Immunology SBA Flashcards
What leads to DiGeorge syndrome
Infants with this syndrome lack a thymus and so have no circulating T-cells. They have a normal number of B-cells but cannot make an effective antibody response against most antigens. Caused by deletion of part of chromosome 22. Diagnosed- fluorescent in stiu hybridisation. Symptoms also include palatal abnormalities and learning difficulties -> SCID
What leads to Kaposi’s sarcoma
HHV8 - AIDS predisposes you for this condition
What leads to SCID - severe combined immunodeficiency
mutations in genes for cytokine signalling molecules e.g. IL-2 receptor and Jak3 (a protein kinase)
Other causes of SCID include RAG 1/2 and adenosine deaminase (ADA) mutations
Defect in T-cells
Definitive diagnosis for AIDS?
Reduction in CD4 T cells (below 200 microL-1)
Cell surface molecule that recognises LPS?
TLR4
Rearrangement after primary immune response
- somatic recombination in B
- cells driven by VDJ recombinase complex within heavy chain.
- V&;J with light chain (no D genes).
Also note affinity maturation – where antibody affinity is higher in secondary challenge.
What is thymic atrophy?
reduction in size of thymus, and consequent reduction in T cell production. Deficiency leads to SCID
What is ADA?
adenine deaminase - breaks down a key enzyme important for lymphocyte production. Deficiency leads to SCID. SCID is a defect in T-cells and has mutations.
caused by mutations in genes for cytokine signalling molecules e.g. IL-2
• RAG 1/2 and adenosine deaminase (ADA) mutations
Which Ig component is most polymorphic?
the variable region within the heavy chain as it contains VDJ genes. Note: light chain only contains VJ (no D genes)
What Ig component recognises LPS?
toll like receptors (mainly TLR-4).
NOD1;2 – peptidoglycan recognition.
RIG – viruses
What haplotype out of the list is most associated with autoimmune disorders
HLA
What causes granulation tissue?
macrophages surrounded by T cells - mycobacterial
type of hypersensitivity for SLE, systemic anaphylaxis and serum sickness
Systemic anaphylaxis – type I hypersensitivity
Serum sickness – type III hypersensitivity
Whitelock
Mg
Treg
suppresses other T-cells. Cytokine 3rd signal: TGF-B. Cytokines produced: TGF-B and IL-10
Preventing viral replication
acyclovir
Organ transplant
Alloreactive CD4 respond to HLA II
alloreactive CD8 respond to HLA I
Immunology molecules/receptors and their function - HLA, Ig, KIR
KIR are expressed on NK cells
HLA
particular variant of HLA gene more likely to get an autoimmune disease
GVHD
Allogenic-HLA matched
medical complication following the receipt of transplanted tissue from a genetically different person. GvHD is commonly associated with stem cell transplants such as those that occur with bone marrow transplants. GvHD also applies to other forms of transplanted tissues such as solid organ transplants. APC activation leads to target tissue destruction.
Graft tolerance immunosuppression
-corticosteroids; cyclosporin (immunosuppression)
Cyclosporin
> gingival overgrowth
What happens in XLA?
reduction in B cells
Which is the most polymorphic gene?
notes say:
HLA alleles – most polymorphic variants in the population
Cheat sheet says:
gene encoding T cell receptor
