Card Set Information
What does the thoracic duct drain into?
Positive T cell selection
Selects for T cells that can bind MHC
Occurs in cortex of thymus
Negative T cell selection
Selects for autoreactive T cells
Occurs in medulla of thymus
Where are small antigenic peptides attached to MHC I?
What is significant about CD5+ B cells?
They have not undergone class switching, and can only produce IgM
Function of perforin and granzymes
Perforin delivers NK cell granule contents into infected cells
Granzyme activates serine proteases, which triggers apoptosis
What activates T helper cells?
Foreign antigen presentation on MHC II, with help of B7 costimulatory molecule
Which MHC activates cytotoxic T cells?
MHC I (presents viral or self antigens)
Where is the CD40 ligand located, and what does it do?
CD 40 ligand on T helper cell membrane
Mediates AB class switching
Function of immunoglobulins alpha and beta on B cell membrane
Transduce AG binding signal to cytoplasm
Difference between pro-B cells and pre-B cells
Heavy chain rearrangement occurs in pro-B cells
Light chain rearrangement occurs in pre-B cells
Randomly inserts nucleotides between D and J regions during DNA synthesis to increase affinity of AB for AG
Used as a marker for ALL
Which antibody does not undergo somatic hypermutation?
What is a thymus independent antigen?
Thymus independent antigens lack a peptide component, so cannot be presented by MHC to T cells. They stimulate release of IgM only, and do not activate memory
CD21, found on B cells
C3b and IgG
Recurrent pyogenic and respiratory infections
Increased susceptibility to type III hypersensitivity reactions
DAF helps prevent complement activation against self-cells. Is deficient in PNH.
How do interferons kill viruses?
They induce production of a ribonuclease that degrades viral mRNA
What type hypersensitivity reaction are serum sickness and arthus reaction?
Present with fever, urticaria, and arthralgias, 5--10 days after antigen exposure
Hypersensitivity reactions: Grave's and Hashimoto's
What are the type IV hypersensitivity reactions?
6 month old boy presents with recurrent bacterial infections, decreased B cells, and decreased immunoglobulins
Defect in BTK tyrosine kinase gene
B cell maturation is impaired
Baby presents with severe pyogenic infections and increased IgM with no other immunoglobulins
Caused by defective CD40 ligand on T helper cells
Patient with a history of respiratory infections experience anaphylaxis after a blood transfusion
Selective Ig deficiency, due to defective class switching
Most common is IgA deficiency
Patients often develop antibodies against the missing Ig--so don't transfuse!
Which Ig do Di George patients have?
IgM only, since T cells are needed for class switching
Patient has recurrent disseminated mycobacterial infections and low interferon gamma
IL12 receptor deficiency
(IL12 is secreted by macrophages and activates T helper 1 cells)
Patient presents with staphylococcal abscesses, retained primary teeth, eczema, and increased IgE
T helper cells cannot produce interferon gamma, which inhibits neutrophil response to chemotactic stimuli
Normally, IFN gamma inhibits T helper 2 cells--too many T helper 2 cells results in elevated IgE
Primary defense against cutaneous and hematogenous candida infection
T cells protect against cutaneous candida
Neutrophils protect against disseminated candida
Name 3 causes of SCID
Defective IL2 receptor (X linked)
Adenosine deaminase deficiency
Missense mutation in RAG
Patient presents with TTP, recurrent infection, and truncal eczema.
Progressive B and T cell deletion, due to an XR mutation in cytoskeleton proteins
Patient presents with cerebellar ataxia, spider angiomas, and IgA deficiency
Ataxia telangiectasia, caused by defective DNA repair enzymes
A baby presents with recurrent bacterial infections and delayed separation of umbilicus
Defective integrin protein on phagocytes impair ability of leukocytes to adhere to endothelium
Patient presents with recurrent staph and strep infections, pale skin, and peripheral neuropathy
An AR defect in microtubule function impairs phagocytosis
Patient presents with a history of recurrent infections by catalase positive organisms (staph, E. coli, aspergillus)
Addition of nitroblue tetrazolium to blood sample does not make sample turn blue
Due to lack of NADPH oxidase
Mechanism and side effect of cyclosporine
Inhibits calcineurin, which prevents release of IL2, thereby blocking T cell activation
Major side effect is nephrotoxicity, which can be controlled with mannitol diuresis
Mechanism and side effects of tacrolimus
Binds to FK binding protein and inhibits IL2 release
Causes nephrotoxicity, peripheral neuropathy, and hyperglycemia
Monoclonal antibody against CD3, inhibits T cell signal transduction
Binds to MTOR, inhibits T cell proliferation in response to IL2
Mycophenolate mofetil (MMP)
Inhibits de novo guanine synthesis
Monoclonal antibody against IL2 receptor
What is oprelvekin used for?