Abstract
An ecotropic virus was chemically modified in order to determine whether its target cell specificity could be altered. We hypothesized that chemical coupling of galactose residues to a virus might permit specific infection of hepatocytes mediated by asialoglycoprotein receptors unique to these cells. To test this hypothesis, we took advantage of the fact that: 1) artificial asialoglycoproteins can be created by chemical coupling of lactose to proteins; and 2) viruses that are ecotropic have a narrow species specificity. An ecotropic, rodent-specific, replication-defective murine leukemia virus containing the gene for beta-galactosidase was chemically modified with lactose to contain 5.9 mumol of lactose per mg of viral RNA. Modified and unmodified viruses were incubated for 5 days with HepG2, a human hepatoma line that possesses asialoglycoprotein receptors, and SK Hep1, a human cell line that does not. As expected from the ecotropism, unmodified virus did not produce beta-galactosidase activity in either cell type. Modified virus did not produce beta-galactosidase activity in SK Hep1 cells. However, modified virus did produce beta-galactosidase activity, 71.2 units/mg of cell protein, in the human receptor (+) HepG2 cells. Interestingly, modification of the virus also resulted in decreased enzyme activity in previously susceptible host rodent cells. Competition with modified virus by an excess of an asialoglycoprotein completely prevented development of enzymatic activity in HepG2 cells. Histochemical treatment of cells with 5-bromo-4-chloro-3-indoyl beta-D-galactoside to detect in situ beta-galactosidase activity demonstrated that only HepG2 cells treated with modified virus were positive and that 36% of these cells were stained after 5 days. These data indicate that chemical modification of a virus can result in a redirection of the infectivity of the virus toward hepatocyte-derived cells mediated by the presence of asialoglycoprotein receptors.
Highlights
Virus ognized and bound by cellular receptors
Results in Redirection ofIts teins to bind to helper T lymphocytes via CD4 (T4) receptors
We hypothesized to determine whether its target cell specificity could that chemical coupling of lactose residues to a virus could be altered
Summary
(1).These interactions have been shown to be responsible for the observed species and organ specificity. We hypothesized to determine whether its target cell specificity could that chemical coupling of lactose residues to a virus could be altered. To test this hypothesis, chemical modification successfully altered the surface of the we took advantage of the fact that: 1)artificial asial- virus, the modified virus should be able to infect cells derived oglycoproteins can be created by chemical couplingof from non-rodent species that possess asialoglycoprotein lactose to proteins; and 2) viruses that are ecotropic receptors. T o prepareviruswith as little contaminationas possible from serum proteins, producercells were cultured in serumfree Dulbecco's modified Eagle's medium for 3 days. Equal amounts (16.7 pgof RNA, 0.5 mg of viral protein) of modified and unmodified virus in Dulbecco's modified Eagle's medium were added to theculture medium and exposed to cells for 5 days at 37 "C under. Values are means S.E. taken after 5 days of exposure to modified virus
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
