Effect of Climate Conditions and Plant Developmental Stage on the Stability of Antibodies Expressed in Transgenic Tobacco

Abstract

Plants are regarded as a promising system for the production of heterologous proteins. However, little is known about the influence of plant physiology and plant development on the yield and quality of the heterologous proteins produced in plants. To investigate this, tobacco (Nicotiana tabacum cv Samsun NN) was transformed with a single construct that contained behind constitutive promotors the light- and heavy-chain genes of a mouse antibody. The in planta stability of the antibody was analyzed in transgenic plants that were grown under high and low irradiation at 15 degrees C and 25 degrees C. High-light conditions favored the production of biomass, of total soluble protein, and of antibody. The plants grown at 25 degrees C developed faster and contained less antibody per amount of leaf tissue than the plants grown at 15 degrees C. Both endogenous protein and antibody content showed a strong decline during leaf development. The heavy chains of the antibody underwent in planta degradation via relatively stable fragments. In vitro incubations of purified plantibody with leaf extracts of wild-type tobacco indicated the involvement of acidic proteases. It is interesting that the same antibody produced by mouse hybridoma cells exhibited higher stability in this in vitro assay. This may be explained by the assumption that the plant type of N-glycosylation contributes less to the stability of the antibody than the mouse-type of N-glycosylation. The results of this study indicate that proteolytic degradation during plant development can be an important factor affecting yield and homogeneity of heterologous protein produced by transgenic plants.

Problems of Reproducibility and Efficacy of Bioassays Using Crude Extracts, with reference to Aloe vera

“…[29] Furthermore, the phytochemical profiles of individual plants will change, dependent on a variety of other environmental and growth conditions. [6,7] Plants may produce a wide variety of secondary metabolites which have no apparent role in primary plant growth or development processes. These molecules are often unique to plants from a single species and increase during times of high stress such as drought, fire and bacterial infection.…”

“…Plants grown under varied conditions will often produce different phytochemical profiles, or at least different quantities of the individual components. [6,7] Similarly, different cultivars within a …”

High Stability of Recombinant Proteins Expressed in Tobacco Chloroplasts

“…Protein yield is the net result of synthesis and degradation [23], thus protein stability is as important as synthesis. Therefore, increasing the half-life of a recombinant protein in the chloroplast could be one mechanism for increasing the yield of foreign proteins expressed in plants.…”

Plant Bioreactors for Pharmaceuticals

“…One of the major obstacles in the plant bioreactor is the low yield of recombinant proteins (de Wilde et al, 2007;Ma et al, 2003;Twyman et al, 2003), which are susceptible to proteolytic degradation in transgenic plant cells (De Neve et al, 1993;Doran, 2006;Stevens et al, 2000). Therefore, reducing protease activity in transgenic plants is one of the potential approaches to improve the yield of recombinant proteins.…”