S-layer proteins of Lactobacillus acidophilus inhibits JUNV infection.

Abstract

It has been previously described that S-layer binds to the C-type lectin DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN, CD209). It was also shown that DC-SIGN is a cell-surface adhesion factor that enhances viral entry of several virus families. Among those, Junin virus (JUNV) entry is enhanced in cells expressing DC-SIGN and for that reason surface-layer protein (S-layer) of Lactobacillus acidophilus ATCC 4365 was evaluated as a possible JUNV inhibitor. Experiments using 3T3 cells stably expressing DC-SIGN, showed an almost complete inhibition of JUNV infection when they were treated with S-layer in a similar extend as the inhibition shown by mannan. However no inhibition effect was observed in 3T3 wild type cells or in 3T3 cells expressing liver/lymph node-specific ICAM-3 grabbing nonintegrin (L-SIGN or DC-SIGNR or CD209L). Treatments with S-layer during different times in the infection demonstrated that inhibition was only observed when S-layer was presented in early stages of the viral infection. This inhibition does not involve the classic recognition of mannose by this C-type lectin as the S-layer showed no evidence to be glycosylated. In fact, the highly basic nature of the S-layer (pI>9.5) seems to be involved in electrostatic interactions between DC-SIGN and S-layer, since high pH abolished the inhibitory effect on infection cause by the S-layer. In silico analysis predicts a Ca(2+)-dependant carbohydrate recognition domain in the SlpA protein. This novel characteristic of the S-layer, a GRAS status protein, contribute to the pathogen exclusion reported for this probiotic strain and may be applied as an antiviral agent to inhibit several kinds of viruses.

• Authors: María Guadalupe Martínez, Mariano Prado Acosta, Nélida A Candurra, Sandra M Ruzal
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 422 Issue 4 Pg. 590-5 (Jun 15 2012) ISSN: 1090-2104 [Electronic] United States
• PMID: 22595457 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Elsevier Inc. All rights reserved.

Chemical References

• Antiviral Agents
• Bacterial Proteins
• Cell Adhesion Molecules
• DC-specific ICAM-3 grabbing nonintegrin
• Lectins, C-Type
• Membrane Glycoproteins
• Receptors, Cell Surface
• S-layer proteins
• surface layer protein A, Bacteria

Topics

• 3T3 Cells
• Amino Acid Sequence
• Animals
• Antiviral Agents (chemistry, isolation & purification, pharmacology)
• Arenaviridae Infections
• Bacterial Proteins (isolation & purification, pharmacology)
• Cell Adhesion Molecules (genetics, metabolism)
• Chlorocebus aethiops
• Consensus Sequence
• Junin virus (drug effects)
• Lactobacillus acidophilus
• Lectins, C-Type (genetics, metabolism)
• Membrane Glycoproteins (chemistry, isolation & purification, pharmacology)
• Mice
• Molecular Sequence Data
• Receptors, Cell Surface (genetics, metabolism)
• Vero Cells
• Virus Internalization (drug effects)