Recombinant porcine lactoferrin expressed in the milk of transgenic mice protects neonatal mice from a lethal challenge with enterovirus type 71.

The human Enterovirus genus of the piconavirus family causes most of the febrile illnesses that affect children during the summer season in Taiwan. Enterovirus type 71 (EV71) plays a key role in patients with hand-foot-and-mouth disease (HFMD) combined with severe paralysis or encephalitis. It is important to find a method for preventing infection with EV71 since there is no antiviral agent or vaccine for humans. In this study, we developed a transgenic mouse model for demonstrating the protective effects of recombinant lactoferrin (LF) against EV71 infection. Transgenic mice carrying alpha-lactalbumin-porcine lactoferrin (alphaLA-pLF) and BALB/c wild-type mice were subjected to EV71 inoculation. First, we analyzed the expression efficiencies of recombinant pLF (rpLF) in hemizygous and homozygous transgenic mice. Following EV71 inoculation on the 4th day of life, pups ingesting transgenic milk showed the significantly higher survival rate and heavier body weight compared to wild-type mice. RT-PCR analysis for EV71 viral RNA showed that the recombinant pLF had a blocking effect on EV71 infection. Our data suggest that oral intake of pLF-enriched milk exhibited the ability to prevent infection with EV71. The study also provides an animal model for validating the protective effects of pLF.