Host defense against infection Flashcards
Summarise the sequence and timing of events during infection Summarise and give examples of the roles in host defense taken by: physical, chemical and mechanical barriers; antigen presenting cells; and immune regulatory mechanisms Define, explain and compare: innate versus adaptive immunity; humoral versus cellular immunity; defense against bacteria, viruses and fungi; and defense at mucosa versus the skin
What are the defences at mucosa surfaces?
Mucous, cilia, sneezing and coughing, rapid cell turnover.
What are the sequential actions of the immune system? What happens to specificity, breadth and learning as the response goes along the sequence?
Refer to photo.
What are the three main types of interferons and what do they do? What interferons are involved in each type? (x3 and x1) (Can be grouped into two – x3 and x1.)
Type I/III: IFN alpha, beta, lambda — activate Natural Killer cells, upregulate MHC and induce anti-viral state. Type II: interferon gamma — it is the Th1 cytokine - pro-inflammatory and antiviral.
What are interferons? What particular pathogen?
A type of cytokine, that communicates with other cells to trigger a protective immune response against viruses – they are ANTI-VIRAL.
Why is there variability in the constant region of an antibody? (x2) Where is there variability?
Differs by antibody CLASS: to interact with cells and form multimers.
Why is there variability in the variable region of an antibody?
Specific to epitope/antigen – so can mediate a response in the pathogen = precipitation, opsonisation and neutralisation.
What is each TCR specific to?
A specific combination of MHC and peptide at HIGH AFFINITY.
CD4+ cells: Type of cell? MHC? Where are the MHCs found? Mechanism? !!!
CD4+: Helper cells, MHCII on specialised APCs. ACTIVATE. CD8+: Cytotoxic cells, MHCI on non-specialised APCs. KILL.
What pathogen type are each T-helper subtype suited for?
Th1: anti-viral/bacterial. Th2: allergies. Th17: fungi/bacteria.
