Lactoferrin and Its Digestive Fragments Boost Antiviral Immune Responses by Activating Dendritic Cells

Peripheral blood mononuclear cells (PBMCs) were isolated from healthy adult donors and incubated with bovine lactoferrin, its pepsin hydrolysate (LFH), or lactoferricin (LFcin) in the presence or absence of single-stranded RNA derived from HIV. IFN-α concentrations were measured by ELISA, and expression of IFN-α, HLA-DR, and CD86 on plasmacytoid dendritic cells was quantified by flow cytometry.

Lactoferrin is a naturally occurring protein in milk and other body fluids that has long been studied for antimicrobial and immune-modulating properties. This study provides a specific mechanism for how lactoferrin and its digestive fragments enhance antiviral immunity — by activating plasmacytoid dendritic cells, which are critical first responders to viral infections. The fact that digested fragments retain activity is particularly important because it suggests orally consumed lactoferrin could provide immune benefits.

Lactoferrin is one of the most extensively studied bioactive peptide sources, available as a dietary supplement and found naturally in breast milk, saliva, and tears. Understanding exactly how it enhances immune function — through pDC activation and IFN-α amplification — adds mechanistic depth to the growing body of evidence supporting its role in innate immunity. This work is particularly relevant in the context of viral pandemic preparedness, where safe, accessible immune-supporting compounds could serve as adjuncts to vaccines and antivirals.

This is an ex vivo study using isolated human blood cells in a laboratory setting — results may not directly predict what happens when lactoferrin is consumed orally and passes through the full digestive and circulatory systems. The number of blood donors was not specified in the abstract. Only one type of viral stimulus (HIV-derived ssRNA) was tested, so generalizability to other viral infections is uncertain.