Day 2.2 Immuno Flashcards
LN
Upper limb, lateral breast
Axillary LN
LN
Stomach
Celiac LN
LN
Duodenum, jejunum
Superior mesenteric LN
LN
Sigmoid colon
Colic –> Inferior mesenteric LN
LN
Rectum (lower part), anal canal above pectinate line
Internal iliac LN
LN
Anal canal below pectinate line
Superficial inguinal LN
LN
Testes
Superficial and deep plexuses –> para-aortic LN
LN
Scrotum
Superficial inguinal LN
LN
Thigh (superficial)
Superficial inguinal LN
LN
Lateral side of dorsum of foot
Popliteal LN
What does the right lymphatic duct drain?
Right arm and right half of head
So if you obstruct R lymphatic duct, will get non-pitting edema of R arm and R head
What does the thoracic duct drain?
Everything except the R arm and R head (which are drained by the R lymphatic duct)
Where does the thoracic duct enter back into circulation?
Jn of L. Subclavian in the IJV
IL-2
T cell stimulator
Anti-IL2 drugs will shut down immune system
IL-10
Inhibits T cells and Macrophages
IFN-gamma
Stimulates macrophages
Il-4 and IL-5
Stimulates B cells
What are the components of the adaptive immune system?
T cells
B cells
Ab
Fns of lymph node
non-specific filtration by macrophages
storage and activation of B and T cells
Ab production
LN Follicles
Site B cell localization and proliferation.
Follicles are in outer cortex.
Where are Tcells found in LN?
Paracortex (bt follicles and medulla)
How do T and B cells enter the LN from the blood?
Through high endothelial venules in the paracortex of the LN
Where is the paracortex located w/in the LN?
Region of cortex, bt the follicles and the medulla.
Which part of the LN becomes enlarged during extreme cellular immune response?
Paracortex
Which part of the LN is underdeveloped in pts with DiGeorge syndrome?
The paracortex.
DiGeorge = no Tcells
Paracortex houses Tcells
No Tcells = sml paracortex
Where are the plasma cells located in the LN?
Medullary cords (medulla)
Where are macrophages located in the LN?
Medullary sinuses (medulla)
Where are Tcells located in the spleen?
PALS periartierial lymphatic sheath
and in the red pulp
Where are Bcells located in the spleen?
Follicles and white pulp.
T cell location in LN, Spleen
LN: Paracortex
Spleen: PALS
B cell location in LN, Spleen
LN: Follicle
Spleen: Follicle
What is the fn of macrophages in the spleen?
Remove encapuslated bacteria
SKHNSB
Which pts are more susceptible to encapsulated bacteria? What can be done to help them?
Asplenic pts
Vaccinate them.
What vaccines do asplenic pts need?
Pneuomvax (pneumococcus, against S. pneumonia)
HiB
Meningiococcal
Why are asplenic/splenic dysfn pts susceptible to encapsulated bacteria?
They have decreased IgM, which means decreased complement activation, which means decreased C3b opsonization, which means increased susceptibility to encapsulated.
Why are pts asplenic?
Sickle cell (auto-infarct of spleen) Trauma
What is the Rx for hereditary spherocytosis?
Remove spleen (this is one option)
Post-splenectomy, what do RBCs look like?
More Howell-Jolly bodies (RBCs with nuclear remnants)
More target cells (excess mbr relative to amt of Hb)
Also will have thrombocytosis (high PLT count)
What is the classic presentation of infarction on CT?
Wedge/triangular lesion, with point/apex toward center of body and base of triangle toward outside/body wall
Why does lymph fluid have a milky appearance?
It is high in Chylomicrons, high in Triglycerides
Thymus is site of what?
Tcell differentiation and maturation.
Where does the thymus come from embryologically?
Epithelium of 3rd brachial pouches (IMP!)
What is the structure of the thymus?
Inner medulla, outer cortex.
Medulla = middle = mature Tcells
Where does Tcell selection occur in the thymus?
Corticomedullary jn.
Tcells start as immature in cortex and mature as they go inward to medulla. Undergo selection as they mature.
