Cervical cancer is one of the most common cancers in developing
countries and the second most prevalent cancer in women. Almost all
cervical cancers result from human papillomavirus (HPV) infection.
Although vaccines against the virus, based on virus-like particles
rather on attenuated HPV, have recently been made available, their high
cost prohibits their widespread use especially in developing countries.
In search of ways that will make HPV vaccine production cheaper,
scientists from Spain and France developed transgenic tobacco lines
expressing the HPV protein L1. L1 is a major structural protein in the
viral capsid (protein shell) that aggregates to form non-infectious
virus-like particles (VLP). Since it can induce both humoral and
cellular responses, VLPs are prime candidates in the production of HPV
vaccines.

The viral gene coding for L1 was specifically expressed in the
chloroplasts. Chloroplast transformation offers several advantages such
as transgene containment, absence of gene silencing and high recombinant
protein yield. High L1 expression, equivalent to 24 percent of the total
soluble protein, was achieved in mature GM plants. Immunization
experiments have shown that the recombinant protein and the resulting
VLPs are highly immunogenic.

The article published by the Plant Biotechnology Journal is available at

[www.blackwell-synergy.com]