Immune System: A protein found in mother’s milk called Lactoferrin has been found to demonstrate antiviral activity in preclinical trials. It impedes viral binding to cell membranes, while activating immune defenses.
Viral infections are a major cause of disease and death globally, from the common cold and flu to newer threats such as the SARS-CoV-2 coronavirus that causes the deadly COVID-19.
To date protein lactoferrin has shown potent antiviral activity in preclinical and human clinical studies. It attacks viruses at several points in their lifecycle, through various mechanisms.1-4
Although lactoferrin is produced in the body, it can also be absorbed through oral intake, bolstering the body’s defenses.5
Lactoferrin could provide an additional layer of defense to reduce the risk of contracting viral illnesses and to diminish their severity.
Unfortunately, viruses are unlike other infectious pathogens. For one thing, they cannot grow and reproduce on their own. Viruses must hijack the controls of a host cell to survive and replicate. Also, they are tiny, far smaller than microscopic bacteria and fungi.6
Typically, viruses are made up of miniscule packages of protein that surrounds genetic material. When they find a suitable host cell, they invade, then use that cell to produce new copies of the virus, which can go on to infect other cells.
The initial step in this process occurs after the virus enters the body, often through the lining of respiratory airways or the digestive system. Viruses contain surface proteins that are able to recognize specific surface features of cells. This allows them to attach to cells and gain entry.
The moment it gets into the cell, the virus takes control of the cellular machinery to make copies of its genetic material and proteins that are then reassembled into new virus particles.
The compound lactoferrin helps protect by impeding the invasion and growth of viruses at multiple steps in this process.
The protein Lactoferrin is a found naturally in milk. It’s also produced in other bodily secretions, including tears and saliva, and by some immune system cells.4
Interestingly, Lactoferrin is found in highest amounts in colostrum, the first type of mother’s milk produced after a baby is born. It has remarkable powers to shield infants from infection before their own immune systems have fully developed.
In human adults, it is an important component of defenses against infections.
In mucous, saliva, and other secretions, lactoferrin helps prevent pathogens from gaining entry through the linings of the oral cavity, nasal cavity, airways, and digestive system.
One significant feature of lactoferrin is the diversity of viruses it can shield against. It has been shown to possess robust antiviral activity against different types of virus, from those that cause the common cold and flu, to HIV and hepatitis B and C viruses.4
The most distinctive way lactoferrin defends against viral infections is by disrupting viruses from binding to cells. 1-3,7 This helps stop the virus in its tracks, before it has a chance to cause any problems. If the virus cannot attach to and enter cells, it cannot cause illness.
The protein lactoferrin does this in two different ways:
-Firstly it binds to the virus directly, blocking the viruses’ surface proteins’ ability to recognize binding sites on the surface of cell membranes.
-Secondly, it binds to surface sites on the cell’s outer membrane that are targeted by viruses.
As an example, a compound found on cell surfaces, called heparan sulfate, is a common target for various viruses.
Various research have shown that lactoferrin binds to structures containing heparan sulfate, which can prevent viruses from recognizing and entering the cell.7,8
To date, lactoferrin has been shown in laboratory, animal, and preclinical research to help protect against a huge list of viruses.1-4,7,8,10-12 including:
-the different types of viruses that cause the common cold,4
-the various types of viruses that cause flu, including several different strains of influenza A (even the H1N1 subtype that caused a global outbreak in 2009),4,11
-the various types of viruses that cause gastroenteritis (stomach flu) 4
-Herpes simplex virus,4,12
-Human immunodeficiency virus (HIV), which causes AIDS,1,2,4
-Hepatitis B virus,1,3,8
-Hepatitis C virus,1,2,8
-Respiratory syncytial virus (RSV),1,11
-Dengue virus, the cause of dengue fever,7,8
-Epstein-Barr virus (EBV).12
The protein lactoferrin also has indirect antiviral effects. It helps the body fight against a virus by activating immune defenses.
It activates natural killer cells and increases their number.5,9 These immune cells are equipped to recognize abnormal cells, including those infected by viruses, and eliminate them. This can help prevent the spread of a virus in the body.
The unique protein also stimulates the production of other antiviral compounds, including the signaling proteins known as interferons.2,4 One of the important ways that interferons promote immunity is to signal to surrounding cells that viruses are present, and help activate antiviral mechanisms to prevent growth and spread of those viruses.
It has been found that lactoferrin may also help block the ability of viruses to reproduce even if they’re already inside cells,1,4limiting the spread of the virus, potentially reducing the severity of the resulting illness.
Consuming lactoferrin orally may reduce both the incidence and severity of disease caused by viruses. The extra protection afforded by lactoferrin could make a difference in helping to lessen the impact of these illnesses.
