Immunology Flashcards
What cytokines are secreted by TH1 cells?
IL-2, INF-g
What cytokines are secreted by TH2 cells?
IL-4, IL-5, IL-10, IL-13
What is a granuloma, what mediates its development?
Defined by the presence of a collection of epithelioid histiocytes. May also contain giant cells (multinucleated cells formed by the fusion of multiple epithelioid histiocytes; may also be surrounded by a ring of lymphocytes.
INF-g, secreted by TH1 cells, is the mediator of macrophage transformation into epithelioid histiocytes that occurs in granulomatous inflammation.
What test can be used to determine the presence of antibodies in a patient’s serum?
ELISA
What test detects the presence/levels of RNA in a cell?
Northern blot
What test is used to detect presence/level of DNA?
Southern blot
What immune cells exit the blood/leave circulation early in infection? What molecules mediate this process?
Neutrophils
IL-8, C5a, LTB4, bacterial products (e.g.; f-met peptides)
What type of hypersensitivity does the tuberculin skin test demonstrate?
Type IV Hypersensitivity– a cell-mediated immune response involving CD4+ TH1 cells activating and attracting macrophages to the area. The most important cytokine stimulating this response is INF-g that is secreted by the TH1 cells to activate the macrophages.
The TB skin test is a classic demonstration of the function of the cell-mediated arm of the immune response (as opposed to the humoral immune response).
What is the Arthus Reaction?
This is an example of Type III Hypersensitivity–disease caused by antigen-antibody immune complexes.
The Arthus reaction is induced by subcutaneous administration of a protein antigen to a previously immunized individual. It results in the formation of immune complexes at the site of antigen injection, and a local vasculitis.
Diapedesis
the passage of blood cells through the intact walls of capillaries, typically accompanying inflammation
Which immune system cells are always the first responders to any injury?
Neutrophils
After 48 hours, would neutrophils be the predominant cell at the site of infection/injury?
No
What is the predominant cell at the site of infection/injury after 48 hours?
Macrophages
What are LAK cells?
These are NK cells that have been activated by IL-2. They are considered to be super-activated NK cells.
What is the role of NK cells?
They function in killing altered self cells, such as tumor cells or virus-infected cells. They participate in ADCC (antibody-dependent cellular cytotoxicity)
On which cells is CD19 found?
B cells
On which cells is CD16 found? what is its function?
NK cells, macrophages, mast cells
It is an Fc receptor; functions in ADCC
Where is CD3 found? What is its purpose?
On T cells and thymocytes.
It is part of the TCR (g,d,e,z subunits) and is involved in signal transduction by the TCR
What would happen if a patient’s cells lacked MHCII expression?
The patient would lack CD4+ t cells. During positive selection in the cortex of the thymus, only those cells that can recognize antigen presented on MHC proteins will be rescued from cell death. Without MHC class II proteins, no CD4+ cells will develop/be rescued. This patient will still be able to make CD8+ cells, but because Th cells are important in virtually all immune responses (humoral and cell-mediated, for example), the lack of CD4+ cells will affect the patient’s ability to respond to intra- and extracellular pathogens.
