T cells and cytokines Flashcards
What branch of the immune system are T cells a part of?
The innate and adaptive immune system
NK cells and gamma delta T cells form part of both
What differentiates a naive T cell from an activated T cell?
Naive T cells become activated once they encounter their specific antigen
What do T cells do in the body before they encounter their specific antigens?
Recirculate the secondary lymphoid tissue until they meant their specific antigens
What receptors do double negative T cells express?
CD3
TCR
CD28
What are double positive T cells?
T cells that express both CD4 and CD8 on their surface
Formed when they enter the thymus
How do T cells become single positive?
Through selection processes in the maturation of T cells in the thymus
Dendritic cells express MHC bound to antigen
Positive selection
What do cytotoxic T cells do?
Kills infected and transformed cells
Virally infected
Intracellular bacteria
Cancer cells
What do T helper cells do?
Provides help to other cells like Macrophages and B cells
By secreting cytokines that recruit inflammatory cells
Which cells produce cytokines?
Most cells of the immune system
How do Cytotoxic T cells recognise antigens compared to T helper cells
Cytotoxic T cells recognise antigens that have invaded APCs
Helper T cells recognise freee floating antigens that APCs bind to in order to present them
What happens if costimulatory molecules are not involved in activation of T cells?
Without the costimulatory molecules you get cell anergy
What happens following activation of T cells?
Proliferation and make
Cells like itself - effector T cells
Memory cells - non-effector T cells
What do cytokines do?
Signal through paracrine, endocrine and autocrine pathways
How do cytokines cause cellular changes?
Signal through cytokine receptors on CSM
Trigger complex intracellular signalling cascade
End up with transcription of different genes inside cells
Produces different effector proteins or inactivation of cells
What are chemokines?
Family of chemotactic cytokines released by infected cells that recruit inflammatory cells to site of infection
