Antiviral activity of purified human breast milk mucin.
ABSTRACT Human breast milk is known to contain numerous biologically active components which protect breast fed infants against microbes, viruses, and toxins. The purpose of this study was to purify and characterize the breast milk mucin and determine its anti-poxvirus activity. In this study human milk mucin, free of contaminant protein and of sufficient quantity for further analysis, was isolated and purified by Sepharose CL-4B gel filtration and cesiumchloride density-gradient centrifugation. Based on the criteria of size and appearance of the bands and their electrophoretic mobility on sodium dodecyl sulfate polyacrylamide-gel electrophoresis, Western blotting together with the amino acid analysis, it is very likely that the human breast milk mucin is MUC1. It was shown that this breast milk mucin inhibits poxvirus activity by 100% using an inhibition assay with a viral concentration of 2.4 million plaque-forming units/ml. As the milk mucin seems to aggregate poxviruses prior to their entry into host cells, it is possible that this mucin may also inhibit other enveloped viruses such as HIV from entry into host cells.
SourceAvailable from: Corena De Beer[Show abstract] [Hide abstract]
ABSTRACT: Background: The HIV-AIDS pandemic is prevalent in sub-Saharan Africa. Breastfeeding is a risk factor, with transmission from mother to child being as high as 40%. Objectives: To determine the antiviral activity of crude breast milk and its purified mucins MUC1 and MUC4 against HIV-1 in patients who were HIV positive compared to those who were not. Methods: Twenty-one human milk samples were taken from both groups. Breast milk mucins were purified by density-gradient ultracentrifugation in caesium chloride and analyzed by SDS-PAGE, Western blotting and amino acid content. The inhibition of the virus by crude milk and purified mucin was assayed by an in vitro HIV-1 p24 assay. Results: SDS-PAGE for purified mucin showed several high-molecular-weight bands for the HIV-negative group and prominently stained single bands on the stacking gel with faintly periodic acid Schiff-positive glycoprotein bands observed in some cases in the running gel for the HIV-positive mucins. Western blot analysis identified the mucins in both groups to be MUC1 and MUC4. Both mucins showed more intensity on Western blotting for the HIV-positive group. There was no difference in the content of serine, threonine and proline of purified mucins for both groups. HIV-1 was not inhibited by crude breast milk from normal (13/14 samples) and infected individuals (19/19 samples). Fifteen of 20 and 16/18 samples of purified mucin from the uninfected and HIV-positive groups, respectively, inhibited the virus. Conclusions: Crude breast milk does not inhibit HIV-1, whilst purified mucins do in an in vitro assay. © 2014 S. Karger AG, Basel.Neonatology 02/2014; 105(3):211-217. DOI:10.1159/000357201 · 2.57 Impact Factor
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ABSTRACT: The (glyco)proteins in the milk fat globule membrane (MFGM) have advantageous effects, mainly related to prevention of bacterial adhesion to the gastro-intestinal wall. The aim of this study was to investigate the effects of MFGM fractions enriched with various (glyco)proteins on the metabolism, community structure, and anti-adhesive properties of the colonic microbiota. Five MFGM fractions were obtained, which varied in the type of (glyco)proteins present and lipid content. All these fractions, but especially the fraction which was enriched in mucin 1 (MUC1), stimulated short chain fatty acid and ammonium production. Butyrate, as a percentage of total short chain fatty acids, increased significantly by 4–9% compared with the control upon incubation of colonic microbiota with MFGM (glyco)proteins for 48 h. The bacterial community structure changed upon incubation with MFGM (glyco)proteins. MUC1 and the MFGM fraction containing all MFGM (glyco)proteins reduced bacterial adhesion. These effects were reduced in the presence of lipids.International Dairy Journal 10/2013; 32(2):99–109. DOI:10.1016/j.idairyj.2013.05.001 · 2.30 Impact Factor
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ABSTRACT: Background: Sub-Saharan Africa is the world's worst HIV-AIDS affected region. More interventions to manage this pandemic are urgently required. Transmission of the virus through an exchange of saliva is rarely known to occur. This project sought to verify statistically previous findings in our laboratory, that crude saliva from uninfected individuals together with its purified mucin components inhibited HIV-1, whilst mucins from infected saliva did not show this inhibition, in an in vitro assay. Methods: Saliva was extracted in 4 M guanidinium hydrochloride and proteolytic inhibitors at pH 6.5, followed by the isolation of MUC5B and MUC7 by Sepharose 4B gel filtration and further purification of these mucins by density-gradient ultra-centrifugation in caesium chloride. Agarose gel electrophoresis, Western blotting and amino acid compositional analysis determined the size, purity and identity of the mucins. The inhibitory activity of crude saliva and purified MUC5B and MUC7, from HIV negative (n=20) and HIV positive (n=20) donors, was tested by their incubation with subtype C HIV-1 and subsequent infection of peripheral blood mononuclear cells (PBMCs). PCR was done on tandem repeat regions of MUC5B and MUC7 DNA to investigate whether any association existed between gene polymorphism and susceptibility to infection. Results: There was an inter-individual variation in the amounts of MUC5B and MUC7 in saliva. In contrast to previous studies, crude saliva and purified mucins from both HIV negative and HIV positive individuals inhibited the infection of HIV-1 in an in vitro assay. DNA analysis of the tandem repeat regions of MUC5B and MUC7 revealed no difference between groups. Conclusions: Crude saliva and its mucins, MUC5B and MUC7, from both uninfected controls and HIV positive individuals inhibited HIV-1 in an in vitro assay.Virology Journal 08/2012; 9:177. DOI:10.1186/1743-422X-9-177 · 2.09 Impact Factor