16th Page Flashcards
2 categories of laboratory methods for complement detection
1) Measurement of components as antigens in serum
2) Measurement of functional activity
What methods are most frequently used to measure individual complement components?
Radial Immunodiffusion and Nephelometry
can also be used to measure individual complement components (CH50)
ELISA
What is the Hemolytic Titration assay used for?
It is the most commonly used assay for the classical pathway
measuring the amount of patient serum required to lyse 50% of a standardized concentration of antibody-sensitized sheep erythrocytes.
Hemolytic Titration assay
Hemolytic Titration assay is also known as
CH50 Assay
Titer expressed in the Hemolytic Titration assay?
The titer is expressed in CH50 units
which is the reciprocal of the dilution that is able to lyse 50% of the sensitized cells.
What is the purpose of adding magnesium chloride and EGTA in the buffer?
These substances chelate calcium, which blocks classical pathway activation.
EGTA stands for
ethylene glycol tetraacetic acid
What can decreased levels of complement components or activity indicate?
They may be caused by decreased production, consumption, or in vitro consumption.
What are the specimen collection requirements for complement testing?
Blood should be collected in a clot tube with no serum separator, spun down, and the serum should be placed on dry ice if not tested within 1-2 hours.
56 degree for 30 mins
What is the indicator used in the Complement Fixation Test?
Sheep RBC coated with anti-sheep antibody / Amboceptor / Hemolysin.
What does a positive result in the Complement Fixation Test indicate?
No hemolysis
What does a negative result in the Complement Fixation Test indicate?
With hemolysis
What is the procedure for centrifugation in the context of complement testing?
Centrifuge more than once, and after centrifugation, heat at 56°C for 30 minutes.
What are cytokines?
chemical messengers that regulate the immune system
both innate immunity and the adaptive response to infection
Cytokines
Cytokines
small proteins produced by several different types of cells.
What are lymphokines?
produced by T cells.
What are monokines?
produced by monocytes/macrophages.
Cytokines are NOT produced by B cells
TRUE
What induces the production of cytokines?
In response to the binding of stimuli, such as bacterial lipopolysaccharides or flagellin, to specific cell receptors.
Or recognition of foreign antigens
What are the effects of cytokines?
regulate growth, differentiation, and gene expression by many different cell types, including leukocytes.
What is autocrine activity?
stimulation affecting the same cell that secreted the cytokine.
