Natalia Pogrebnyak

Smallpox subunit vaccine produced in planta confers protection in mice

We report here the in planta production of the recombinant vaccinia virus B5 antigenic domain (pB5), an attractive component of a subunit vaccine against smallpox. The antigenic domain was expressed by using efficient transient and constitutive plant expression systems and tested by various immunization routes in two animal models. Whereas oral administration in mice or the minipig with collard-derived insoluble pB5 did not generate an anti-B5 immune response, intranasal administration of soluble pB5 led to a rise of B5-specific immunoglobulins, and parenteral immunization led to a strong anti-B5 immune response in both mice and the minipig. Mice immunized i.m. with pB5 generated an antibody response that reduced virus spread in vitro and conferred protection from challenge with a lethal dose of vaccinia virus. These results indicate the feasibility of producing safe and inexpensive subunit vaccines by using plant production systems.

Development and phytochemical characterization of high polyphenol red lettuce with anti-diabetic properties.

Polyphenol-rich Rutgers Scarlet Lettuce (RSL) (Lactuca sativa L.) was developed through somaclonal variation and selection in tissue culture. RSL may contain among the highest reported contents of polyphenols and antioxidants in the category of common fruits and vegetables (95.6 mg/g dry weight and 8.7 mg/g fresh weight gallic acid equivalents and 2721 µmol/g dry weight and 223 µmol/g fresh weight Trolox equivalents). Three main compounds accumulate at particularly high levels in RSL: chlorogenic acid, up to 27.6 mg/g dry weight, cyanidin malonyl-glucoside, up to 20.5 mg/g dry weight, and quercetin malonyl-glucoside, up to 35.7 mg/g dry weight. Major polyphenolic constituents of RSL have been associated with health promotion as well as anti-diabetic and/or anti-inflammatory activities. Daily oral administration of RSL (100 or 300 mg/kg) for up to eight days acutely reduced hyperglycemia and improved insulin sensitivity in high fat diet-induced obese hyperglycemic mice compared to vehicle (water) control. Data presented here support possible use of RSL as a functional food for the dietary management of diabetes.

Plant-produced hepatitis B core protein chimera carrying anthrax protective antigen domain-4.

The hepatitis B core antigen (HBcAg) can generate a strong immune response and is recognized as an effective carrier for foreign epitopes. The domain-4 epitope of the anthrax protective antigen (PA-D4) plays an essential role in generating protective immunity against virulent Bacillus anthracis. Here we report the successful production of a recombinant protein comprised of the antigenic PA-D4 integrated into the c/e1 loop of HBcAg in transgenic low-alkaloid Nicotiana tabacum. Sera of mice injected with the plant-derived purified HB/PA-D4 protein exhibited significant anti-PA- and anti-HBcAg-specific IgG titers; however, formation of virus-like particles (VLP) was not observed. These data support the feasibility of producing complex protein chimeras in plants.