Flashcards in Cells and Tissues of the Adaptive Immune System Deck (48):
what are the primary lymphoid organs?
thymus and bone marrow
what are the secondary lymphoid organs?
spleen, lymph nodes, and mucosa-associated lymphoid tissue
where do all blood cells develop from ?
common pluripotent stem cells
where do T cells proliferate, differentiate, and complete their maturation?
where do B cells proliferate, differentiate, and complete their maturation?
what kind of receptors are localized on the surface of T and B cells?
Ag - specific receptors
explain the structure of Ag-specific receptors on T and B cells.
the structure varies from one cell to another but they are all identical on a single cell.
if naive lymphocytes do not recognize Ag, how long does it take them to die?
1 to 3 months
What another name for treg cells?
cytokines IL-1 IL-2 IL-6 and IL-7 play an important role in the development of which cell?
what do naive cells refer to?
B cells or T cells that have not yet been exposed to Ag
where are naive cells maintain ?
in the periphery without proliferating
what are the two different kinds of T cells developed? what do they express
T helper cells which express CD4 and provide help for B cell growth and differentiation
cytotoxic T lymphocytes (CTLs) express CD8 and recognize and kill virus-infected cells
where to functionally mature T cells migrate to ?
to secondary lymphoid tissues to mediate protection
at birth what color is bone marrow?
what color is bone marrow in adults?
half red and half yellow
where does differentiation into B cells occur before and after birth?
before in fetal liver
after birth in thymus
lymphocytes continuously circulate reaching various parts of the body except which few?
eye, brain, and testicles
in search of foreign Ags, lymphocytes enter the secondary lymphoid organs vis a specialized endothelium of post capillary venues called what?
high endothelium venules HEV
cells of HEV express high levels of ______ that serve as what?
"homing" receptors for lymphocytes
Lymphocytes transmigrate by what?
by diapedesis into the tissue in response to chemokine
Lymphocytes reenter the circulation via what?
via efferent lymph vessels that merge into the thoracic duct
lymphocytes may be activated by foreign Ags in these secondary lymphoid tissue, but if not, and they're still naive lymphocytes, they will return to the blood by what?
Explain the steps in activation of B cells.
naive B cells migrate into the secondary lymphoid tissue where they look for and respond to soluble foreign Ags
Ag activated b cell proliferate in germinal centers and mature into memory cells or into plasma cells
plasma cells is terminally differentiated b cells which produce and secrete large amount of Abs
in the spleen, Ag activated b cells primarily produce Abs against microbial in the blood
in the spleen, t cell and b cell zones makes up the _____ pulp.
Explain the steps in activation of T cells.
in search of foreign Ag, naive T cells migrate into secondary lymphoid organs such as lymph nodes
t cells which were activated by Ags differentiate into effector or memory t cells
some effector and memory t cells migrate back into the peripheral sites of infection
some activated and differentiated T cells remain in the LNs and help AG activated B cells to become "an Ab factory"
the naive cells enter the lymph node through what?
an artery leaving the circulation by moving across the HEV
B and t cells migrate to different zones of the lymph node directed by what?
by chemokines that are produced in these areas by stroll cells
Das pick up Ags from the sites of Ag entry and enter through what?
through afferent lymphatic vessels
where do Das migrate in the lymph node?
to the T cell rich areas of the node
what type of follicles can be found in the lymph nodes?
primary and secondary
in the absence of Ag stimulation, explain the follicles in the lymph nodes.
follicles are primary follicles, composed of naive b cells or recirculating memory B cells
with Ag stimulation, b cells proliferate and differentiate converting the primary follicle into what?
into a secondary follicle or germinal center
Professional APCs are:
Do T cells of B cells need APC?
What are APCs?
they are cells that capture, process, and display Ags to T lymphocytes and provide signals that stimulate the proliferation and differentiation of the lymphocytes
Which cells provide a link between innate and adaptive immunity?
DCs and tissue Macrophages
Das are part of the _____ lineage.
Das can be broadly divided to what?
classical Das, myeloid (mDCs) and plasmacytoid DCs (pDCs)
what are DCs derived from?
classical Das, pDC and langerhan's cells (LCs) in epidermis of the skin, develop directly from what?
from stem cells
what do DCs use to acquire Ags?
use phagocytosis, receptor-mediated endocytosis, and pinocytosis
activated DCS also secrete what?
where do classical Das reside?
in skin, mucosa, and organ parenchyma
upon activation by microbes, classical Das migrate to lymph nodes where they display what to T lymphocytes?
display microbial protein Ags to T lymphocytes
plasmacytoid DCs are early cellular responders to what?
to viral infection
what do plasmacytoid DCs recognize and produce?
recognize nucleic acids of intracellular viruses
produce soluble interferons a.k.a. IFN-alpha/beta