High Level Expression of Active Human Alpha-1-Antitrypsin in the Milk of Transgenic Sheep

Abstract

We describe the generation of five sheep transgenic for a fusion of the ovine beta-lactoglobulin gene promotor to the human alpha 1-antitrypsin (h alpha 1AT) genomic sequences. Four of these animals are female and one male. Analysis of the expression of h alpha 1AT in the milk of three of these females shows that all express the human protein at levels greater than 1 gram per liter. In one case initial levels exceeded 60 grams per liter and stabilized at approximately 35 grams per liter as lactation progressed. Human alpha 1AT purified from the milk of these animals appears to be fully N-glycosylated and has a biological activity indistinguishable from human plasma-derived material.

Construction and functional study of pGN, a mammary gland-specific expression plasmid

“…To improve milk production, the key factor for transgenic expression lies in the selection of a lactation-related gene and an optimal regulatory element. Recent studies have shown that high level expressions in mammary glands of rats (Lee et al, 1996), sheep (Wright et al, 1991), goats (Parker et al, 2004), and cows (van Berkel et al, 2002) could be obtained by b-lactoglobulin and b-casein regulation. Production ability of ruminant mammary glands is generally determined based on the number and activity of secreted cells.…”

Genetic Modification of Domestic Animals for Agriculture and Biomedical Applications

“…Transgenic goats, capable of synthesizing human butyrylcholinesterase (Huang et al, 2007) and human longer acting tissue plasminogen activator (Ebert et al, 1991) in their milk have also been created. Human salmon calcitonin in milk of transgenic rabbits (McKee et al, 1998); human factor IX and alpha-1-antitrypsin (Wright et al, 1991) in milk of transgenic sheep; and human lactoferrin (van Berkel et al, 2002;Yang et al, 2008), human growth hormone (Salamone et al, 2006) and human -lactalbumin in milk of transgenic cows are all additional examples of using transgenic domestic animals and the mammary gland as a bioreactor for production of recombinant proteins. Table 2 summarizes some recombinant proteins expressed in milk or blood of cloned transgenic domestic animals.…”

Lung Diseases - Selected State of the Art Reviews

“…A topical gel formulation of r-α 1 -PI has been intended for the treatment of dermatitis and other severe dermatological disorders in phase II clinical trials (see Brown, 2006b). The second example of the advanced development of recombinant human α 1 -PI is large scale production performed in transgenic dairy animals (t-α 1 -PI): sheep [by PPL Therapeutics (UK) in partnership with Bayer Biologicals (USA), (Dalrymple & Garner, 1998;Wright et al, 1991)], and goats [by Genzyme Transgenics Corporation (USA), (Ziomek, 1998)]. The transgenic α 1 -PI recovered from sheep milk was purified to 99.9% purity.…”