Influenza virus A subtype H1N1 is inhibited by methylated β-lactoglobulin

Consolidating food safety measures against COVID-19

Background

The world is facing an extraordinarily unprecedented threat from the COVID-19 pandemic triggered by the SARS-CoV-2 virus. Global life has turned upside down, and that several countries closed their borders, simultaneously with the blockage of life cycle as a result of the shutdown of the majority of workplaces except the food stores and some few industries.

Main body

In this review, we are casting light on the nature of COVID-19 infection and spread, the persistence of SARS-CoV-2 virus in food products, and revealing the threats arising from the transmission of COVID-19 in food environment between stakeholders and even customers. Furthermore, we are exploring and identifying some practical aspects that must be followed to minimize infection and maintain a safe food environment. We also present and discuss some World Health Organization (WHO) guidelines-based regulations in food safety codes, destined to sustain the health safety of all professionals working in the food industry under this current pandemic.

Conclusion

The information compiled in this manuscript is supporting and consolidating the safety attributes in food environment, for a prospective positive impact on consumer confidence in food safety and the citizens’ public health in society. Some research is suggested on evaluating the use and potentiality of native and chemical modified basic proteins as possible practices aiming at protecting food from bacterial and viral contamination including COVID-19.

Antiviral properties of whey proteins and their activity against SARS-CoV-2 infection

Native and chemically modified whey proteins and their peptide derivatives are encountering the interest of nutraceutical and pharmaceutical industries, due to the numerous properties, ranging from antimicrobial to immunological and antitumorigenic, that result in the possibility to employ milk and its protein components in a wide range of treatment and prevention strategies. Importantly, whey proteins were found to exert antiviral actions against different enveloped and non-enveloped viruses. Recently, the scientific community is focusing on these proteins, especially lactoferrin, since in vitro studies have demonstrated that they exert an important antiviral activity also against SARS-CoV-2. Up-to date, several studies are investigating the efficacy of lactoferrin and other whey proteins in vivo. Aim of this review is to shed light on the most relevant findings concerning the antiviral properties of whey proteins and their potential applications in human health, focussing on their application in prevention and treatment of SARS-CoV-2 infection.

H5N1 Avian Flu Infection in Hubbard Broiler Chicken Can Be Prevented or Cured by Methylated Soy Protein During 42 Days Rearing

Methylated soy protein (MSP) which is positively charged with enhanced hydrophobicity may have antiviral action. This study is verifying if MSP can act inhibit H5N1 inside an animal model. Five groups of Hubbard chicks were challenged at the 25th day of the experiment with AIV virus (H5N1; 0.1 × 10⁵ EID₅₀/mL); 1 group did not receive any treatment (positive control), 2 groups (protective) received treatments before and after the challenge (0.1-0.2 g/L in drinking water ad libitum), and 2 groups (curative) received them only after the challenge. The positive control recorded 100% mortality after 3-5 days of infection. Chicken receiving MSP (0.2 g/L), delayed reaching to 100% mortality to the 7^th day after infection, while those receiving MSP low level (0.1 g/L) could achieve 100% survival during the whole incubation period (42 days), either as a preventive or curative approach. H5N1 virus was not detected in the tracheal and cloacal swabs of the groups receiving 0.1 g/L, opposite to the positive control. The low level of MSP (0.1 g/L) reduced the viral titer to about 1% of the positive control in the protective and curative groups after 5 days of infection, and could maintain the bird body-weight, liver and kidney function, and histopathological status within the normal values. Humoral and TLC response in the group receiving both the virus and the MSP (0.1 g/L) may refer to a possibility that MSP-weakened virus has transformed into a vaccine-like material eliciting host immunity.

Antiviral Action of Native and Methylated Lactoferrin and β-Lactoglobulin against Potato Virus Y (PVY) Infected into Potato Plants Grown in an Open Field

Potato plants are liable to PVY infection without efficient control. Therefore, they were cultivated under greenhouse and open field conditions, artificially infected with PVY and then treated after 15 days of infection with native lactoferrin (LF) and native β-lactoglobulin (BL) and their esterified forms, MLF (methylated lactoferrin) and BLM (methylated β-lactoglobulin) to test the efficiency of this approach. Viral replication was inhibited by the applied substances, particularly the methylated forms, in a concentration-dependent manner, where the concentration of 500 μg·mL^-1 was sufficient for plant protection against the PVY infection. An open field experiment showed that one single application of the antiviral substance was enough for maximum inhibitory action against PVY. The modified milk proteins induced higher inhibitory action on PVY virus replication in the plants, compared to their native forms, which was reflected by potato growth and yield. Using the dot blot hybridization and RT-PCR techniques to detect PVY in the experimental plants showed the supremacy of native and esterified LF in inhibiting the targeted virus. The generally observed scanning electronic microscopy (SEM) structural deformations and irregular appearance in PVY particles when treated with MLF and BLM revealed their direct action. BLM, MLF and LF are efficient antiviral agents against PVY. They can not only abolish the observed PVY-induced reduction in potato growth and tuber yield, but also further increase them to higher levels than negative control.

