Breaking self-tolerance in lymphopenia:
Can we do it?
Supervisor:
Senior
Research Officer
T
Cell Biology Group (group head, A/Prof B.Fazekas de St.Groth)
Centenary
Email: e.shklovskaya@centenary.usyd.edu.au
Phone
9565 6198
What is self-tolerance and who is
controlling it?
Put simply, self-tolerance is the
inability of an organism to mount an immune response against self-antigens. A
subpopulation of CD25+CD4+ T cells, termed regulatory T cells or Tregs, is responsible for preventing autoimmune diseases in
animals and humans. “Treg” is a common term for
several populations of regulatory T cells that differ in their ontogeny and
perhaps mechanism(s) of suppression. Conditions that favour
or hinder Treg functions are under the scrutiny of
many research groups in the world.
The mouse model: some background
facts
1) Mice double-transgenic for CD4 T cells expressing a given T cell
receptor, and for model antigen that these T cell recognise
(=self-antigen), do not develop autoimmune disease but instead have a large
proportion of antigen-specific Tregs.
2) When CD4 T cells expressing a given T cell receptor are adoptively
transferred into mice transgenic for the model antigen that these T cell recognise (=self-antigen), transferred T cells are deleted.
No autoimmine disease develops.
3) Similar to (2), when CD4 T cells expressing a given T cell receptor
are adoptively transferred into normal animals and then given a systemic antigen
(e.g. large dose of oral or intravenous antigen), transferred T cells get
deleted. No autoimmine disease develops.
4) When the same experiment (3) is performed in lymphopenic
animals (irradiated of lacking T cells due to a genetic manipulation), deletion
of adoptively transferred T cells in response to systemic antigen doesn’t
occur. Animals can show signs of a transient autoimmine-like
response, however they usually survive.
The goal of this project is to
look at the mechanisms of T cell survival and “autoimmunity” in lymphopenic (rag-/-) mice that are either transgenic for
model self-antigen (HEL:MCC) or receive a large “deletional” dose of model antigen (MCC). T cells expressing
MCC-specific T cell receptor will be adoptively transferred into these rag-/-
hosts, and the fate of transferred T cells, as well as animals’ health will be
monitored. Specifically, we will concentrate on the conditions that favour the development of T cells with regulatory
properties within the transferred T cell population.
Mouse in vivo techniques (including various ways of
vaccination and intravenous injections, creating mouse chimeras, isolation of
mouse lymph nodes and spleens, labelling of cell suspensions with CFSE dye and
T cell adoptive transfer)
Nine-colour flow cytometry–
remember, we have the best Flow facility in
In vitro assays (T cell proliferation, cytokine
re-stimulation)
Monoclonal antibody
purification if required