USMLE Road Map by Dr. Parmely Flashcards
What is the role of IFN-alpha and IFN-beta?
Blocking virus replication within cells
What is the role of INF-gamma?
Potent activator of macrophages for killing of intracellular bacteria or fungi
What is the role of mucocilliary movement in the lung epithelium and peristalsis of GI tract involvement in the immune system?
These move microbes and other foreign agents across mucosal surfaces and out of the body
After the microbe is uptaken and subsequent fusion with a lysosome yields what?
Phagolysosome
Chronic granulomatous disease is caused by a mutation in what?
NADPH oxidase - leads to problems with the oxidative burst
What are the main functions of TNF-alpha?
Fever, leukocyte adhesion to endothelium, acute phase protein synthesis, oxidative burst, disseminated intravascular coagulation and shock
What are the main functions of IL-6 and IL-1?
Fever, leukocyte adhesion to endothelium, acute phase protein synthesis and B lymphocyte co-activation
IFN-alpha and beta have what role against viruses?
Blocking viral replication within cells
What is the role of IFN-gamma?
Activation of macrophages for the killing of intracellular bacteria and fungi
What is the role of CRP?
Binding to bacterial surface and activation of complement, serves as an opsonin
What is the cause of the ESR in response to inflammation?
Increased fibrinogen
Patients with hereditary angioedema have what?
Significantly decreased levels of plasma C1 inh, which is an important regulator of the classical pathway
Complement peptide C3d binds to what?
B cell coreceptor CR2
Can severe congenital neutropenia be treated with G-CSF?
No, this is a defect in the receptor for G-CSF
What is interesting about a patients thymus with DiGeorge’s syndrome?
Patients with DiGeorge syndrome lack a thymus
Where are B cells concentrated in lymph nodes?
Primary and secondary follicles within the cortex of lymph nodes
Where do memory B cells develop in the LN?
Germinal centers of the cortex
Where are T cells located in the LN?
Primarily in the paracortex where they associate with DCs
Secreted antibodies exit the lymph node via?
Efferent lymphatics
Use of the invariant chain is associated with what MHC class presentation?
MHC class II presentation
Use of TAP protein is associated with what MHC class presentation?
MHC class I
Patient presents with sever lymphopenia. Flow cytometry demonstrates low number of CD3 lymphocytes but normal IgM. What could be the disease?
DiGeorge Syndrome
What two clinical abnormalities would be associated with a defective CD18 protein?
Defective leukocytosis and recurrent bacterial infections.
A patient presents with lymphocytosis and enlarged lymph nodes. 90 percent of the patients bone marrow cells stain with CD3. What is a possible diagnosis?
T cell leukemia
What is the best explanation for the reason that patients with antibody deficiencies can often present with the same types of infections as patients with phagocytic cell deficiencies?
Antibodies are important opsonins that promote microbe recognition by phagocytes
What is a Coombs test?
To determine if an anemia has an immune basis by determining whether IgG antibodies are present on the patients erythrocytes
What is the primary benefit of IVIG?
In immunodeficient patients it is to provide protection against extracellular microbial pathogens or their toxic products
Dimeric IgA is associated with what?
Intestinal mucosa and is translocated across the mucosal epithelium. This is made possible by the secretory component
What mediates opsonic activity of IgG antibodies?
The Fc fragment on antibodies bindgs to the Fc receptor on phagocytic cells
RAG1/2 is responsible for what?
VDJ recombination
Mutations in Rag1 or Rag2 genes lead to what disease?
SCID - characterized by a T-B-NK+ lymphopenia.
What is allelic exclusion?
When successful rearrangement at one allele is achieved a signal is created that inhibits further rearrangements at the homologous allele
If both alleles fail to productively rearrange what will happen?
They will most likely undergo apoptosis
In order to generate junctional diversity nucelotides are added by what enzyme?
TdT
Patient presents with recurrent bacterial infections that come back a week after finishing antibiotics. Lab test show mild neutropenia, low levels of IgG and IgA, and increased levels of IgM. When given a vaccination they make no detectable IgG. What could be the underlying cause of this?
Failure of her B cells to undergo Ig class switching.
A population of plasma cells from a patient who was recently immunized with a protein vaccine has been isolated. Her cells secrete IgG but lack membrane IgG. What accounts for this?
Differential RNA processing favors the synthesis of a secreted form of gamma-heavy chains
Th1 cells have a role in?
Cytokine production that is primarily associated with cell-mediated immunity; cytotoxic T cell growth and macrophage activation
Th2 cells have a role in?
Production of cytokines that is primarily associated with humoral immunity; B cell activation, proliferation and differentiation and Ig class switching
IL-4 induces what Th response?
IL-4 induces Th2 response
IFN-gamma is an important inducer of what Th response?
Th1 response
What is the transcription factor responsible for Th1 development?
T-bet responds to IFN-gamma promoting Th1 development
What transcription factor is responsible for Th2 development?
GATA-3 activation leads to Th2
Patient was given cyclosporine following organ transplant. 3 wks later patient developed a cytomegalovirus infection. A decrease in what response would be the best explanation for this opportunistic infection?
Cyclosporine inhibits the phosphatase calcineurin - important in activating NFAT. NFAT regulates cytokine genes in T cells including those that coinduce virus specific CD8 T cells to differentiate.
If you were to design an experimental therapy directed at reducing cytokine production in allergic responses what would be a good target for this?
IL-4
It plays a central role in the development of allergy by promoting class switching to IgE and inducing more Th2 cells to produce IL-4
Is Lck involved in TCR or BCR signaling?
TCR
What is the TCR signaling pathway?
Lck phosphorylates ITAMs (zeta chains) leading to ZAP-70 then PLC-gamma-1
Louise inhabits zoo prohibitly
What is the BCR signaling pathway?
Lyn - ITAMs (Ig-alpha and beta) - Syk - Btk - PLC-gamma-2
Lonnie I Sick Because Pineapple
