A Bicistronic DNA Vaccine Containing Apical Membrane Antigen 1 and Merozoite Surface Protein 4/5 Can Prime Humoral and Cellular Immune Responses and Partially Protect Mice against VirulentPlasmodium chabaudi adamiDS Malaria

Abstract

The ultimate malaria vaccine will require the delivery of multiple antigens from different stages of the complex malaria life cycle. In order to efficiently deliver multiple antigens with use of DNA vaccine technology, new antigen delivery systems must be assessed. This study utilized a bicistronic vector construct, containing an internal ribosome entry site, expressing a combination of malarial candidate antigens: merozoite surface protein 4/5 (MSP4/5) (fused to a monocyte chemotactic protein 3 chemoattractant sequence) and apical membrane antigen 1 (AMA-1) (fused to a tissue plasminogen activator secretion signal). Transfection of COS 7 cells with bicistronic plasmids resulted in production and secretion of both AMA-1 and MSP4/5 in vitro. Vaccination of BALB/c mice via intraepidermal gene gun and intramuscular routes against AMA-1 and MSP4/5 resulted in antibody production and significant in vitro proliferation of splenocytes stimulated by both AMA-1 and MSP4/5. Survival of BALB/c mice vaccinated with bicistronic constructs after lethal Plasmodium chabaudi adami DS erythrocytic-stage challenge was variable, although significant increases in survival and reductions in peak parasitemia were observed in several challenge trials when the vaccine was delivered by the intramuscular route. This study using a murine model demonstrates that the delivery of malarial antigens via bicistronic vectors is feasible. Further experimentation with bicistronic delivery systems is required for the optimization and refinement of DNA vaccines to effectively prime protective immune responses against malaria.

Coexpression of 16.8 kDa antigen of Mycobacterium avium paratuberculosis and murine gamma interferon in a bicistronic vector and studies on its potential as DNA vaccine

“…A similar size of IFN was reported earlier (Grey and Goddel 1983). The time of expression by pIRES vector was similar as reported by other workers (Rainczuk et al 2004) who expressed malarial proteins in pIRES transfected COS7 cells and recovered expressed proteins after 48 h.…”

Predicting Antidisease Immunity Using Proteome Arrays and Sera from Children Naturally Exposed to Malaria

“…In a recent cross-sectional study in malaria-exposed individuals in the Brazilian Amazon (80), plasma from asymptomatic individuals reacted more strongly to recombinant MSP4 protein than those from symptomatic cases, but anti-MSP4 antibodies could not be independently associated with asymptomatic status. However, polyclonal antisera raised in rabbits inhibited the growth of asexual P. falciparum parasites in vitro, and in rodent models, MSP4 recombinant protein plus adjuvant (81)(82)(83) and MSP4 DNA vaccines (84,85) provided partial protection against blood stage challenge.…”

Nonviral Vectors for Cancer Gene Therapy: Prospects for Integrating Vectors and Combination Therapies

“…Following PMT-based administration of plasmid DNA, transgene expression can be detected in blood and tumor tissue of treated mice (Sun et al 1995). Although PMT has not achieved a level of gene transfer that is superior to viral vectors, it has proven to be very useful to deliver DNA vaccines to the skin and to tumors, in some cases leading to induction of anti-tumor immunity (Bartholdy et al 2004;Hahn et al 2004;Rainczuk et al 2004;Tanaka et al 2004;Tree et al 2004;Wang et al 2004). Thus, PMT may become a viable method for delivering DNA vaccines clinically and shows promise for cancer gene therapy (Trimble et al 2003).…”