Enveloped Virus Glycoprotein/receptor Interactions

National Institute Of Allergy And Infectious Diseases

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Abstract

Latently infected B cells are believed to be a major reservoir for KSHV, and the virus is believed to be shed from tonsillar B-cells via saliva. Paradoxically, while several irrelevant cell lines (non-B cell, non-human) are permissive for in vitro KSHV infection, human B-cell lines and primary-B cells are notoriously refractory to infection. We performed a strategic search of B lymphomas with the aim of identifying B-cell lines susceptible to KSHV infection. Using a recombinant KSHV encoding EGFP under a constitutive promoter and RFP under a lytic promoter, plus a puromycin-resistance marker, we identified a novel B-cell line (designated B3) that is susceptible to KSHV infection. Following recombinant KSHV exposure, EGFP was detected in nearly 20% of the B3 cells. Viral DNA replication, latency-associated transcription, and viral protein synthesis were detected. HDAC inhibitors induced low-level lytic replication. Puromycin selection yielded cultures in which the entire population was KSHV infected (EGFP-positive). Unlike infected endothelial cells, infected B cells entered lytic replication following B cell receptor crosslinking with antibody (anti-IgM). Preliminary assays have identified surface markers and associated phenotypic properties of the KSHV-permissive cell line.