What can you use to study damage to the immune system?
| Flow cytometers are also found
in many hospitals for clinical uses. They are used to measure
blood cell counts in patients infected with HIV and in patients
with leukemia, cancer of the white blood cells. In the case
of HIV-infected patients, the flow cytometer is used to count
CD4+ T-cells, the cells that are killed by HIV. The response
of leukemia patients to chemotherapy is monitored
by counting the different types of leukocytes. |
The flow cytometer (sy-TAH-mee-ter; cyto:
cell, meter: measure) is a unique instrument used in both
health care and research laboratories. Cytometry refers
to the measurement of the physical and chemical characteristics
of cells. Flow cytometry is the process in which measurements
are made while cells in a liquid suspension are forced to flow one
at a time through a measuring device.
Each of the types of immune system cells has a unique combination
of size, shape, DNA content, and proteins. Using these measurements,
scientists can use the flow cytometer to determine the amount of
each type of cell in a blood or tissue sample.
For example, a flow cytometer can be used to count the number and
type of leukocytes (white blood cells) in a person’s blood.
In a healthy person, granulocytes make up 50-60% of the total leukocytes
and lymphocytes are about 30-40%. A person whose white blood cell
counts differ from these numbers may be experiencing a problem with
their immune system.
Doctors and scientists used to count cells with a microscope which
is a very slow process. However, the invention of the flow cytometer
allowed them to count thousands of cells in minutes and obtain much
more detailed information.
But what exactly does the flow cytometer do?
|
Measures the physical and chemical characteristics of cells.
It can measure a cell’s diameter, volume, surface area,
and granularity. |
Identifies and quantifies different types of cells by their
surface proteins.
|
Determines a cell’s internal structure, including
its DNA content, enzymes, and proteins. |
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