Summary A trophoblast cell surface antigen has been characterised by a monoclonal antibody (mAb) 5T4, raised following immunisation with solubilised wheat germ agglutinin binding glycoproteins from human syncytiotrophoblast plasma membrane (StMPM). The expression of the 72 kDa glycoprotein was assessed on cryostat sections of a range of neoplastic and non-neoplastic tissues, using an avidin-biotin immunoperoxidase technique. In products of conception, intense reactions were noted with villous syncytiotrophoblast membrane in normal early and term placenta, with weaker positivity of placental site trophoblast. Most normal or non-neoplastic tissues were negative, including liver, kidney, spleen, small intestine, ovary Specifically, sections were washed in two changes of tris buffered saline (TBS) pH 7.6 and then covered with 10% normal horse serum in TBS for 20 min. After draining, the slides were incubated with neat culture supernatant for 30 min in a moist chamber. Following three washes in TBS (5 min each), biotinylated anti-mouse Ig (Vector Laboratories) diluted 1/250 in TBS containing 10% normal human serum was applied. After 30 min incubation in the moist chamber, the slides were washed three times and incubated with the avidin-biotin peroxidase complexes reagent (Vector Laboratories) for 50 min. After three washes in TBS, peroxidase was visualised using a freshly prepared and filtered solution of diaminobenzidine tetrahydrochloride (DAB-Sigma) in TBS containing 0.03% hydrogen peroxide (6 min). Sections were washed in tap water and counterstained in Coles' haematoxylin, dehydrated, cleared and mounted (Ralmount-R.A. Lamb). The immunohistochemical results were interpreted with reference to a set of controls run in parallel with each test. These included sections treated with DAB only to show endogenous peroxidase, omission of the primary antibody and replacement of the primary antibody with one of the same class but of unrelated specificity. Reactivity of mAb 5T4 with fixed and paraffin wax embedded sections of term placental trophoblast was also assessed by immunoperoxidase. 5T4 mAb reactivity was assessed by P.J.S. and G.M.B. and the intensity of staining was scored on an arbitrary scale ( + to + + + ). Very weak or equivocal reactions were scored + /-.Flow cytometric analyses of human bone marrow cells labelled in PBS, 1% BSA 0. 1% azide with 5T4 mAb followed by 1/20 rabbit anti-mouse Ig-FITC (Serotec, Bicester, UK) was performed on a Becton-Dickenson FACS analyser. The purified mAb 5T4 at 10 ig ml-' was tested for interference with the growth of human pluripotential haematopoietic colonies as described by Welte et al. (1985). RadioimmunoassaySyncytiotrophoblast microvillous plasma membranes (StMPM) were prepared as previously described (Hole &
Solid tumors have a heterogeneous pathophysiology, which directly affects antibody-targeted therapies. Here, we consider the influence of selected tumor parameters on radioimmunotherapy, by comparing the gross biodistribution, microdistribution, and therapeutic efficacy of either radiolabeled or fluorescently labeled antibodies (A5B7 anti-carcinoembryonic antigen antibody and a nonspecific control) after i.v. injection in two contrasting human colorectal xenografts in MF1 nude mice. The LS174T is moderately/poorly differentiated, whereas SW1222 has a well-differentiated glandular structure. Biodistribution studies (1.8 MBq 131 I-labeled A5B7, four mice per group) showed similar gross tumor uptake at 48 h in the two models (25.1% and 24.0% injected dose per gram, respectively). However, in therapy studies (six mice per group), LS174T required a 3-fold increase in dose (18 versus 6 MBq) to equal SW1222 growth inhibition (f55 versus f60 days, respectively). To investigate the basis of this discrepancy, highresolution multifluorescence microscopy was used to study antibody localization in relation to tumor parameters (5 min, 1 and 24 h, four mice per time point). Three-dimensional microvascular corrosion casting and transmission electron microscopy showed further structural differences between xenografts. Vascular supply, overall antigen distribution, and tumor structure varied greatly between models, and were principally responsible for major differences in antibody localization and subsequent therapeutic efficacy. The study shows that multiparameter, high-resolution imaging of both therapeutic and tumor microenvironment is required to comprehend complex antibody-tumor interactions, and to determine which tumor regions are being successfully treated. This will inform the design of optimized clinical trials of single and combined agents, and aid individual patient selection for antibody-targeted therapies. [Cancer Res 2007;67(24):11896-905]
In three patients in whom a diagnosis of gestational trophoblastic tumor was possible on the basis of pathology and elevated levels of serum human chorionic gonadotrophin, locus‐specific minisatellite probes were used to identify restriction fragment length polymorphisms (RFLP) in DNA from the tumor, the patient, and her partner. On the basis of results from these studies, one tumor, originally diagnosed as a germ cell tumor, was reclassified as a gestational choriocarcinoma, whereas a second tumor, diagnosed as gestational choriocarcinoma, was shown to be of nongestational origin. In the third case, a diagnosis of gestational trophoblastic tumor was confirmed, but in this case the androgenetic origin of the tumor indicated that it was derived, not from the antecedent term pregnancy, but from a previous pregnancy with hydatidiform mole. This study clearly demonstrates the value of DNA analysis in the classification of tumors with trophoblastic differentiation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.