The lectin Phaseolus vulgaris leucoagglutinin
(PHA-L) has come into wide use as an anterograde
neuroanatomical tracer. The ability of this
lectin to fill entire neurons and remain in place
over long periods suggested it might be an ideal
marker for donor cells to be grafted into hosts
for long survival periods. We have used the lectin
PHA-L to mark fetal rat olfactory bulb (OB)
cells prior to grafting into host rat OBs. Hosts
were sacrificed at various times up to 9 weeks after
grafting, and tissue was immunohistochemically
processed for PHA reactivity. After 2 and 4
weeks survival, sparse patterns of labeled cells
were observed within the host OBs. However, after
9 weeks survival, few if any labeled cells were
visible within host tissue. We conclude that
PHA-L may be a less than satisfactory marker
for fetal rat cells (other than astrocytes) which
are to be identified in host tissue after a period of
several weeks