Human mannose‐binding lectin inhibits human cytomegalovirus infection in human embryonic pulmonary fibroblast

Abstract

A limited number of drugs have been used for treatment of human cytomegalovirus (HCMV), all sharing the similar antiviral mechanism of inhibiting virus replication. This study investigates the anti-HCMV activities of mannose-binding lectin (MBL) from blocking virus entry and inhibiting virus spread. Recombinant human MBL was produced in CHO cells and native human MBL was isolated from human serum. A HCMV neutralization test was performed by pre-treating HCMV with each diluted MBL solution. Then the treated HCMV was inoculated onto the human embryonic pulmonary fibroblasts (HELF), which was followed by HCMV-DNA detection, PP65 positivity examination and confocal imaging of the infected cells. To test the activity of MBL in inhibiting viral spreading after viral invasion, HCMV growth inhibition test was performed. The infected cells were incubated with each diluted MBL, every 24 h, the supernatant was tested for HCMV-DNA. After 72 h, cells were collected for HCMV-DNA and PP65 examination. Then the cytopathic effect was observed and cell viability was measured at the 5 days after infection. HCMV neutralization test revealed 10 μg/mL MBL significantly decreased the HCMV invasion in HELF and the anti-HCMV activity can be blocked by 20 mg/mL mannan. HCMV growth inhibition test indicated that at 48 h after HCMV invasion, the HCMV-DNA level in the culture supernatant with 10 μg/mL MBL was lower than the control. After 72 h, both the HCMV-DNA levels and PP65 positivity in cells incubated with MBL were reduced. This is the first to report on the anti-HCMV activities of MBL by in vitro studies.