B Elements of immune system Flashcards
What is an antigen
From antibody generation, an antigen is something that stimulates an immune response
What are some examples of structures that can be antigens?
Proteins, polysaccharides, lipids, but also metals such as nickel
What is immune tolerance?
Control mechanisms to stop the immune system from reacting towards the hosts own tissue
What are the main differences between innate and adaptive immune system?
Fast, non-specific, no memory vs slow, highly specific, memory
What are the precursor to all immune cells?
Hemopoietic stem cells
Which lineages of immune cells is there?
Granulocyte progenitor and lymphoid progenitor
Which are the granulocytes?
Eosinophils, basophils, neutrophils
Where do production of all immune cells begin?
Bone marrow
Bone marrow
Production of stem cells. B lymphocyte maturation
Thymus
T-lymphocyte maturation
Naïve cells
Mature cells that are not yet activated by contact with antigen
Effector cells
Activated lymphocytes
Basic structure of lymph node
Cortex, germinal centers, medulla
Cortex (lymph node)
Aggregates of B-lymphocytes in follicles
Germinal centers
Activated B-lymphocytes
Paracortex
Surrounds the cortex, T-cells are here
Medulla
Macrophages and plasma cells
Plasma cells
Fully differentiated B-lymphocytes, have no BCR but only produce antibodies
Name the immune cells of the innate immune system
Granulocytes (neutrophil, basophil, eosinophil), mast cells, compliment proteins, monocytes/macrophages, dendritic cells, NK cells
Name the immune cells of the adaptive immune system
B-lymphocytes / plasma cells, T-lymphocytes (CD4+ T-cells/Helper T-cell & CD8+ T-cells / cytotoxic T-cell), NK cells
Antigen presenting cells
Macrophages, dendritic cells, B-lymphocytes , (t-lymphocyte?)
Basics of T-cell receptor (TCR)
Only recognize epitope from partially degraded proteins coupled to a MHC. One alpha chain and one beta chain. Also need a co-stimulatory signal from either CD4 or CD8, which also dictate which MHC class they can interact with
Basics of B-cell receptor (BCR)
What later becomes the antibodies; when a BCR it has a transmembrane portion making it stick to the surface of B-lymphocytes. Two heavy chains and two light chains. One constant region and one variable; variable with CDRs decide which epitope it can bind to. Different amount of Fc depending on which subset.
Humoral immunity
Antibody mediated immunity. Responds directly to microbes. B-lymphocytes responsible
Cell-mediated immunity
Activation of T-lymphocytes by a cell from the innate immune system, by interacting with MHC class I or II
How many types of antibodies are there in humans?
Five
Basic structure of an antibody
2 heavy chains, 2 light chains. Variable regions which are the ones that bind to the epitope and vary. Constant regions are the same in the same type of antibody (i.e IgG all have the same c-region but different v-regions depending on target). Paratope that can bind to epitope
Epitope
Small part of an antigen that the antibody recognize and bind to. Several different antibodies can recognize different epitopes on the same antigen.
PRRs
Expressed by macrophages, neutrophils and DCs, recognize different conserved structures in pathogens known as PAMPs
Cytokines
Proteins secreted from immune cells to communicate with other immune cells with the correct receptor.
Chemokines
Attracts immune cells with correct receptor; move towards place with highest concentration of chemokine.
Describe how an inflammation works.
Bacteria enter wound - macrophages recognize PAMPs with their PRRs
Macrophages release cytokines and chemokines which causes vasodilation and increased adhesive properties for other immune cells and opens up epithelium slightly, making it possible to move into the tissue.
Immune cells are attracted by chemokines and move to the area with bacteria, start eating them
