T2 Lecture 5 Flashcards
Explain the process by which leukocytes are recruited into tissues.
Resident macrophages recognize PAMPs and DAMPs respond by producing cytokines, such as IL-1 and TNF.
What is “activating the endothelium”?
It is the stimulation of the endothelium at site of infection by IL-1 and TNF-alpha to express adhesion molecules, which bind leukocytes to the endothelium.
What are some chemoattractants involved in chemotaxis?
Chemokines and C5a
What are some of the effector functions of neutrophils and macrophages?
Phagocytosis, production of cytokines, and presentation of antigens to T cells (Macrophage only)
What 3 things are used in bacterial infection?
Neutrophils, Macrophages, and Complements
Why do phagocytes make phagolysosomes?
In order to use enzymes and toxic molecules to kill pathogens safely.
Describe the process of innate immunity vs. viruses
- Virus infects cell
- Resident macrophages and mast cells respond by releasing mediators that increase permeability of blood vessels.
- Allows NK cells to enter bloodstream.
- NK cells release chemical mediators to kill infected cells via apoptosis.
Describe the process of innate immunity vs. parasites
- Parasite infects host
- Macrophages and mast cells release chemical mediators that increase permeability of blood vessels.
- Eosinophils, mast cells, and some basophils enter tissue from the bloodstream.
- Eosinophil granules release toxic chemicals to kill the parasite.
Describe the process of innate to adaptive immunity
- Dendritic cells gather antigen from tissues
- Dendritic cells go through lymphatic vessels to peripheral lymphoid organs, where they present antigens to naive T cells.
- Pathogen-specific T cells are activated.
- Effector T helper cells and effector CD8 cytotoxic cells are made.
- T helper cells costimulate B-cells into plasma cells to release antibodies.
- CD8 T cells and antibodies fight the infection.
What are the types of adaptive immunity?
Humoral adaptive immunity modulated by B-cells.
Cell-mediated adaptive immunity, which is carried out by T cells.
What is the difference between the two types of cell-mediated adaptive immunity?
T helper cells are when there are intracellular microbes that cannot be killed by macrophages, such as bacteria and protozoa. T helper cells enhance phagocytosis.
CD8 T-cells are when there are intracelullar microbes like viruses. Cytotoxic T cells cause apoptosis.
Why do B cells require Th2 cells?
B cells on their own can recognize antigens, but need stimulation from a Th2 cell to become fully activated, which is known as costimulation. This involves a receptor-ligand interaction.
What is the proliferation of B cells known as?
Clonal expansion, occurring after activation/costimulation.
How do B cells differentiate with their antibodies?
They do isotype switching, by changing their heavy chain antibody isotypes.
What is affinity maturation?
It is the selection process that helps B cells create a stronger bond between their receptor and antigen.
What is the first antibody made by any plasma cell?
IgM
What happens to B cells that do not become plasma cells?
They become memory cells to fight off the infection faster in the future.
Describe the makeup of an antibody.
Antibodies are made of 4 polypeptide chains with at least 2 identical antigen binding sites on top.
They have a pair of identical light chains and heavy chains, which is the Fab fragment of the antibody. It is the Y ending and is variable.
What is the constant region of the antibody?
It is the sequences of amino acids that make up the bottom core of the antibody. It determines the class/end function of the Ig antibody.
What is the complementary antigen to a Fab fragment?
epitope
What is the most common Ig?
IgG
Which Ig is needed for B-cell maturation?
IgD
Which Ig activates complements?
IgM and sometimes IgG
Which Ig is found in bodily secretions?
IgA
Which Ig gives a newborn passive immunity?
IgG
Which Ig can cross the placenta?
IgG