Immunology Flashcards
What are some substances secreted by skin and mucous membranes that act as a barrier to pathogens?
- Mucins
- Protease inhibitors
- Peroxidase
- Antimicrobial peptides
- Acid pH (3-5)
- Lysozymes
- Histatins
Which cytokines are released by phagocytise cells?
IL-1, IL-6, IL-8, TNF
What are 11 key conserved molecular patterns?
- Lipopolysaccharides (on gram -ve bacteria cell wall)
- Bacterial lipoproteins and lipopeptides
- Lipoteichoic acids (on gram +ve bacteria cell wall)
- Porins (on gram -ve bacteria cell wall)
- Peptidoglycans
- Mannose-rich glycans Flagellin protein
- N-formylmethionine
- Zymosan
- Bacterial and viral nucleic acid
- Double stranded viral RNA
- Single stranded viral RNA
What are the four receptor types (pattern recognition receptors) that recognise and bind pathogen associated-molecular patterns (PAMPs)?
- Cell surface (facilitate uptake of pathogens into cells or act as signals for cell movement or destruction)
- Toll-like receptors (activate intracellular signalling pathways)
- Endosomal toll-like receptors (includes TLR-3, 7, 8, 9)
- Cytosolic
a. RIG-like receptors
b. NOD-like receptors
What are natural killer cells?
Cells involved in the non-specific cytotoxic killing of virus-infected, damaged or cancerous cells.
How are NK cells able to recognise and kill target cells?
- Balance between activating and inhibiting signals (decreased MHC expression on a cell leads to decreased inhibitory signal)
- Ab-dependent cellular cytotoxicity mechanisms (they induce apoptosis via perforin and granzyme release)
Where are IgA antibodies found? How do they work?
External secretions and blood
They attach to and inactivate foreign pathogens (block key attachment proteins)
Where are IgE antibodies found? What do they do?
Blood
Attach to mast cells and basophils (lead to release of vasoactive amine, cytokines and enzymes)
What are IgM antibodies and what do they do?
They fix complement and cause death of cells
Produced early during immune response
Pentametric—> agglutination
What is the predominant antibody in serum?
IgG
Some fix complement, others cross placenta, others bind to cells via Fc receptors
What antibodies are found in colostrum?
M, G and A
What characterises secondary immune responses?
Faster More antibodies Different antibodies Higher affinity T cell help
CD8 cells recognise what class of MHC?
MHC class I
Describe the composition of the MHC class I molecule?
Has an alpha chain and a B2-microglobulin.
Alpha is variable and forms the BBQ and sausages to capture
B2-microglobulin is constant among individuals and does not interact with individual
On which cells are MHC II molecules expressed?
How do their chains differ to MHC I molecules?
Antigen presenting cells (macrophages, dendritic cells, B cells).
Alpha and beta chain are both variable and they both form the BBQ 🍖
What is a MHC haplotype?
The combination of MHC genes present on a particular chromosome.
An individual can have 6 MHC class I molecules on their cells surface. This is because they get 3 alpha chain alleles each from their mum and dad. Why is there higher diversity with the number of MHC class II molecules if they get 4 each?
Because each alpha chain can associate with several beta chains
What is clonal selection theory and what are some reasons why is it wrong?
The theory that antigens select the antibody to be made by each T cell. This is wrong because:
There is a need for different isotopes without changing antigen specificity.
The theory requires Abs to be soluble and membrane bound.
B cells need to become memory cells
What are the two light chain variants of an immunoglobulin?
Lambda and kappa (variable, joining and constant domains)
Upon activation, B cells differentiate into…?
Blast cells which then become IgM-producing plasma cells
How are soluble antibodies made?
Replacement of the last 40 or so mostly hydrophobic amino acids by 20 hydrophilic amino acids
How does class switching occur?
RNA splicing (DNA looping and recombination)
How are monoclonal antibodies produced and why are they useful?
Via fusion with myeloma cells. Allows diagnostic testing for specific antigens.
What is antigen processing?
The process of transforming antigens to small peptides to present to T cells in association with MHC
What makes up the thymus?
I,mature T cells from the bone marrow and the thymus stroma (including thymic dendritic cells, epithelial cells and macrophages)
What are cytokines?
Small soluble messenger proteins involved in the communication between cells (particularly those of the immune system).
What is pleitrophy?
The ability of cytokines to act on different cell types
What are some applications of cytokines in vet med?
Vaccine adjuvants Antimicrobials Therapeutics Growth promoters Diagnostics
