Toxoplasma gondii
invades and proliferates in human umbilical vein endothelial cells where
it resides in a parasitophorous vacuole. In order to analyze which components
of the endothelial cell plasma membrane are internalized and become part
of the parasitophorous vacuole membrane, the culture of endothelial cells
was labeled with cationized ferritin or UEA I lectin or anti Class I human
leukocytte antigen (HLA) before or after infection with
T. gondiii
. The results showed no cationized ferritin and UEA I lectin in any parasitophorous
vacuole membrane, however, the Class I HLA molecule labeling was observed
in some endocytic vacuoles containing parasite until 1 h of interaction
with
T. gondiii
. After 24 h parasite-host cell interaction, the labeling was absent on
the vacuolar membrane, but presents only in small vesicles near parasitophorous
vacuole. These results suggest the anionic site and fucose residues are
excluded at the time of parasitophorous vacuole formation while Class I
HLA molecules are present only on a minority of Toxoplasma-containig vacuoles.
