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.

Mannan‐binding lectin reduces CpG DNA‐induced inflammatory cytokine production by human monocytes

“…Toll‐like receptor‐9‐dependent signaling is a vital contributor to innate immune defense against CMV infection . Several studies using in vivo patient models have reported an association between MBL gene polymorphisms and risk of CMV infection , whereas an in vitro study showed that both recombinant and native human MBL inhibit human CMV infection . MBL incubation reportedly reduces phosphorylation of p65 upon CMV stimulation in human embryonic pulmonary fibroblasts , which is consistent with our present finding that MBL inhibits phosphorylation activity of p65 initiated by CpG‐ODN 2006 in monocytes.…”

“…Several studies using in vivo patient models have reported an association between MBL gene polymorphisms and risk of CMV infection , whereas an in vitro study showed that both recombinant and native human MBL inhibit human CMV infection . MBL incubation reportedly reduces phosphorylation of p65 upon CMV stimulation in human embryonic pulmonary fibroblasts , which is consistent with our present finding that MBL inhibits phosphorylation activity of p65 initiated by CpG‐ODN 2006 in monocytes. It should be noted that in the current study we used a type B CpG‐ODN (i.e., CpG‐ODN 2006), which is known to preferentially activate Th1‐like immune responses and proinflammatory responses .…”

High doses of recombinant mannan‐binding lectin inhibit the binding of influenza A(H1N1)pdm09 virus with cells expressing DC‐SIGN

“…A recombinant form of human wild‐type mannan‐binding lectin (rMBL) was produced in CHO cells using a PIRES2‐AcGFP expression vector system (Invitrogen LTD company; Shanghai, China) and purified by mannan–Sepharose 4B affinity chromatography and gel filtration, as reported elsewhere . Human MBL (hMBL) was purified from human serum by passage through mannan–Sepharose 4B column (Sigma‐Aldrich, St. Louis, MO, USA), as described elsewhere .…”

Low Levels of Mannan-Binding Lectin or Ficolins Are Not Associated with an Increased Risk of Cytomegalovirus Disease in HIV-Infected Patients

“…CMV glycoproteins are potential targets for MBL binding which could prevent virion entry into host cells. Alternatively, MBL could recognize these glycoproteins in/on the surface of an infected cell subsequently inducing complement-mediated cell destruction of the viral reservoir (infected cells) [16,17]. In contrast, in a previous study complement activation and C3 deposition on the surface of CMV infected human skin fibroblasts were not dependent on MBL but only on C1q, the initiating molecule of the classical pathway of complement [18].…”