizing

antigen-MHC protein complexes.

Antigens

are made up of many antigenic determinants (epitopes).

Helper T cells secrete ______ to stimulate the proliferation of B cells.

cytokines

Consider the figure of a virus infected cell. By directing the host cell to synthesize fake MHC class I molecules, the virus is

making sure its host is not destroyed by TC cells or NK cells.

B cell X is a _______ lymphocyte that is in the process of becoming _______, generating an effector B cell, also called a _______ cell.

naive; activated; plasma

Antibodies are produced by

plasma cells