Lymphocytes V Flashcards Preview

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Flashcards in Lymphocytes V Deck (14)
1

How do thymus dependent antigens contribute to class switching and immunologic memory?

Through direct contact of B cells with Th cells (CD40-CD-40 ligand interaction) (p.198)

2

Where do CD4+ T cells become helper T cells?

In the lymph node (p.195)

3

Where do helper T cells become activated by IL-12 to form Th1 cells?

In the lymph node (p.195)

4

Where do helper T cells become activated by IL-4 to form Th2 cells?

In the lymph node (p.195)

5

What cytokine induces Th1 cell production in the lymph node?

IL-12 (p.195)

6

What cytokine induces Th2 cell production in the lymph node?

IL-4 (p.195)

7

Where does T cell positive selection occur?

In the thymic cortex (p.195)

8

Where does T cell negative selection occur?

In the thymic medulla (p.195)

9

What is positive selection?

Selection of T cells expressing TCRs that are capable of binding surface self MHC molecules will survive (p.195)

10

What is negative selection?

Apoptosis of T cells that express TCRs with high affiinity for self antigens (p.195)

11

Name the three types of antigen presenting cells.

Dendritic cells, macrophages, B cells (p.196)

12

What is the only type of APC that can activate a naiive T cell?

Dendritic cells (p.196)

13

What is required for T cell activation, for B cell activation, and for class switching?

Two signals (p.196)

14

What are the four steps in naiive T cell activation?

1.) foreign body is phagocytosed by a dendritic cell; 2.) foreign antigen is presented on MHC II and recognized by TCR on Th (helper) cells. Antigen is presented on MHC I to Tc cells. This is signal 1; 3.) A costimulatory signal is given via the interaction of B7 and CD28 (signal 2); 4.) Th cell activates and produces cytokines. Tc cell activates and is able to recognize and kill a virus infected cell (p.196)