Antivirals against animal viruses

Antivirals are compounds used since the 1960s that can interfere with viral development. Some of these antivirals can be isolated from a variety of sources, such as animals, plants, bacteria or fungi, while others must be obtained by chemical synthesis, either designed or random. Antivirals display a variety of mechanisms of action, and while some of them enhance the animal immune system, others block a specific enzyme or a particular step in the viral replication cycle. As viruses are mandatory intracellular parasites that use the host's cellular machinery to survive and multiply, it is essential that antivirals do not harm the host. In addition, viruses are continually developing new antiviral resistant strains, due to their high mutation rate, which makes it mandatory to continually search for, or develop, new antiviral compounds. This review describes natural and synthetic antivirals in chronological order, with an emphasis on natural compounds, even when their mechanisms of action are not completely understood, that could serve as the basis for future development of novel and/or complementary antiviral treatments.

Antiviral activities of whey proteins

Milk contains an array of proteins with useful bioactivities. Many milk proteins encompassing native or chemically modified casein, lactoferrin, alpha-lactalbumin, and beta-lactoglobulin demonstrated antiviral activities. Casein and alpha-lactalbumin gained anti-HIV activity after modification with 3-hydroxyphthalic anhydride. Many milk proteins inhibited HIV reverse transcriptase. Bovine glycolactin, angiogenin-1, lactogenin, casein, alpha-lactalbumin, beta-lactoglobulin, bovine lactoferrampin, and human lactoferrampin inhibited HIV-1 protease and integrase. Several mammalian lactoferrins prevented hepatitis C infection. Lactoferrin, methylated alpha-lactalbumin and methylated beta-lactoglobulin inhibited human cytomegalovirus. Chemically modified alpha-lactalbumin, beta-lactoglobulin and lysozyme, lactoferrin and lactoferricin, methylated alpha-lactalbumin, methylated and ethylated beta-lactoglobulins inhibited HSV. Chemically modified bovine beta-lactoglobulin had antihuman papillomavirus activity. Beta-lactoglobulin, lactoferrin, esterified beta-lactoglobulin, and esterified lactoferrindisplayed anti-avian influenza A (H5N1) activity. Lactoferrin inhibited respiratory syncytial virus, hepatitis B virus, adenovirus, poliovirus, hantavirus, sindbis virus, semliki forest virus, echovirus, and enterovirus. Milk mucin, apolactoferrin, Fe³⁺-lactoferrin, beta-lactoglobulin, human lactadherin, bovine IgG, and bovine kappa-casein demonstrated antihuman rotavirus activity.

Inhibitory effect of esterified lactoferin and lactoferrin against tobacco mosaic virus (TMV) in tobacco seedlings

The inhibitory effects of esterified lactoferrin (ELF) and lactoferrin (LF) against tobacco mosaic virus (TMV) in tobacco seedlings and the underlying mechanism were investigated. ELF and LF significantly inhibited viral infection and TMV multiplication in tobacco plants. ELF showed a higher inhibition effect against TMV than LF treatment in a dose and time-dependent way. Moreover, ELF induced a higher increase in the levels of transcription of pathogenesis-related (PR) protein genes [acidic PRs (PR-1a, PR-2, PR-3, PR-5) and basic PR-1] and defense-related enzymes [phenylalanine ammonia lyase (PAL, EC 4.3.1.5), and 5-epi-aristolochene synthase (EAS, EC 2.5.1.35)] both locally and systemically, in correlation with the induction of resistance against tobacco mosaic virus. Furthermore, ELF also induced accumulation of salicylic acid, SA 2-O-β-D-glucoside and H2O2. These results suggested that ELF and LF could control TMV incidence and the mechanism might attribute to activate the expression of a number of defense genes.

Effectiveness of esterified whey proteins fractions against Egyptian Lethal Avian Influenza A (H5N1)

Background

Avian influenza A (H5N1) virus is one of the most important public health concerns worldwide. The antiviral activity of native and esterified whey proteins fractions (α- lactalbumin, β- lactoglobulin, and lactoferrin) was evaluated against A/chicken/Egypt/086Q-NLQP/2008 HPAI (H5N1) strain of clade 2.2.1 (for multiplicity of infection (1 MOI) after 72 h of incubation at 37°C in the presence of 5% CO₂) using MDCK cell lines.

Result

Both the native and esterified lactoferrin seem to be the most active antiviral protein among the tested samples, followed by β- lactoglobulin. α-Lactalbumin had less antiviral activity even after esterification.

Conclusion

Esterification of whey proteins fractions especially lactoferrin and β-lactoglobulin enhanced their antiviral activity against H5N1 in a concentration dependent manner.