Pilot testing of a sampling methodology for assessing seed attachment propensity and transport rate in a soil matrix carried on boot soles and bike tires

Land managers of natural areas are under pressure to balance demands for increased recreation access with protection of the natural resource. Unintended dispersal of seeds by visitors to natural areas has high potential for weedy plant invasions, with initial seed attachment an important step in the dispersal process. Although walking and mountain biking are popular nature-based recreation activities there are few studies quantifying propensity for seed attachment and transport rate on boot soles and none for bike tires. Attachment and transport rate can potentially be affected by a wide range of factors for which field testing can be time-consuming and expensive. We pilot tested a sampling methodology for measuring seed attachment and transport rate in a soil matrix carried on boot soles and bike tires traversing a known quantity and density of a seed analog (beads) over different distances and soil conditions. We found % attachment rate on boot soles was much lower overall than previously reported but that boot soles had a higher propensity for seed attachment than bike tires in almost all conditions. We believe our methodology offers a cost-effective option for researchers seeking to manipulate and test effects of different influencing factors on these two dispersal vectors

Plant viral genes in DNA idiotypic vaccines activate linked CD4+ T-cell mediated immunity against B-cell malignancies

DNA delivery of tumor antigens can activate specific immune attack on cancer cells. However, antigens may be weak, and immune capacity can be compromised. Fusion of genes encoding activating sequences to the tumor antigen sequence facilitates promotion and manipulation of effector pathways. Idiotypic determinants of B-cell tumors, encoded by the variable region genes, are clone-specific tumor antigens. When assembled as single-chain Fv (scFv) alone in a DNA vaccine, immunogenicity is low. Previously, we found that fusion of a sequence from tetanus toxin (fragment C; FrC) promoted anti-idiotypic protection against lymphoma and myeloma. We have now investigated an alternative fusion gene derived from a plant virus, potato virus X coat protein, a primary antigen in humans. When fused to scFv, the self-aggregating protein generates protection against lymphoma and myeloma. In contrast to scFv?FrC, protection against lymphoma is mediated by CD4+ T cells, as is protection against myeloma. Plant viral proteins offer new opportunities to activate immunity against linked T-cell epitopes to attack cancer

DNA vaccines to target the cancer testis antigen PASD1 in human multiple myeloma

We previously described PASD1 as a new cancer testis antigen in multiple myeloma (MM) that is retained post-therapy, suggesting the use of vaccination strategies to induce anti-PASD1 immunity in a setting of minimal residual disease. We have focused on DNA fusion gene vaccines, coupling fragment C domain (DOM) of tetanus toxin with PASD1 sequence, and examined efficacy in Human Leukocyte Antigen (HLA)-A2 (HHD) transgenic mice using a human MM cell line expressing PASD1 protein and chimeric HLA-A2 class I molecules as target. DNA vaccines encoded two HLA-A2-restricted epitopes (p.DOM-PASD1(1), p.DOM-PASD1(2)) and full-length PASD1 (p.DOM-PASD1FL). p.DOM-PASD1(1) proved superior to p.DOM-PASD1(2) in generating T-cell responses in HHD mice, able to lyse the chimeric murine RMA-HHD cells. Boosting by electroporation significantly enhanced p.DOM-PASD1(1). Only p.DOM-PASD1(1) induced cytotoxic T-lymphocytes (CTLs) were able to lyse human MM target cells expressing endogenous antigen. The p.DOM-PASD1FL vaccine predominantly induced strong PASD1(1) over PASD1(2) T-cell immune responses, indicative of immunodominance. Importantly, p.DOM-PASD1FL generated immune-mediating killing of native chimeric MM cells, in the absence of exogenous added peptide, implicating PASD1(1) specific CTLs. These data demonstrate that PASD1-derived epitopes are both efficiently and selectively processed and presented by native human MM cells. Notably, they permit the use of PASD1-encoding DNA vaccine therapy in a clinical setting

Letter. PML-RARA-targeted DNA vaccine induces protective immunity in a mouse model of leukemia

Despite improved molecular characterization of malignancies and development of targeted therapies, acute leukemia is not curable and few patients survive more than 10 years after diagnosis. Recently, combinations of different therapeutic strategies (based on mechanisms of apoptosis, differentiation and cytotoxicity) have significantly increased survival. To further improve outcome, we studied the potential efficacy of boosting the patient's immune response using specific immunotherapy. In an animal model of acute promyelocytic leukemia, we developed a DNA-based vaccine by fusing the human promyelocytic leukemia?retinoic acid receptor-alpha (PML-RARA) oncogene to tetanus fragment C (FrC) sequences. We show for the first time that a DNA vaccine specifically targeted to an oncoprotein can have a pronounced effect on survival, both alone and when combined with all-trans retinoic acid (ATRA). The survival advantage is concomitant with time-dependent antibody production and an increase in interferon-bold gamma (IFN-bold gamma). We also show that ATRA therapy on its own triggers an immune response in this model. When DNA vaccination and conventional ATRA therapy are combined, they induce protective immune responses against leukemia progression in mice and may provide a new approach to improve clinical outcome in human leukemia