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Figure 4.18 Photomicrograph showing the detection of cytoplasmic
antigens following the production of a colored marker using enzyme
immunohistochemistry.
Figure 4.17 (A) Schematic showing the detection of cellular antigens, in this case CD3, by immunofluorescence as described in the text. (B) Computer
generated image showing the distribution of membrane antigens as detected by immunofluorescence.
CD3
Mouse antiCD3
A)
Fluorescein-
conjugated
antimouse IgG
Represents the
fluorochrome,
fluorescein
B)
Protein Rolein vivo Found on
Surface immunoglobulin epitope receptor B lymphocytes
CD3 signal transduction following
binding of T cell
receptor to epitope
all mature T lymphocytes
CD4 coreceptor molecule helper T lymphocytes (TH)
CD8 coreceptor molecule cytotoxic T cell precursors (TC) and
cytotoxic T lymphocytes (CTL)
Table 4.4Marker proteins for T and B lymphocytes
Labels other than fluorochromes are available, which
allow the production of permanent preparations
and the use of an ordinary light microscope. For
example, antibodies labeled with an enzyme, such
as horseradish peroxidase or alkaline phosphatase
can be located by their ability to convert a colorless
substrate into an insoluble colored compound
that can be seen when the cells are examined
microscopically. This technique is called enzyme
immunohistochemistry (Figure 4.18).
BOX 4.3 Distinguishing T and B lymphocytes