Adaptive Immunity 1 Flashcards
(23 cards)
What adaptive immune response consists of?
Cell-mediated responses and antibody responses
What is the role of T cells in adaptive immunity??
T cells drive cell-mediated immunity, it involves the activation of macrophages, natural killer (NK) cells.
* B cells produce antibodies driving humoral
immunity
What is the role of B cells in adaptive immunity??
B cells produce antibodies driving humoral
immunity
What is immunological memory?
Each pathogen remembered by a signature T cells and/ or B cell receptor
What are the three main receptors in adaptive immunity?
-T cell Receptor
-B cell Receptor
-Major Histocompatibility Complex (MHC)
Where T cells derived from and mature in?
They are derived from the bone marrow they mature in the Thymus (hence the ‘T’)
What cells give rise to cellular immunity?
T cells
Name different subset of T cells?
- T helper cells (CD4+) function to help support other immune cells to fight threats
- Cytotoxic T cells (CD8+) destroy our own cells which have become infected (usually virus-related)
- Regulatory T cells (Tregs): regulate or suppress other cells in the immune system
Mention T cell receptors
The T cells receptors are comprised of
- Constant region
- Variable region
Three genetic segments confer diversity to variable region:
- (V) Variable - (Alpha and Beta chains)
- (D) Diversity - (Beta chains only)
- (J) Joining - (Alpha and Beta chains)
What are the classes of T cell receptors:
- Alpha & Beta chains - Majority of T cells have this configuration
- Delta & Gamma chains - 5% of T cell population - role unknown
Pre-thymic T cells educated in Thymus via two types of selection:
- Positive selection - No recognition → Induced apoptosis
- Negative selection - Recognition of self antigen → Induced apoptosis
Process of thymic education is facilitated by interactions with?
T cell interact with Thymic cortical epithelial cells
What type of immunity provides immunological memory?
Adaptive immunity
How genes are re-arranged ?
Somatic recombination
Hoe T cells get activated?
From antigen presentation by DCs
Where T cells priming occurs and what it results?
In the lymph nodes and results in differentiation into subsets
T cell priming
- Signal 1 - Recognition of antigen presented by MHC on dendritic cells: T cells recognize antigen presented by dendritic cells via T cell receptor (TCR) binding to the antigen-MHC complex.
( naïve T cell activation (MHC-TCR) ) - Signal 2 - Co-stimulation: T cells require a second signal to become fully activated, which is delivered by co-stimulatory molecules on dendritic cells, such as CD80 and CD86, binding to CD28 on T cells.
( preventing T cell anergy ) - Signal 3 - Cytokine stimulation: T cells receive cytokine stimulation from dendritic cells, which helps determine their initial differentiation into effector or memory cells.
( cytokine response drives differentiation )
TH2 cells roles?
-Main role in supporting humoral responses and allergic reactions
-Source of cytokines such as interleukin-4, 5 and 6 (IL-4, IL-5 and IL-6) which instruct B cells to produce antibodies
Regulatory T cells roles?
Main role is to function in immune suppression by releasing inhibitory cytokines (e.g., interleukin-10,[IL-10]) which
inhibit T cell and DCs activation
Cytotoxic T cells roles?
Activation arises from interactions between MHCI and TCR
Induce host cells to undergo apoptosis (programmed cell death)
Produces enzymes such as granzyme/ perforin
What granzyme/perforin does when they produced?
-Perforins: form pores in the plasma membrane
-Granzymes: enter the cell and break down proteins, lysing the cells
