Immunology I Flashcards
What is immunity?
The state of being insusceptible or resistant to a noxious agent or process.
What are first defences?
- Skin
- Tears, mucus, Saliva
- Stomach acid
- Cilia
- Urine flow
- ‘Friendly’ bacteria
What occurs in innate immunity?
LPS on bacteria only, these are known as PAMPs (pathogen associated molecular patterns)
TLRs detect PAMPs
Signal downstream effectors
What are Myeloid white blood cells?
Such as macrophages, express TLRs.
What are dendritic cells?
Specialised phagocytic cells
Express TLRs
Migrate to lymphoid tissues and stimulate T cells
What does activation of the immune system trigger?
- Inflammation: dilated blood vessels, sticky endothelium to catch WBCs. Fever stops pathogen proliferation and speeds up reactions.
- Recruitment of phagocytic cells: neutrophils (short lived), macrophages (long lived) eosinophils (attack larger objects)
What cells are used in innate immune system?
Neutrophils, mast cells
What cells are used in the adaptive immune system?
B cells, T cells
What cells are used in both the innate and adaptive immune systems?
Dendritic cells, macrophages
What is adaptive immunity?
A specific response for a specific pathogen.
Where are B lymphocytes produced?
Bone marrow
Where are T lymphocytes produced?
Thymus
What do B cells do?
Produce immunogoblins which are secreted by plasma cells and bind to antigens.
What types of T cells are there?
- Cytotoxic T cell: kill infected host cells
- T helper cells: release cytokines, to activate dendritic cells, B cells, cytotoxic T cells, macrophages.
- Regulatory T cells: suppress immune response.
What happens when an antigen binds to a specific cell?
Clonal expansion, proliferation, lots of antibodies produced.
What does immune tolerance mean?
Cells transplanted into adults are rejected and destroyed by T cells
Cells transplanted into babies are accepted
What percent of protein in plasma is antibodies?
20%
How many binding sites do antigens have?
2
What do constant domains do in antibodies?
Interact with the immune system
What do variable domains do in antibodies?
Make up the antigen binding sites.
What is the primary antibody repertoire?
Generates 1x10^12 antibodies
What is junctional diversification?
During joining of the gene segments, nucleotides are lost or inserted from the ends of the segments.
This may cause a frame shift.
What are the domains of a heavy chain in an antibody?
40 V domains
25 D domains
6 J domains
5 C domains
What are the domains of a light chain in an antibody?
40 V domains
5 J domains
1 C domain
Are T and B cells diploid or haploid?
Developing B and T cells are haploid, then they choose one allele to recombine (allelic exclusion)
