Adaptive immune responses Flashcards
(T/F) B cells produce antibodies specific to pathogens (protection against infection), while T cells promote killing of infected cells (eradication of established infection)!
True!
B cells and T cells have receptors that recognize foreign _______.
These cells are also known as ________ - major effector cells of the adaptive response.
antigens
lymphocytes
What are dendritic cells?
Dendritic cells bridge the INNATE and ADAPTIVE response. They are phagocytic cells and ‘present’ antigen to T cells in order to initiate the adaptive response.
They are called ‘ANTIGEN PRESENTING CELLS (APCs)’.
(T/F) Dendritic cells come from the lymphoid progenitor, while the B and T cells come from the myeloid progenitor. Both lymphoid and myeloid come from the pluripotent hematopoietic stem cell.
False!
Dendritic cells come from the myeloid progenitor, while the B and T cells come from the lymphoid progenitor. Both lymphoid and myeloid come from the pluripotent hematopoietic stem cell.
(T/F) All lymphocytes (B/T cells) have the same antigen receptor.
False!
Each lymphocyte has a UNIQUE ANTIGEN RECEPTOR, meaning that they each recognize a specific antigen.
What happens when an antigen interacts with its corresponding antigen receptor?
Interaction of antigen with its corresponding antigen receptor initiates SIGNALING CASCADES within the lymphocyte, which promotes CELL PROLIFERATION, DIFFERENTIATION, and ACTIVATION of effector functions of the lymphocyte in order to defend against the foreign invader.
1) Each lymphoid progenitor gives rise to a large number of lymphocytes, each bearing a _______ antigen receptor.
2) Lymphocytes with receptors that bind ____ antigens are eliminated before they become fully mature, ensuring _______ to ___ antigens.
3) When a foreign antigen interacts with the receptor on a ______ lymphocyte, that cell is activated and starts to divide. It gives rise to a clone of ________ _____, all of whose receptors bind the _____ antigen.
4) Antigen specificity is thus maintained as the progeny proliferates and differentiates into _______ cells. Antigen is eliminated by these cells, some lymphocytes are retained to mediate ___________ _______.
1) Distinct
2) Self; tolerance; self
3) Mature; identical progeny; same
4) Effector; immunological memory
What is required for adaptive immune responses to be initiated?
It requires antigens to be ‘presented’ by antigen presenting cells (APCs) to T cells!
Briefly describe how dendritic cells work.
During innate response (early on during infection), dendritic cell is in its immature step, where it is highly phagocytic (wants to engulf foreign particles).
Once it engulfs, it breaks the foreign particles into small peptides which are presented/ loaded onto MHC cells!
MHC cells present these peptides to T cells!
(T/F) Dendritic cells have PRRs and when bound to MAMPs, it leads to cytokine secretion. Nf-kb activation promotes the maturation of the dendritic cell.
True!
What are the morphological changes seen in a mature dendritic cell?
1) No longer phagocytic
2) Generates long filament like structures, which serve as display area for the MHC peptide complexes
Along with Nf-kb activation, _______ of the immature dendritic cell to _____ _____ is also required for maturation.
migration; lymph node
1) What is a Naive T cell?
2) What leads to T cell activation and differentiation?
3) Aside from the answer to number 2, what else contributes to T cell activation and differentiation?
1) A naive T cell is a cell that has not encountered its specific antigen.
2) T cell Receptor (TCR)-MHC:peptide engagement leads to T cell activation & differentiation.
3) Cytokines (secreted by the dendritic cell) & costimulatory molecules also contribute to T cell activation & differentiation.
Antigen peptides found in the _______ of the APC bind to MHC class I molecules. Peptide-MHC class I complexes are recognized by antigen receptors on the _______ T cell.
Antigen peptides found in the _______ of the APC bind to MHC class II molecules. Peptide-MHC class II complexes are recognized by antigen receptors on the _______ T cell.
Cytosol; CD8+ T cell
Intracellular vesicles; CD4+ T cell
(T/F) While viruses generally use the Class I MHC pathway, bacteria/fungi use the Class II MHC pathway.
True!
