T & B-Cells Dev. Flashcards
Thymocytes
immature T-Cells
Hematopoietic stem cell
blood stem cell, immature cell that can develop into any blood cell
AIRE
Auto-Immune REgulator, a transcription factor responsible for the clonal detection of self-antigen-specific T-cells
T-cell
Cells in possession of a T-cell receptor (TCR)
Name the three types of mature naïve T-cell
alpha-beta CD4+
alpha-beta CD8+
dy T-cells
Mature naïve T-cell
ready to response, although not done so, not yet an effector cell
Stages of T-cell development
EARLY STAGES (TCR independent):
i) Commitment to the T cell lineage
ii) Initiation of TCR gene rearrangements
iii) Selection and expansion of cells that have successfully rearranged their β TCR genes
LATE STAGES (TCR dependent):
i) Positive selection for self-MHC recognition (TCR binding = survival) ii) Negative selection for self-antigens (TCR binding = death)
iii) Commitment to CD4+ or CD8+ lineages
B-1 B Cells
~ originate during foetal development, where haematopoesis occurs in the foetal liver
~ self-regenerating minor population of B cells
B-2 B Cells
~ originate by haematopoesis in the bone marrow
~ major type
~ can be divided into follicular B cells and marginal zone B cells
Where are Marginal zone B cells found?
spleen
Where are follicular B cells found?
follicles of lymph nodes
Professional Antigen-Presenting Cells
~ Dendritic cells (best at activating naïve T-cells)
~ Macrophages
~ B Lymphocyte
ALL activate effector and memory cells
Superantigens
spontaneously bind to Vbeta regions of TCRs and the alpha chains of MHC class II e.g. exotoxins --> can cause massive polyclonal T-cell activation
Polyclonal T-cell activation
activation of many T-cells of different specificities = diversion from the exotoxin-producing pathogen
Anergy
absence of the normal immune response
