Process for producing exogenous protein in the milk of transgenic mammals and a process for purifying proteins therefrom

Abstract

The invention relates to a method of producing a protein of interest, comprising making a non-human transgenic mammal that produces said protein in its milk, obtaining said milk from the non-human transgenic mammal and purifying said protein of interest from the milk. Transgenic bovine animals were generated, which are able to produce human growth hormone in mammary glands. The method involves cloning of a genetic construct encoding hGH gene and beta casein promoter conveniently in an expression vector. It also includes transfection procedures into fetal bovine somatic cells, generally fibroblasts, and the nuclear transfer into enucleated bovine oocytes, generating thus transgenic embryos. The method also includes other procedures to generate transgenic embryos for the further expansion of the transgenic herd, such as the subcloning of transgenic female bovines, the superovulation of transgenic cows and their insemination with semen from a non-transgenic or a transgenic male bovine, and the superovulation of non-transgenic cows and their insemination with semen from a transgenic male bovine. Afterwards, transgenic embryos give rise to transgenic cattle that produce human growth hormone in huge amounts in their milk, from which the hormone is completely purified and analysed to fulfill all the requirements for the manufacture of a pure biopharmaceutical product.

Description

BACKGROUND OF THE INVENTION [0001] Protein factors and hormones involved in human health care have been currently produced by pharmaceutical industry by extraction or by recombinant technology in the last decades. Expression of genetic constructs involving the desired genes were successfully expressed in bacteria, yeast or mammalian cell lines. However, the use of mammalian cell cultures to obtain complex proteins, such as those which require a proper glycosylation pattern, involves high cost procedures. [0002] Recombinant DNA technology has been used increasingly over the past decade for the production of commercially important biological materials. To this end, the DNA sequences encoding a variety of medically important human proteins have been cloned. These include insulin, plasminogen activator, alpha1-antitrypsin and coagulation factors VIII and IX. At present, even with the emergent recombinant DNA techniques, these proteins are usually purified from blood and tissue, an expen...

AI Technical Summary

Problems solved by technology

However, the use of mammalian cell cultures to obtain complex proteins, such as those which require a proper glycosylation pattern, involves high cost procedures.

At present, even with the emergent recombinant DNA techniques, these proteins are usually purified from blood and tissue, an expensive and time consuming process which may carry the risk of transmitting infectious agents such as those causing AIDS and hepatitis.

Although the expression of DNA sequences in bacteria to produce the desired medically important protein looks an attractive proposition, in practice the bacteria often prove unsatisfactory as hosts because in the bacterial cell foreign proteins are unstable and are not processed correctly.

However, batch fermentation of animal cells is an expensive and technically demanding process.

However, nuclei in S phase at the time of the transfer show a characteristic “pulverized” appearance; PCC produces extensive DNA damage.

However, there is no report of polar body formation after NT into enucleated MII oocytes in cattle, sheep or pigs, suggesting differences between species in the mechanics controlling formation of intact spindles and extrusion of polar bodies.

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