Lecture 12 - Adaptive Immune Response (Effector Phase) Flashcards
Which molecules on APCs present Extracellular microbes antigens to naive T cells?
MHC Class II
Which Naive T cells have extracellular antigens presented to them by MHC Class II molecules?
CD4+ T cells
What type of Immunity do activated CD4+ cells produce?
Humoral immunity (antibodies)
Which molecules on APCs present Intracellular microbes antigens to naive T cells?
MHC Class I molecules
Which Naive T cells have intracellular antigens presented to them by MHC Class I molecules?
CD8+ T cells
What type of Immunity do activated CD8+ cells produce?
Cell-mediated immunity (Cytotoxic T cell response)
Once an APC has captured a microbe where does it migrate to and what part of this area does it go to?
Lymphatics/lymph node
Parafollicular cortex
Why does an APC that’s captured a microbe migrate to the parafollicular cortex?
Has many T cells here so activate the maximum amount of T cells
Where are T and B cells produced?
Bone marrow
Where do T cells mature?
Thymus
Where do B cells mature?
When they come into contact with antigens in the blood
What is lymphadenopathy?
When the lymph nodes swell
Why can lymphadenopathy happen with infection?
Swell in infection due to T cells and B cells proliferating
What organ is absent/poorly developed in Digeorge syndrome?
Thymus or Spleen
Why is a patient with Digeorge syndrome immunocompromised?
No poorly developed thymus
This is where T cells mature
So very few or no mature T cells
What are antigen receptors on T lymphocytes called?
T Cell Receptors (TCR)
Where are the 2 extracellular regions of a T cell receptor?
Variable region
Constant region
Which region of a T cell receptor does the pathogens peptide/antigen bind to?
Variable region
What enables the variable regions of T cell receptors to be able to recognise many antigens?
Different segments of genes are randomly expressed generating many combinations that can recognise many different antigens
If T cell receptors can recognise all antigens/peptides, what limits our T cells activating against all pathogens?
T lymphocytes only get activated by peptides that are presented by Antigen Presenting Cells (APCs)
What MHC molecule must present a peptide for Helper T cells (CD4+) to recognise it?
MHC Class II
What MHC molecule must present a peptide for Cytotoxic T cells (CD8+) to recognise it?
MHC Class I
What are the 3 signals on an APC that is needed to activate a T cell?
Signal 1 = MHC molecule with peptide
Signal 2 = B7
Signal 3 = Cytokines
What structure does the peptide attached to the MHC molecule on the APC bind to on the T cell?
T cell Receptor at the variable region
