Phaseolus vulgaris agglutinin is the name ascribed to a family
of lectins, each of which consists of four subunits. There are
two different types of subunits. One appears to be involved
primarily in red cell agglutination and has been designated the
“E” subunit (for erythroagglutinin). The other type is involved
in lymphocyte agglutination and mitogenic activity and has
been termed the “L” subunit (for leucoagglutinin).
These subunits combine to produce five isolectins.
One of these isolectins has four “E” subunits and is designated
PHA-E. PHA-E possesses strong hemagglutinating activity
but is a poor mitogen. PHA-L, with four “L” type subunits,
does not agglutinate red cells but is a potent mitogen. The
other three isolectins, designated E3L1, E2L2, and E1L3, have
erythroagglutinating and mitogenic activities proportional to
the number of respective “E” or “L” subunits. We have termed
the mixture of the five isolectins PHA (E+L).
PHA-L has been found to be an excellent, specific marker for
use in anterograde neuronal tracing.
After iontophoretic injection of PHA-L, the approximate rate of anterograde transport
is about 4-6 mm/day, with survival periods of
over 18 days having been observed. Once
transported, the PHA-L is best visualized for light microscopy with antibody to the lectin,
followed by the appropriate VECTASTAIN® Elite
ABC kit and DAB. Fluorescent staining
can also be used for a faster staining procedure. A complete applications protocol is available upon request.
Elution: 100 mM acetic acid
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