Immune I Flashcards
what are causes of immune over-reaction
- autoimmune problems 2. allergic reactions
causes of immune under-reaction
- cancer 2. infection
describe development of lympoid cells
hematopoetic stem cells differentiate to lympoid stem cells, which differentiate to B, T, andd NK cells, B cells terminally differentiate to plasma cells
describe development of myeloid cells
hematopoeitic stem cells differentiate to myeloid stem cells, differentiate into granulocytes, platelets, RBC and monocytes, granulocytes differentiate into basophils, eosinophils, and neutrophils
types of T cells
- helper T cells (CD4) 2. cytotoxic T cells (CD8) 3. regulatory T cells (CD4, CD25) 4. NK cells
what do CD4 cells do
activate macrophages, B cells, and other T cells via cytokines
what do CD8 cells do
directly kill cells when they are signaled to do so
what do CD4/CD25 cells do?
control activity of other immune cells, look out for self vs nonself, inactivate other cells that are killing the own body
what do NK cells do
directly kill cells without specificity, are always on and part of INNATE immune system
first line of (innate) immune defense?
physical barriers - skin, mucous membrane, saliva, tears, urine, stomach acid
2nd line of innate immune defense?
- complement 2. phagocytes like neutrophils, macrophages, basophils, eosinophils, NK cells
parts of innate immune system
- physical barriers 2. complement 3. myeloid granulocytes 4. NK cells *are not specific
parts of aquired immune system
- humoral immunity
- cellular cellmediated immunity - cytotoxic T and helper T
*very specific, distinguishes self from nonself
what cell responds first in the innate immune system
neutrophil
describe the types of acquired/adaptive imunity
- active - own Ab 2. passive - ready made Ab
describe passive immunity
- natural - maternal Ab like IgA from breast milk and IgG from placenta 2. artificial - injected by Dr.
describe active immunity
- natural - exposure to infectious agent 2. artificial - immunization
memory of innate vs adaptive immunity
innate has NO memory, adaptive has GOOD memory
specificity of innate vs adaptive immunity
innate is not specific, adaptive is VERY specific
what is humoral immunity
activated B lymphocytes that havfe differentiated into plasma cells and secrete IgA and IgG
differentiate lymphoblast from lymphocyte
lymphoblast has granules in cytoplasm, lymphocyte has centralized nucleus, clear small cytoplasm, nucleus is close to the size of a RBC
what do B lymphocytes express
IgM, recognizes specific antigens, which then tell B lymphocyte to proliferate into plasma cell which then secretes IgA and IgG
origin and location of B cells
bone marrow, stay in bone marrow until activated and enter circulation and colonize in CT, epithelia, lympoid nodules, and spleen
describe IgG
IS THE MOST ABUNDANT AB, secreted by plasma cells, secreted by mother in placenta
describe IgM
2nd highest Ab, secreted by B cell while it is inactive, the first Ab produced in immune response
describe IgA
secreted by plasma cells in digestive, respiratory and reproductive tracts, saliva, tears, breast milk (a little higher than IgM
describe IgD
may not even be existant, but would be on surface of B lymphocytem causes initial B cell activation
describe IgE
binds to mast cell surface in rhinitis inflammation, surface of basophils to recruit eosinophils to modulate histamine and heparin
describe process of B cell activation
initially, B cells secrete IgM and when antigen is presented to this, is triggers activation, proliferation and differentiation into platelet cells that secrete IgA and IgG
function of antibodies
- precipiates soluble antigens
- causes cellular agglutination
- opsonization - flagging down
- activates complement system or Ab themselves
- neutralization - keep adhesions from happening
- chemotaxis - attracting other cells
what is opsonization
Ab coating surface of microorganisms increasing the efficiency of phagocytosis
what is complement system
stimulates phagocytosis through opsonization and lysis or microorganisms
origin location T cells
originate in bone marrow, travel to thymus to differentiate and mature or die if not used
describe binding of T cells
they express T cell receptors which recognize and bind ONLY to MHC (major histocompatibility complex) VERY SPECIFIC
where are peyer’s patches found
ileum and appendix
what does the spleen do
filters blood
where are lymphatic nodules found
everywhere, in lymph node cortex
where are MALT found
walls of GI, respiratory, genital, urinary tracts
where are tonsils
- palatine - lots of crypts
- lingual - 1 crypt
- pharyngeal - no crypts
concentration of T and B lymphocytes in thymus
100% T cells
concentration of T and B in bone marrow
90% B 10% T
concentration of t and b in spleen
more B than T
concentration of T and B cells in lymph nodes
50%-50%
concentration of T and B cells in blood
more T cells because B cells secrete Ab that activate T cells, and are not as specific, T cells are faster in taking care of infections
significance of reticular connective tissue stroma
provides strong and resilient meshwork for lymphocytes, macrophages, plasma cells, and APC, so that infection/cells don’t spread where they shouldn’t be
what are the APC cells?
- B cells
- macrophages
- dendritic cells
*express MHCII to active T lymphocytes
describe macrophages
derived from monocytes, phagocytes, APC and cytokine producers, have large, central nucleus, and large irregular shape bc lots of lysosomes and well developed RER and golgi, usually stay in specified tissues around
what are langerhans cells
dendritic cells that proess and display antigens, on skin, can TRAVEL to lymph nodes, also derived from monocytes and are phagocytes
specific function of dendritic cells
convert antigens into MHC-peptide complexes and present on cell surface with MHCII to the T cells to be activated, once activated, move from tissue to lymph nodes to activate the T cells
what does lympoid tissue contain
reticular cells, lymphocytes, macrophages
describe reticular cells
pale central nucleus, prominent nucleolus and pale sparse cytoplasm, have branches of cytoplasm “dendrites”
classification of lymphoid tissue
- central lymphoid organs in thymus and bone marrow
- peripheral lymphoid organs in spleen,lymph nodes, tonsils, MALT
central lymphoid organs
supplies uncommitted t and b cell precursors that migrate into peripheral organs and tissues
*ANTIGEN INDEPENDENT*ACTIVATE DESPITE ANTIGENS
peripheral lymphoid organs
provide committed T and B cells that respond to specific antigens *need to be presented with an antigen to become active
what are lymphoid nodules/follicle
clusters of mostly B lymphocytes = primary functional subunit of all lymphoid tissue EXCEPT THYMUS
describe primary lymphoid nodules
dense group of mature, nonproliferating B lymphocytes (IgM)
describe secondary lymphoid nodules
have mantle zone of inactive lymphocytes (B and some T), and germinal center of proliferating lymphoblasts that have been activated by IgM/antigen
