Porcine lactoferrin administration enhances peripheral lymphocyte proliferation and assists infectious bursal disease vaccination in native chickens.

The purpose of this study was to investigate the effects of dietary supplementation with recombinant porcine lactoferrin (rPLF) produced by yeast culture on peripheral lymphocyte proliferation and serum antibody titers in chickens vaccinated against the infectious bursal disease (IBD) virus. Treatment groups were fed with rPLF powder in their diet (2.0%, w/w), and the IBD vaccine was administrated at 1 and 3 weeks of age. At 8, 12, and 16 weeks after vaccination, serum IBD antibody titers were measured via the micro-method and T cell proliferation rates were evaluated. In gene expression analyses, rPLF-treated chicken peripheral T lymphocytes were stimulated with concanavalin A (ConA) for 24h. The mRNA expression levels of interleukin-2 (IL-2), interferon-gamma (IFN-gamma), interleukin-4 (IL-4), and interleukin-12 (IL-12) were determined using a semi-quantitative RT-PCR assay. The results revealed that the rPLF additive led to significant increases in serum IgG and IBD-specific antibody titers (P<0.05). The rPLF administration significantly increased chicken intestinal villous lengths and also enhanced the expression of IFN-gamma and IL-12 in chicken T lymphocytes. These data suggest that rPLF enhances cell-mediated immunity and augment the ability of IBD vaccination to benefit chicken industry in disease resistance.

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.

Recombinant porcine lactoferrin expressed in the milk of transgenic mice enhances offspring growth performance.

The European Commission has proposed a permanent ban on the use of antibiotics as an ingredient in animal feed to promote growth. Lactoferrin is a globular multifunctional protein that has been shown to play a role in iron absorption and to have antimicrobial and anti-inflammatory activities. Therefore, lactoferrin may serve as a nontherapeutic alternative to antibiotics in livestock husbandry. As a pilot study toward this goal, transgenic mice have been generated harboring a porcine lactoferrin (pLF) gene driven by the mammary gland-specific promoter of the bovine alpha-lactalbumin (alphaLA) gene. The alphaLA-pLF hybrid gene was confirmed to have been successfully integrated and transmitted stably through the germ-line in 9 (5 females and 4 males) of 14 transgenic founders. In the female progenies of six lines analyzed, the transgene copy numbers ranged from 1 to 20 with 1-4 integration sites. Significant levels of pLF protein in milk ranging from 40 to 106 microg/mL with physical characteristics similar to those of native pLF in sow's milk were achieved in three of the transgenic lines obtained. Tissue- and stage-specific pLF expressions were restricted to the mammary gland of the transgenic female mice during lactation. It was further demonstrated that the growth performance of animal pups is enhanced by directly feeding the genetically engineered milk containing enriched pLF protein in transgenic mice. Furthermore, this enhanced growth performance in suckling mice was proportional to the concentration of pLF present in milk.