In situ expression of @entity3646 ( @entity3646 ) receptors in @entity1 @entity1313 and cytotoxicity of a recombinant @entity3646 cytotoxin in primary XXXX cell cultures.

@entity1 @entity9597 @entity1313 @entity11 @entity816 @entity3646 @entity463
We have reported that @entity1 @entity11 cell lines express high levels of plasma membrane @entity9597 ( @entity9597 ). We have also reported that biopsy/surgical samples or primary explant cell cultures from @entity1313 express mRNA and protein for the @entity9597 chain, a primary @entity3646 -binding protein. However, whether @entity9597 are expressed in @entity1313 in situ has not been resolved. In addition, expression of @entity9597 on the cell surface of various normal brain tissues is not known. We examined the expression of @entity9597 by using a monoclonal antibody to the @entity9597 chain (also known as @entity9597 beta) in surgical/biopsy samples of @entity1313 tissues by immunohistochemistry. Our data indicate that 15 of 18 @entity463 obtained from two different institutions and 12 other @entity1313 samples are moderately to intensely positive for @entity9597 . In contrast, although @entity9597 mRNA was expressed, no @entity9597 protein was detectable in two adult and one pediatric brain tissue specimens. In addition, a commercially available @entity1 neural tissue grid containing fixed tissues from various areas of brain showed no positive staining for the @entity9597 chain. @entity9597 expression was also demonstrated on @entity816 grades I, II, and III. Because @entity3646 cytotoxin comprised of a circularly permutated @entity3646 and a mutated form of Pseudomonas exotoxin [IL4(38-37)-PE38KDEL] is cytotoxic to @entity9597 -expressing cells, we tested whether primary GBM explant cell cultures are sensitive to @entity3646 cytotoxin. Our data indicate that 13 of 15 GBM cell cultures were 25-74 times more sensitive to @entity3646 cytotoxin compared with normal @entity1 astrocytes or the NT2 neuronal cell line. These observations indicate that @entity1 @entity1313 in situ overexpress @entity9597 compared with normal brain tissues, thus confirming our previous conclusions that @entity9597 in @entity1313 may serve as an attractive target for anticancer therapy.
