Lecture: Infection and Immunity
Date: Thursday 15th February
Time: 11am – 12pm
Antigen Processing and Presentation
Last week we discussed B cells, antibodies, how we produced them and how we secrete
different classes of antibodies. Today we are going to discuss T cells, which need to see MHC
molecules that hold a small peptide of collagen and only then can the t cell become
activated. Only a few types can present to T helper cells to become activated. Whereas
cytotoxic t cells, can produce antigens in any cell in our body. This makes sense as any cell in
our body can become infected, so this process needs to be possible in all cells with a
nucleus.
Learning objectives:
- Histocompatibility gene complex (Histo = skin)
- The cytosolic pathway of antigen processing
- What are immunoevasions? Most pathogenic viruses have methods to get around
the immune system which prevent the cytosolic pathway processing.
- The endocytic pathway: only antigen presenting cells use this pathway, activating
helper t cells.
- Toll like receptors (TLRs): on the surface of a membrane, on an antigen presenting
cell. These recognise the pathogen and switch on the correct immune response.
- B cells processing and presenting antigen
MHC Variability
Case study: Cheetahs MHC variability went down to nothing. From a few pairs we were able
to build up the cheetah population. Now cheetahs have almost identical MHC factors, luckily
the human population has a varied range of MHC. Stopping the population from dying from
a virus.
Human Leukocyte Antigen (HLA):
Class 1: A,B and C
Class 2: DP, DQ, DR
Diversity: 6 different types of class 1 HLA molecules and 12 different types of class 2 HLA
molecules. We have huge numbers of Alleles in the human population.
We get our haplotype from our mother and father; these are both dominant and can
present antigens to our immune system. Four children from the same parents will have
slightly different MHC molecules. This makes it difficult to donate skin grafts to others. There
is something on the surface of skin cells that can’t produce compatibility, MHC molecules.
MHC 2 is found on antigen presenting cells.
Mate selection of MHC
1
Date: Thursday 15th February
Time: 11am – 12pm
Antigen Processing and Presentation
Last week we discussed B cells, antibodies, how we produced them and how we secrete
different classes of antibodies. Today we are going to discuss T cells, which need to see MHC
molecules that hold a small peptide of collagen and only then can the t cell become
activated. Only a few types can present to T helper cells to become activated. Whereas
cytotoxic t cells, can produce antigens in any cell in our body. This makes sense as any cell in
our body can become infected, so this process needs to be possible in all cells with a
nucleus.
Learning objectives:
- Histocompatibility gene complex (Histo = skin)
- The cytosolic pathway of antigen processing
- What are immunoevasions? Most pathogenic viruses have methods to get around
the immune system which prevent the cytosolic pathway processing.
- The endocytic pathway: only antigen presenting cells use this pathway, activating
helper t cells.
- Toll like receptors (TLRs): on the surface of a membrane, on an antigen presenting
cell. These recognise the pathogen and switch on the correct immune response.
- B cells processing and presenting antigen
MHC Variability
Case study: Cheetahs MHC variability went down to nothing. From a few pairs we were able
to build up the cheetah population. Now cheetahs have almost identical MHC factors, luckily
the human population has a varied range of MHC. Stopping the population from dying from
a virus.
Human Leukocyte Antigen (HLA):
Class 1: A,B and C
Class 2: DP, DQ, DR
Diversity: 6 different types of class 1 HLA molecules and 12 different types of class 2 HLA
molecules. We have huge numbers of Alleles in the human population.
We get our haplotype from our mother and father; these are both dominant and can
present antigens to our immune system. Four children from the same parents will have
slightly different MHC molecules. This makes it difficult to donate skin grafts to others. There
is something on the surface of skin cells that can’t produce compatibility, MHC molecules.
MHC 2 is found on antigen presenting cells.
Mate selection of MHC
1