In a research study, healthy women taking oral lactoferrin experienced a reduced onset of both common-cold-like and gastroenteritis symptoms.13
In other clinical studies, lactoferrin was effective for reducing the symptoms of viral gastroenteritis, including those caused by rotavirus and norovirus. Oral lactoferrin reduced the incidence and severity of the symptoms of these illnesses.4
Individuals taking 100 mg of lactoferrin six or seven days a week had an approximately 4-fold decrease in the incidence of viral gastroenteritis compared to people who took it only once a week.4
The new coronaviruses of differing types have caused severe acute respiratory syndromes such as the SARS epidemic in Asia that killed over 700 people in 2003.14
This same family of SARS viruses emerged this year as the cause of COVID-19.
COVID-19 is too new to have been studied in depth, but it shares many features with other coronaviruses. These include the SARS and MERS viruses that caused previous highly serious infectious disease outbreaks.
The protein lactoferrin shows promise in helping to defend against SARS-type coronaviruses in at least two different ways.
A research study in 2011 showed that lactoferrin was effective at blocking a model of a SARS-type coronavirus from entering host cells.7 It did this by preventing binding of viral elements to the heparan sulfate compounds on the surface of the target cells.
Considering the lack of an effective vaccine or drug treatment for so many viral illnesses, lactoferrin is a promising new tool in the defense against viral illnesses.
Numerous research studies have demonstrated that it can boost healthy immune function, which protects against a variety of pathogen types. Various disease-causing bacteria have been found to be susceptible to the actions of lactoferrin.2,3
Though there is no concrete proof of the efficacy of lactoferrin against the SARS-CoV-2, more studies should be conducted to test it actual potential against this particular novel coronavirus.
For more on the Immune System and ways to boost it and also protect it , keep reading Thailand Medical News.
1.Berlutti F, Pantanella F, Natalizi T, et al. Antiviral properties of lactoferrin–a natural immunity molecule. Molecules. 2011Aug 16;16(8):6992-7018.
2.Drago-Serrano ME, Campos-Rodriguez R, Carrero JC, et al. Lactoferrin: Balancing Ups and Downs of Inflammation Due to Microbial Infections. Int J Mol Sci. 2017 Mar 1;18(3).
3.Moreno-Exposito L, Illescas-Montes R, Melguizo-Rodriguez L, et al. Multifunctional capacity and therapeutic potential of lactoferrin. Life Sci. 2018 Feb 15;195:61-4.
4.Wakabayashi H, Oda H, Yamauchi K, et al. Lactoferrin for prevention of common viral infections. J Infect Chemother. 2014 Nov;20(11):666-71.
5.Zhang Y, Lima CF, Rodrigues LR. Anticancer effects of lactoferrin: underlying mechanisms and future trends in cancer therapy. Nutr Rev. 2014 Dec;72(12):763-73.
6.Available at: https://www.ncbi.nlm.nih.gov/books/NBK8149/. Accessed May 23, 2020.
7.Lang J, Yang N, Deng J, et al. Inhibition of SARS pseudovirus cell entry by lactoferrin binding to heparan sulfate proteoglycans. PLoS One. 2011;6(8):e23710.
8.Chen JM, Fan YC, Lin JW, et al. Bovine Lactoferrin Inhibits Dengue Virus Infectivity by Interacting with Heparan Sulfate, Low-Density Lipoprotein Receptor, and DC-SIGN. Int J Mol Sci. 2017 Sep 12;18(9).
9.Kuhara T, Yamauchi K, Tamura Y, et al. Oral administration of lactoferrin increases NK cell activity in mice via increased production of IL-18 and type I IFN in the small intestine. J Interferon Cytokine Res. 2006 Jul;26(7):489-99.
10.Pietrantoni A, Di Biase AM, Tinari A, et al. Bovine lactoferrin inhibits adenovirus infection by interacting with viral structural polypeptides. Antimicrob Agents Chemother. 2003 Aug;47(8):2688-91.
11.Scala MC, Sala M, Pietrantoni A, et al. Lactoferrin-derived Peptides Active towards Influenza: Identification of Three Potent Tetrapeptide Inhibitors. Sci Rep. 2017 Sep 6;7(1):10593.
12.Zheng Y, Zhang W, Ye Q, et al. Inhibition of Epstein-Barr virus infection by lactoferrin. J Innate Immun. 2012;4(4):387-98.
13.Oda H, Nakano M, Wakabayashi H, et al. Questionnaire survey on the subjective effects of a lactoferrin supplement. Jpn J Complement Altern Med. 2012;9(2):121-8.
14.Available at: https://www.cdc.gov/sars/about/fs-sars.html. Accessed May 23, 2020.