Protein transfer of glycosyl-phosphatidylinositol (GPI)-modified murine B7-1 and B7-2 costimulators.

Publication/Presentation Date

9-1-1999

Abstract

The feasibility of using protein transfer as a means for enhancing the immunogenicity of murine tumor cells was evaluated. Glycosyl-phosphatidylinositol (GPI)-modified variants of the murine costimulators B7-1 (CD80) and B7-2 (CD86), designated B7-1.GPI and B7-2.GPI, respectively, were immunoaffinity-purified from CHO-K1 cells transfected with glutamine synthetase amplification/expression constructs encoding each of these chimeric proteins. The proteins, once purified in detergent-depleted pseudomicelles, were exogenously incorporated into the membranes of several different murine tumor lines (EL-4, SMUCC-1, BW5147.3, P815, Ag104A, and EMT6). Successful membrane painting with the B7.GPI proteins was documented by immunofluorescence and flow cytometry, and membrane integration was verified by demonstrating that the reincorporated proteins were phosphatidylinositol-phospholipase C-sensitive, glycosyl-phosphatidylinositol-phospholipase D-resistant, and refractory to removal with dimyristylphosphatidylcholine vesicles. Significantly, B7-1.GPI and B7-2.GPI could be together copainted onto EL-4 cell surfaces with no interference observed between the two. A standard in vitro proliferation assay was used to show that both of the B7.GPI proteins retained costimulator function after membrane reincorporation. These findings further validate the therapeutic potential of protein-transferred costimulator.GPIs and pave the way for their combinatorial use in animal tumor models.

Volume

22

Issue

5

First Page

390

Last Page

400

ISSN

1524-9557

Disciplines

Business Administration, Management, and Operations | Health and Medical Administration | Management Sciences and Quantitative Methods

PubMedID

10546154

Department(s)

Administration and Leadership

Document Type

Article

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