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Expression of a human cytomegalovirus receptor correlates with infectibility of cells
D M Nowlin1, N R Cooper, T Compton
1Department of Immunology, Research Institute of Scripps Clinic, La Jolla, California 92037.
Abstract:
Previous studies have demonstrated that human cytomegalovirus (HCMV) specifically binds to a fibroblast membrane glycoprotein(s) with a molecular mass from 30 to 34 kDa. In this study, the distribution of the putative receptor proteins was analyzed in a variety of cell types, including cell types representative of those that are infected in vivo. Using a sensitive microbinding assay (to score virus attachment) and an indirect detection method (to score HCMV-binding proteins), we found that the 34- and 32-kDa HCMV binding proteins are ubiquitous molecules, broadly distributed among diverse cell types. In addition, the level of virus attachment was found to correlate with the abundance of the 34- and 32-kDa cellular proteins, while the ability of the virus to penetrate cells and initiate infection did not. The results support the hypothesis that the 34- and 32-kDa cellular proteins represent the HCMV (attachment) receptor. The data also support the notion that additional cellular components are required for virus entry and fusion.
Insights
Human cytomegalovirus (HCMV) attaches to cells via ubiquitous 32- and 34-kDa proteins. These proteins are key for HCMV attachment, but not for viral entry or infection initiation.
Area of Science:
- Virology
- Cell Biology
- Molecular Biology
Background:
- Human cytomegalovirus (HCMV) infection is a significant concern, particularly for immunocompromised individuals.
- Previous research identified fibroblast membrane glycoproteins (30-34 kDa) as potential HCMV binding sites.
Purpose of the Study:
- To investigate the distribution of putative HCMV receptor proteins across various cell types.
- To determine the correlation between the abundance of specific cellular proteins and HCMV attachment, entry, and infection.
Main Methods:
- Utilized a sensitive microbinding assay to quantify HCMV attachment to cells.
- Employed an indirect detection method to identify and quantify HCMV-binding proteins.
- Analyzed protein distribution in diverse cell types, including those infected in vivo.
Main Results:
- Identified 32- and 34-kDa cellular proteins as the primary HCMV binding molecules.
- Demonstrated that these receptor proteins are ubiquitously distributed across a wide range of cell types.
- Found a strong correlation between the abundance of 32- and 34-kDa proteins and the level of HCMV attachment.
- Observed that viral entry and subsequent infection initiation were independent of the abundance of these attachment proteins.
Conclusions:
- The 32- and 34-kDa cellular proteins serve as the primary attachment receptors for HCMV.
- Additional cellular factors are necessary for HCMV to penetrate cells and initiate infection.
- This finding clarifies the initial steps of HCMV cellular interaction and infection pathway.