Laminin reduces HSV-1 spread from cell to cell in human keratinocyte cultures

Herpes simplex virus-1 (HSV-1) infects epidermal cells where it replicates and spreads from cell to cell. While some of the viral factors responsible for cell-to-cell spread are known, the host cell molecules and structures which are utilized by HSV-1 during spread are not well studied. Here we report that a laminin substrate reduced the ability of HSV-1 to spread from cell to cell in cultures of a human keratinocyte cell line (HaCaT). Laminin did not reduce spread of the virus by decreasing the viral replication rate. However, laminin did stimulate the formation of tight junctions between HaCaT cells, suggesting that tight junctions can affect cell-to-cell spread of HSV-1. Since laminin is an abundant component of the basement membrane in vivo, culturing cells on laminin may provide an assay which more accurately reflects the rate and mechanism of HSV-1 cell-to-cell spread in vivo.