BREAKING! COVID-19 News: Vitro Study Involving Vero Cells Shows That Whey Protein Especially From Human Breast Milk Inhibits SARS-CoV-2 Coronavirus
: Researchers from Peking University Health Science Center-Beijing, Beijing University of Chemical Technology and Nanjing University Medical School in a new study have reported that different kinds of whey protein obtained from different sources ie cow’s or goat milk exhibited inhibitory properties against the SARS-CoV-2 coronavirus in vitro studies involving vero cells. However whey protein from human milk exhibited greater efficacy against the virus.
The research findings are published on a preprint server and are currently being peer-reviewed. https://www.biorxiv.org/content/10.1101/2020.08.17.254979v1
Numerous medical researchers had reported the effects of SARS-CoV-2 infection on pregnancy and the virus has even been detected in breast milk. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31181-8/fulltext
but there has been other studies that dispute this. https://jamanetwork.com/journals/jama/fullarticle/2769825
However this new study shows that whey protein in human breast milk efficiently prevents infection with SARS-CoV-2 as well as post-entry viral replication.
Milk typically contains an abundance of useful components such as proteins, minerals, vitamins, and antimicrobial compounds. It antagonizes the activity of viruses like hepatitis C virus (HCV), human cytomegalovirus (HCMV) and human immunodeficiency virus (HIV). Milk lactoferrin inhibits the intracellular replication of HCV.
Whey proteins from breast milk are in liquid form and very easy to digest. Whey from human breast milk is rich in a variety of antibodies, lactoferrin, lysozyme, proteins; hormones and nutrients which helps a baby fight off infections and disease.
The study team initially aimed to examine the activity of whey protein in human breast milk against SARS-CoV-2 and the pangolin coronavirus GX_P2V, which is closely related to it.
The study team found that when Vero cells (Vero cells are a lineage of cells used in cell cultures and vitro studies. The 'Vero' lineage was isolated from kidney epithelial cells extracted from an African
green monkey) infected with pseudovirus expressing SARS-CoV-2 antigens were exposed to the presence of breast milk, all the milk samples from different donors efficiently inhibited over 98% of infection, in both the original condition and at serial two-fold dilutions.
Different samples showed different EC50 ie the 50% of maximal effect, from 0.02 mg/mL to 0.25 mg/mL. At the same time, the half-maximal cytotoxicity concentration CC50 was over 3 mg/mL, showing the high safety profile.
It was also observed that when the in vitro experiment was repeated with the pangolin CoV, inhibition occurred to almost 100%, and dose-dep
endent inhibition was observed following two-fold serial dilutions. The EC50 ranged between donors, from 0.34 mg/mL to 0.79 mg/mL, while the milk promoted cell proliferation.
The study also found that at varying concentrations from 0.16 mg/mL to 4 mg/mL, human breast milk showed a dose-dependent inhibition of viral infection. When the supernatant was used to infect other cells, plaque assays showed that all control dishes were positive for the live virus, and the titer went down with dilution of supernatant. However, when treated with 4 mg breast milk, no live virus was found in any dish. At 0.16 mg/mL, live virus was detected below a supernatant dilution of 1: 1,000 and even below 1: 10,000. Thus, human breastmilk inhibits infectious particle production
The study team also showed that whey protein from cow’s and goat’s milk also inhibits the virus in Vero cells, even when obtained from commercial cow’s milk. These results were obtained in pseudoviruses as well. However, human skimmed breast milk was markedly more effective than cow or goat whey protein.
Importantly the whey protein in breast milk was inactivated by heating to 90 °C for 10 minutes, as well as by treating with protease K. This showed that whey protein itself was the antiviral factor in the milk.
The researchers also found that the SARA-CoV-2 coronavirus was inefficiently inhibited by lactoferrin from human milk, goat milk, and recombinant lactoferrin compared to human breast milk.
These results were repeated with the pangolin CoV. Thus lactoferrin does not appear to be responsible for the antiviral effects of human breastmilk by itself.
Subsequently, IgA antibody from recovered COVID-19 patients was mixed with the human breast milk. This was because the breast milk samples were obtained in 2017, before the onset of the pandemic. At all dilutions, the IgA failed to produce any alteration in the rate of infection, proving that its presence is not responsible for the efficient inhibitory activity of human breastmilk.
The research findings also show that the presence of whey protein inhibits viral attachment as well as the entry process. The study team also observed that after viral entry, treatment with human breast milk inhibited replication at high efficiency for both viruses. Thus it was safe to say That Whey Inhibits Viral Attachment, Entry And Post-Entry Replication.
The vitro research used SARS-CoV-2 pseudoviruses for reasons of biosafety, in addition to the pangolin CoV.
Both are considered to be good alternative models to study various characteristics of the wildtype virus without the requirement for biosafety level 2 facilities.
Significantly the observation that human breast milk has potent antiviral activity against these two different but closely related coronaviruses in two different cell lines indicates that it could prevent infection by and replication of SARS-CoV-2.
Also it must be noted that the same inhibitory capacity is present in whey protein from other species though at lower efficiency. Antiviral factors seem to be more abundant in human breast milk compared to that of other species.
Importantly lactoferrin and IgA do not appear to account for the antiviral activity, especially since lactoferrin is much lower in non-human milk.
The study suggests that more research is required to elucidate the mechanism of anti-SARS-CoV-2 activity of whey protein of human breast milk. This could help develop effective antiviral drugs to help treat COVID-19.
The team is working with researcher from the US to further this study into identifying the active components in whey from human breast milk that has the efficacy against the SARS-CoV-2 coronavirus and also the relevant cellular pathways or mode of action.
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