LONDON - Pharming Group NV, of Leiden, the Netherlands, said it has succeeded in generating the first transgenic female calves using nuclear transfer. The company did not identify which transgene the two calves are carrying, but said they are the first of a herd, due to be born this year, which will produce one of its lead biopharmaceuticals in their milk.
The program to generate the transgenic herd was begun in February 1998, in collaboration with Infigen Inc., of DeForest, Wis. A parallel nuclear transfer program, in which no transgenes were used, has so far resulted in the production of 10 cows. All of the animals, the first of which was born at Infigen's facility in November 1998, were said to be healthy.
The announcement of the births was made last week by Pharming CEO George Hersbach at the Successful Commercialization of Transgenic Animal Proteins conference in San Diego. The company now intends to use nuclear transfer to generate production herds for several of its biopharmaceuticals. The technique produces herds much faster than breeding a herd from a single transgenic founder generated by microinjection. It also makes it possible to determine the sex of the animal, ensuring that only females are produced.
To generate the transgenic calves, the desired gene was introduced into cultured female bovine cells of fetal origin. Cells that took up the transgene were isolated, and their nuclei fused to cow oocytes (eggs) from which the nucleus had been removed. The resulting transgenic embryos were then implanted in the wombs of foster mothers and carried to term.
To accommodate all the transgenic calves due to be born this year, Pharming has begun construction of a new farm in DeForest.