Exam 1: Cells and tissues of adaptive immune system Flashcards
(25 cards)
Where do all blood cells develop from?
common pluripotent stem cells.
What are referred to as the primary lymphoid organs?
thymus and bone marrow.
where are Ag-specific receptors localized?
on the surface of T and B cells.
If a naive lymphocyte doesn’t recognize Ag when do they usually die?
1 to 3 months.
Why are naive and memory lymphocytes both called resting lymphocytes?
b/c they are not actively dividing, nor are they performing effector functions.
- naive cells are in the G0 state of the cell cycle
- in response to stimuli they enter the G1 state of the cell cycle before going on to divide.
What does the survival of naive lymphocytes depend on?
signals generated by ag receptors (TCR or BCR) and cytokines.
How can a naive T lymphocyte (TCR) generate survival signal without triggering clonal expansion and differentiation into effector cells?
recognize various self Ags WEAKLY enough to generate survival signals.
What is the most important cytokine for survival of naive T cells
Interleukin IL-7
-promotes low-level cycling of naive T cells
What factor is required for naive B cell survival?
B -cell activating factor (BAFF), a cytokine belonging to the TNF family
what serves as soluble regulatory factors or “messengers” for the immune system
cytokines
Which cytokines play an important role in T cell development?
IL-1, IL-2, IL-6, and IL-12
What cells do immature T cells make contact with in the thymus
epithelial cells, DCs, and Macrophages.
After migration from the thymus most mature naive T cells are maintained where?
in the periphery without proliferating.
T Helper cells
express CD 4 and provide help for B cell growth and differentiation
Cytotoxic t lymphocytes (CTLs)
express CD8 and recognize and kill virus-infected cells.
Where do mature T cells migrate to mediate protection
secondary lymphoid tissues.
When do B-cells start to develop
from stem cells around the 14th week of gestation
Differentiation into B cells occurs with bone marrow in adults, where does it occur in the fetus?
fetal liver
Contact with stromal cells in the bone marrow and what cytokines are important for for the development of B cells?
IL-1, IL-6, and IL-7
NOTE WELL that IL-2 is not required for proliferation of B cells.
How are B cell receptors (BCRs = ABs) encoded?
in the bone marrow B cell precursors rearrange multiple, inherited, germline genes that encodes for recognition of Ag.
what happens to B cells with BCRs that react with self-Ags?
They are eliminated
What are the two types of B cells? What is the first antibody express on B cells?
B1 and B2
IgM followed by IgD
What is a plasma cell?
a terminally differentiated B cell which produce and secrete large amount of Abs.
CCR7
is a chemokine receptor expressed on naive T cells as well as mature dendritic cells. This receptor binds chemokines produced in the parafollicular zones of lymph nodes. T cell migration into lymph nodes is dependent on CCR7, and therefore a deficiency in CCR7 expression would result in reduced numbers of these cells in lymph nodes.
