Immunochromatography detection of human lactoferrin protein in milk from transgenic cattle

Transgenic technologies have opened a new era of transgenesis, characterized by manipulating intraspecies or interspecies genes in microorganisms, plants, or animals to change them in desired directions. The advent of genetically modified animals and related products has raised the need for analytical methods, nucleotide- or protein-based, to qualitatively and quantitatively determine the biotechnology ingredients. In this study, we collected milk samples containing human lactoferrin (hLF) protein, to exploit appropriate detection means for exogenous hLF protein. We preliminarily developed two types of competitive immunochromatography strips for quick detection, based on gold-conjugated hLF protein or gold-conjugated polyclonal antibody. As control methods, sodium dodecyl sulfate polyacrylamide gel electrophoresis, dot blot, and Western blot methods were used to check the accuracy of strips, and highly sensitive ELISA with chemiluminescent substrates was developed to determine the concentration of hLF in milk. Comparing the test results of lateral flow strips with qualitative assays, we found our strips gave the same results in a few minutes, showing great advantages with no need of professional technicians or any equipment. Our results demonstrated that all the applied methods were effective to detect hLF, suggesting that they could be used to monitor the production of transgenic milk.