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History

Progress in production technology, as well as in pharmacological understanding, will allow continued development of human proteins as an important therapeutic option in a variety of human diseases.

From a biochemical view point, there is an interesting diversity within these proteins in their primary protein structure (chain of amino acids) compared to the naturally occurring human form(s) and their post-translational modifications (including the natural process of glycosylation, the addition of sugar groups to specific amino acids, and the artificial process of PEGylation, the addition of PEG groups to amino acids).

Initially, biochemical differences between the therapeutic proteins and their natural counterparts often reflected either technical or biological limitations.

Technological challenges may relate to a specific production platform (e.g., bacterial versus mammalian cell system), and to the complexity of the human protein, for example in terms of the presence or absence of glycosylation, or to the number of genes involved in the synthesis.

The first expression platform established was Escherichia coli, which came with a large body of knowledge on the genetics, simple cultivation requirements and a short generation time.This platform worked well for insulin and human growth hormone. But soon it was realized that E. coli had one serious shortcoming: it was unable to modify proteins by glycosylation. This was not a problem for producing insulin and human growth hormone since these proteins do not undergo glycosylation in their natural human form. Problems were, however, anticipated for many other recombinant proteins with therapeutic value, since most of the human extracellular proteins (and even some intracellular proteins) are naturally modified with sugar chains.

Glycosylation of proteins is a highly complex post-translational modification process taking place in the endoplasmic reticulum and Golgi apparatus and involving more than a hundred different proteins (and genes). This glycosylation machinery is absent in E. coli, present but different from mammalian cells in the yeast Saccharomyces cerevisiae, but highly conserved among mammalian cells (e.g., human, Chinese hamster).

Although the yeast S. cerevisiae expresses Nglycosylation sites encoded by human genes, its glycosylation pattern is so different from that of humans.

Use of three mammalian cell lines,derived from Chinese hamster ovary (CHO) cells, baby hamster cells (BHK) cells, or human fibrosarcoma cells, elegantly provided the necessary glycosylation in the production of many other therapeutically intended naturally glycosylated proteins.

If glycosylation is required, then normally mammalian expression platforms are favorable, such as CHO or BHK cells. Lately, attempts have been made to modify other platforms like S. cerevisiae or plants by metabolic engineering such modified organisms are capable of introducing human-like sugar moieties

Thus, a goal of a therapeutic protein being as identical as possible to the human counterpart is a common misconception.

 

Our Activites

1) Recombinant subunit vaccines are some of the most safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for production and administration make them impractical for many developing world diseases.

2) One major hurdle preventing these therapies from reaching the market has been the lack of a suitable production platform that allows the cost-effective production of these highly complex molecules.

 

About Microalgae

Green microalgae have proven to be highly useful protein production platform for therapeutic protein production , while vaccine antigens have been transformed into many edible species and use as oral formulation for vaccine 

Algae have been shown to accumulate and properly fold several vaccine antigens, and effective orally delivered vaccines

The chloroplast of microalgae provide a unique enclosed compartment that facilitate folding , unlike prokaryotes chloroplasts of algae contain much of the same sophisticated cellular folding machinery as other eukaryotic organism like yeast   

The chloroplast of the green alga Chlamydomonas reinhardtii has been shown to contain the machinery necessary to fold and assemble complex eukaryotic proteins. However, the translational apparatus of chloroplasts resembles to a eukaryotic host.