GENERAL ANATOMY
IMMUNE SYSTEM
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
when an antigen is displayed by a dendritic cell.
|
|
|
when a cytotoxic T cell releases cytokines.
|
|
|
when natural killer (NK) cells come in contact with a tumor cell.
|
|
|
) in the bone marrow during the self-tolerance test.
|
Detailed explanation-1: -In a primary antibody response, naïve helper T cells are activated in a peripheral lymphoid organ by binding to a foreign peptide bound to a class II MHC protein on the surface of a dendritic cell.
Detailed explanation-2: -Mature DCs are characterized by the production of cytokines, such as IL-12, and by the expression of homing receptors, such as CCR7, which directs the migration of DCs into the T-cell regions of secondary lymphoid organs. Together these changes enable DCs to effectively activate naïve T cells.
Detailed explanation-3: -After binding to the antigen and MHC class II molecule presented by the dendritic cell, the naïve helper T cell becomes activated and proliferates. Instead of gaining the ability to kill infected cells, helper T cells acquire the ability to activate cells that bear MHC class II molecules.
Detailed explanation-4: -MHC class II molecules sense when there’s an infection or foreign substance in your body. The CD4 receptor and MHC class II molecules activate the helper T-cells. The helper T-cells release molecules called cytokines. Cytokines send messages to other immune cells to start an immune response.