(04) MHC Flashcards
LET THYIS BE THY GUIDSE
What cells dictate what the challenge of the immune system is going to be?
What is required for T cell to interact with epitope?
- MHC molecules are essentially ____, in that they present epitopes to the ______ - to see idf somthing needs to be done
- T cells
- MHC
- cops, judge (T cells)
- Can T cells see whole antigen?
- If cytotoxic T cells have a receptor that recognizes the epitope - what will happen?
- endogenous are type what?
- exogenous?
- How can cytotoxic t-cell be represented?
- How can helper T-cells be represented?
What type of T cell does MHC class 1 hook up with?
What type of T cell does MHC class 2 hook up with?
- No it must be processed and then presented on MHC molecule
- it will kill the cell presenting the epitope via MHC
- I
- II
- Tc, CTL, CD8+
- TH, CD4+
- Cytotoxic T cell (CD8)
- Helper T cell (CD4)
(MAJOR HISTOCOMPATIBILITY COMPLEX)
- A system of gene products used for ______ recognizing and _____ foreign antigens. These antigens can be from within host cells (____) or from extracellular sources (_____). Both self and non-self antigens are constitutively ____ and _____.
The system function to recognize a wide variety of epitopes:
_____ - several genes exist for a given MHC class
_____ - a large number of allels exist for a given gene
_____ - will bind a range of similar epitopes
- Except for the ____ locus, each locus has many ____. Each allele can present processed antigens to T cells
- T and B cells have evolved to recognize any antigen (within an _____) - MHC hasn’t for every individual - but has for a given _____
- specifically, eliminating, endogenous, exogenous. processed and presented
- polygenic
- polymorphic
- promiscuous
- DRa, alleles
- individual, population
(MHC REGIONS)
_____ - encode a single chain - present endogenous genes to _____
_____ - encode two chains - present exogenous genes to _____
_____ - encode which five things?
Strange thing about MHC complex is that the different regions have been shuffled in different ways across different species - but that the whole region has stayed intact.
All verterbrates possess MHC genes, but the _____ of genes within each class varies. Many ______ exist within the locus.
- Class I, cytotoxic T cells
- Class II, helper T cells
- Class III, cytokines, heat shock proteins, Ag processing, transport proteins, complement proteins
- number, pseudogenes
Class I and II MHC molecules _____ present the antigen on the surface of the cell. _____ is a loose term for all otehr genes in the MHC region.
Many of the class III genes econde proteins involved in ____ and ____. Other genes encode ____ and ____. Interestedingly, several ______ receptors are encoded in this region and may influence ___ secltion.
- physically, Class III
- processing, transport, complement, cytokines, mate
(MHC CLASS 1 STRUCTURE)
- _____ expressed on the surface of ___ nucleated cells
- encodes a _____ AA non-covalently associated with _____ (what is thsis purpose).
Which domains form the pocket?
- constitutively, all
- single, B2-microglobulin (B2m), structural
- alpha 1 and 2
(MHC class 1 structure)
1 side of hotdog bun = _____
second side of hotdog bun = ____
hotdog = ____
- alpha 1 domain
- alpha 2 domain
- epitope
(MHC Class-I function)
- Because this class communicates with cytotoxic T cell - it causes ____
- Class I recognition is especially important for _____. The ____ proteins are produced within the host cell and are displayed on the surface in context ith MHC class 1.
- cell death
- virus-infected cells, viral
(MHC class II antigens)
- expressed primarily on _____.
- Consist of _____ polymorphic chains (alpha and beta) that fold together to form a _____ for processed antigens
- one side of hotdog, other side, hotdog
- immunocytes
- two, binding pocket
- beta 2 domain of the beta chain, alpha 1 domain of the alpha chain, processed antigen (epitopes are a little larger 8-16 AA)
(MHC Promiscuousness)
- The MHC binding pocket is much more _____ thatn the Ab or TCR binding pocket. Essentially, there are many _____ that fit, requiring only the conservation of the _____ that interact with the antigen ______ withing the MHC binding pocket
- Even though there are only a few pockets - can still recognize many difernt antigens
- flexible, peptides, anchor residues, contact
(MHC Class II - FUNCTION)
- present ___ Ag to ____
- This activates the _____ for the purpose of inducing the immune response, including ____, _____, and _____.
- exogenously produced, Helper T Cells (CD4)
- T helper cells, antibody production, marcophage activation, cytokine cascades
- The MHC class I binding pockets hold ____ AA while class II holds ____ AA
- they also have ____ specificity
- 8-12, 13-20
- broad
(MHC ARS Hypermutation sites)
- In orde to generate populations with the ability to present almost every possible _____, the MHC has a ___ rate of mutation (many _____) in the peptide biding cleft. This changes the specificity between _____ as to the exact structure that will fit into the cleft.
The most varaiation of MHC occur in the _____.
- antigen, high, alleles, alles
- binding pocket coding sequences
What species have limited MHC diversity? what does this mean?
- cheetahs, tasmanian devils (facial tumor) , giant pandas
- limited diversity can put populations at risk