Scientists design mouse with more human-like immune response

Medical scientists at the University of Southern California (USC) have bred a first-of-its-kind mouse model that possesses an immune response system more like a human's. The discovery makes way for quicker and more cost-effective development of next-generation drugs to treat human diseases like cancer, diabetes and tuberculosis.

Medical researchers have long used mice and rats to help formulate new drugs and vaccines, in part because their genetic and biological characteristics closely parallel human physiology. But mice are not humans, and many experimental drugs that work extraordinarily well in rodents fail miserably when tested in people.

One such drug, a-galactosylceramide (a-GalCer), essentially wipes out cancerous tumours in mice by activating the body's immune system; for reasons not entirely clear, the drug does not trigger the same response in people with cancer.

Scientists hypothesise that the failure to translate is due to subtle differences between the CD1d molecules in mice and humans and how they respond to tumours and infection.

CD1d molecules are found on certain cells that trigger the body's innate immune response.

In a study to be published by the Proceedings of the National Academy of Sciences the week of 4 Februaury, USC researchers describe how they genetically engineered mice to express CD1d molecules that look more like those in humans and in more similar proportions. More importantly, the humanised CD1d molecules effectively trigger natural killer T (NKT) cells -- a recently discovered type of white blood cell that attacks tumors and infection -- in live animals when exposed to a-GalCer.