What is positive and negative selection of Tcells in the thymus
Positive = MHC restriction Negative = nonreactive to self
Where do Tcells and Bcells mature?
Tcells- thymus
Bcells- bone marrow
What cells make up the innate immune system?
Neutrophils Macrophages Dendritic cells (APCs- present to neutrophils and macrophages) NK cells Complement. Each cell can do many different jobs.
What is the only lymphocyte that is part of the innate immune system?
NK cells.
The other lymphocytes (Tcells, Bcells) are part of the adaptive immune system.
Innate vs Adaptive: which is fast and non-specific?
Innate.
Innate is also germline-encoded, whereas adaptive is not, it is learned.
Vaccines affect which, innate or adaptive?
Adaptive
Adaptive is the only system with memory.
How do NK cells kill virus-infected cells?
They use perforin and granzymes to cause apoptosis (in both virally infected and in tumor cells)
Which cytokines enhance NK cells?
IL-12
IFN-alpha
IFN-beta
Virus-infected cells release IFNs. What do IFNs signal?
They induce NK cells
They induce neighbor cells of the virus-infected cell to inhibit viral protein synthesis
What signals induce NK cells to kill?
Non-specific activation signals on the target cell, and/or absence of MHC-I on cell surface. MHC-I is found on most every cell in the body, so no MHC-I means it’s not self.
What are the fns of B cells?
Make Ab
IgG Ab opsonize bacteria and neutralize viruses
IgE Ab mediate Type I HPS allergic rxns
IgG Ab mediate Type II HPS cycotoxic rxns and Type III HPS Immune complex rxns
Ab cause hyperacute organ rejection
What are the fns of T cells?
CD4+ Tcells help B cells make Ab
CD4+ Tcells make IFN-gamma, which activates macrophages
CD8+ Tcells kill virus-infected cells directly (the are cytotoxic)
Responsible for Type IV HPS- cell-mediated delayed HPS
Responsible for acute and chronic organ/allograft rejection
After positive selection of Tcells in the cortex of the thymus, what cells are left?
Start as CD4+ CD8+ and after pos selection are either CD4+ 8- or CD4- 8+
Depending on whether they bind MHC-I (CD8+) or MHC-II (CD4+)
Which happens first, pos selection or neg selection of Tcells?
Positive, then negative
What is negative selection?
Tcells that react to self are apoptosed. Occurs at corticomedullary jn
What is the fn of CD8+ cells?
Cytotoxic Tcells Kills 3 things: Virus-infected cells Neoplastic cells Donor graft cells Similar to the NK cells of the innate immune system (NK cells are also lymphocytes)
How do cytotoxic CD8+ cells kill?
By apoptosis.
They rls cytotoxic granules which have perforin and granzyme.
Perforin helps perforate and deliver content of granules into cells.
Granzyme is a serine protease that activates apop w/in cell.
Cytotoxic CD8+ and NK cells are similar, but they differ with regards to MHC-I recognition. How?
NK cells recognize the absence of MHC-I, and kill cells with out it, since they are non-self.
Cytotoxic CD8+ cells use their CD8+ to recognize MHC-I on virally infected cells.
Do cytotoxic CD8+ cells cause inflammation?
No they cause apoptosis.
What cytokine induces CD4+ Thelper cells to become Th1?
IL-12
IL-12 is produced by virally infected cells
What cytokine induces CD4+ Thelper cells to become Th2?
IL-4
IL-4 is produced by Th2 cells (pos feedback)
What cytokines do CD4+ Th1 cells secrete?
IL-2
IFN-gamma
Which cytokine inhibits Th2 production?
IFN-gamma, secreted by Th1 cells
What does IL-2 stimulate?
Tcells (e.g. CD8+ cytotoxic Tcells)
What does IFN-gamma stimulate?
Macrophages
Also inhibits Th2 production.
What cytokines does CD4+ Th2 produce?
IL-4
IL-5
IL-10
What do IL-4 and IL-5 do?
Stimulate B cells to make Ab (IgE > IgG)
What does IL-10 do?
Inhibits Th1 and macrophages
What cytokine inhibits Th2 production?
IFN-gamma (secreted by Th1)