lactoferrin and Caliciviridae-Infections

Although lactoferrin has many biological functions, the host-protective effects against pathogenic microorganisms including bacteria, fungi, and viruses are regarded as one of the most important. Here, we review research on the protective role of lactoferrin administration against common viral infections. Many studies have shown the in vitro antiviral activity of lactoferrin against viral pathogens that cause common infections such as the common cold, influenza, gastroenteritis, summer cold, and herpes, where lactoferrin inhibits mainly viral attachment to the target cells. Recently, studies indicating the in vivo protective effects of lactoferrin by oral administration against common viral infections have been increasing. For instance, norovirus is an extremely important emerging human pathogen that causes a majority of gastroenteritis outbreaks worldwide that may be a target candidate for lactoferrin. Lactoferrin consumption reduced the incidence of noroviral gastroenteritis in children and a similar effect was observed in a wide range of ages in a preliminary survey. A recent in vitro study reported that lactoferrin inhibits both cellular attachment of the murine norovirus, a virus closely-related to the human norovirus, and viral replication in the cells by inducing antiviral cytokines interferon (IFN)-α/β. Lactoferrin administration also enhances NK cell activity and Th1 cytokine responses, which lead to protection against viral infections. In conclusion, lactoferrin consumption may protect the host from viral infections through inhibiting the attachment of a virus to the cells, replication of the virus in the cells, and enhancement of systemic immune functions.

Topics: Anti-Infective Agents; Caliciviridae Infections; Common Cold; Gastroenteritis; Herpes Simplex; Humans; Influenza, Human; Lactoferrin; Norovirus; Rotavirus Infections; Seasons

The intestinal immune and inflammatory responses of Norovirus (NoV) are poorly defined. The objective of this study was to investigate fecal cytokine and lactoferrin profiles in response to NoV gastroenteritis in travelers. Both fecal cytokines and fecal lactoferrin were measured for NoV-associated diarrhea (N = 7), mixed infection of NoV and enterotoxigenic E. coli (ETEC)-associated diarrhea (N = 10) and in pathogen-negative diarrhea cases (N = 19). Both IL-2 and IFN-gamma were significantly increased in NoV-associated diarrhea specimens, suggesting a predominant Th1 immune response to NoV infection in the gut. When a mixed infection of NoV and ETEC occurred, a combined Th1/Th2 response was observed suggesting a dual immune response secondary to infection by both pathogens. Intestinal inflammation associated with increased fecal lactoferrin, important in bacterial enteric infection, was not found in NoV-associated gastroenteritis.

Topics: Adult; Biomarkers; Caliciviridae Infections; Cytokines; Diarrhea; Feces; Humans; Inflammation; Intestinal Mucosa; Lactoferrin; Middle Aged; Norovirus; Travel

To characterize the effect of bovine lactoferrin and lactoferricin B against feline calicivirus (FCV), a norovirus surrogate and poliovirus (PV), as models for enteric viruses.. Crandell-Reese feline kidney (CRFK) cells were used for the propagation of FCV and monkey embryo kidney (MEK) cells for PV. The assays included visual assessment of cell lines for cytopathic effects and determination of the percentage cell death using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium] dye reduction assay. Incubation of bovine lactoferrin with CRFK cells either prior to or together with FCV inoculation substantially reduced FCV infection. In contrast, the interference of lactoferrin with the infection of cells with PV was demonstrated only when lactoferrin was present with cell lines and virus for the entire assay period. Using indirect immunofluorescence, lactoferrin was detected on the surface of both CRFK and MEK cells, suggesting that the interference of viral infection may be attributed to lactoferrin binding to the surfaces of susceptible cells, thereby preventing the attachment of the virus particles. Lactoferricin B, a cationic antimicrobial peptide derived from the N-terminal domain of bovine lactoferrin, reduced FCV but not PV infection.. Lactoferrin was shown to interfere with the infection of cells for both FCV and PV. However, lactoferricin B showed no interference of infection with PV and interference with infection for FCV required the presence of lactoferricin B together with the cell line and virus.. An in vitro basis is provided for the effects of bovine lactoferrin and lactoferricin B in moderating food-borne infections of enteric viruses.

Topics: Animals; Antiviral Agents; Caliciviridae Infections; Calicivirus, Feline; Cats; Cattle; Cell Death; Cell Line; Culture Techniques; Dose-Response Relationship, Drug; Fluorescent Antibody Technique, Indirect; Haplorhini; Lactoferrin; Poliomyelitis; Poliovirus; Virulence