Assessment of Carrot Callus as Biofactories of an Atherosclerosis Oral Vaccine Prototype

Atherosclerosis is a pathology leading to cardiovascular diseases with high epidemiologic impact; thus, new therapies are required to fight this global health issue. Immunotherapy is a feasible approach to treat atherosclerosis and given that genetically engineered plants are attractive hosts for vaccine development; we previously proved that the plant cell is able to synthesize a chimeric protein called CTB:p210:CETPe, which is composed of the cholera toxin B subunit (CTB) as immunogenic carrier and target epitopes from the cholesteryl ester transfer protein (CETP_461–476) and apolipoprotein B100 (p210). Since CTB:p210:CETPe was expressed in tobacco at sufficient levels to evoke humoral responses in mice, its expression in carrot was explored in the present study looking to develop a vaccine in a safe host amenable for oral delivery; avoiding the purification requirement. Carrot cell lines expressing CTB:p210:CETPe were developed, showing accumulation levels up to 6.1 µg/g dry weight. An immunoblot analysis revealed that the carrot-made protein is antigenic and an oral mice immunization scheme led to evidence on the immunogenic activity of this protein; revealing its capability of inducing serum IgG responses against p210 and CETP epitopes. This study represents a step forward in the development of an attractive oral low-cost vaccine to treat atherosclerosis.     

Expression of an HBcAg-based antigen carrying angiotensin II in Chlamydomonas reinhardtii as a candidate hypertension vaccine

In contrast to traditional pharmacological treatments for hypertension, immunotherapies serve as promising alternatives as they are low-cost and afford better patient compliance. In this study, a chimeric protein targeting Angiotensin II via genetic fusion to a nucleocapsid antigen from Hepatitis B virus (HBcAg), serving as a carrier, is designed. This candidate immunogen designated as HBcAgII has been expressed in the alga specie Chlamydomonas reinhardtii, serving as an attractive vaccine expression system and delivery host. This alga can be grown on minimal media under controlled environmental conditions, and can serve as a safe oral delivery vehicle. Transgenic C. reinhardtii lines have been developed, and the expected recombinant protein has been detected by Western blot and ELISA analyses. Levels of expression of this recombinant protein in some transgenic lines have reached 0.05 % of total soluble protein. The immunogenic properties of the HBcAgII algae-derived antigen will be assessed.     

Arsenic removal using Chlamydomonas reinhardtii modified with the gene acr3 and enhancement of its performance by decreasing phosphate in the growing media

Abstract

Arsenic contamination of groundwater is a significant problem in countries like Mexico, where San Luis Potosi is among the regions registering severe levels of it. Bioremediation with microalgae capable to absorb and metabolize metals or metalloids like arsenic reduces their toxicity and is a cost-effective approach compared to physical–chemical processes. We evaluated the capability of Chlamydomonas reinhardtii to remove arsenate and compared it with an acr3-modified recombinant strain, which we produced by transforming the wild-type strain with Agrobacterium tumefaciens using the construct pARR1 including a synthetic, optimized acr3 gene from Pteris vittata, a hyper-accumulator of arsenic. We monitored the growth of both strains in media with arsenate, containing a standard or a 10-fold decreased amount of phosphate. Comparing both strains in media initially with 0.5, 1, and 1.5?mg/L of arsenate, the acr3-modified strain removed 1.5 to 3 times more arsenic than the wild-type strain. Moreover, the arsenic uptake rate increased 1.2 to 2.3 times when growing the acr3-modified strain in media with decreased phosphate, while the uptake rate for the wild-type strain scarcely changed under the same conditions. These results confirm the expression of the acr3 gene in C. reinhardtii and its potential application to remove arsenic.