Subunit antigen expression

Tab. 9.2 Vaccine antigens expressed in plant systems subunit antigen expression in transgenics... 

Figure 10. Tissue specific expression of p-subunit proteins in floral tissues. Stage 3 (fully opened) flowers were collected, dissected and cell wall proteins (5 pgm) from the indicated organs isolated and analyzed for p-subunit antigen. Note the high level of expression in stigma/style and anthers/pollen and restriction of the larger antigen to stigma/style tissues. PGl lane, 1 gg of purified fruit PGl protein.

Porcilis pesti (vaccine containing Intervet r classical swine fever virus E2 subunit antigen, produced in an insect cell baculovirus expression system)... 

Subunit vaccines based on the surface proteins of vims are also being explored. It has been demonstrated that the two major protective antigens are haemagglutinin (HA) and neuraminidase (NA). The genes for these antigens have been cloned and expressed in baculovims in insect cell culture (84). 

Expression of Potential Vaccine Antigens. In general, in the future, eukaryotic cell culture is likely to be the method of choice for the production of subunit vaccine antigens where the organism to be vaccinated against replicates in eukaryotic cells. E. coli are unable to posttranslationally modify some vaccine candidates for example, bacterial systems cannot add carbohydrate which is important in the antigenicity and structure of many protective antigens. 

Peterson, S. R., D. M. Gadbois, E. M. Bradbury, and P. M. Kraemer. 1995. Immortalization of human fibroblasts by SV40 large T antigen results in the reduction of cyclin D1 expression and subunit association with proliferating cell nuclear antigen and Wafl. Cancer Res 55(20) 4651-7. 

R.H. Vonderheide, W.C. Hahn, J.L. Schuitze, and L.M. Nadier, The telomerase catal34ic subunit is a wideiy expressed tumor associated antigen recognized by cytotoxic T lymphocytes. Immunity 10, 673-679 (1999). 

The first system used to produce vaccines was potato plants and transgenic tubers have being employed in some clinical trials. Expression of vaccines is also reported in other hosts such as tomato, banana, carrot, lettuce, maize, alfalfa, white clover and Arabidospis. Hepatitis B surface antigen was successfully expressed in cherry tomatillo and potato. Expression of human cholera toxin p subunit was achieved in tomato and tobacco plants. ... 

A number of B. pertussis (polypeptide) antigens have been expressed in E. coli and other recombinant systems. Several of these are being evaluated as potential subunit vaccines, including B. pertussis surface antigen, adhesion molecules and pertussis toxin. Pertussis toxin has been shown to protect mice from both aerosol and intracerebral challenge with virulent B. pertussis. The bacterial proteins that mediate surface adhesion protect mice from aerosol but not intracerebral challenge. Future pertussis subunit vaccines may well contain a combination of two or more pathogen-derived polypeptides. 

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