ABSTRACT
OBJECTIVE: The aim of this is to compare the immunotherapeutic effects of human colorectal cancer antigen GA733-2 fused to the Fc fragment of antibody (GA733-2-Fc) and to Fc and endoplasmic reticulum (ER) retention motif KDEL (GA733-2-Fc-KDEL). MATERIALS AND METHODS: Recombinant GA733-2-Fc and GA733-2-Fc-KDEL were produced from infiltrated Nicotiana benthamiana leaves and purified by affinity chromatography. Glycan structures were determined by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. The allergic and immunogenic responses of recombinant GA733-2-Fc and GA733-2-Fc-KDEL were estimated in an intraperitoneally immunized mouse. The tumor regression effect of recombinant GA733-2-Fc and GA733-2-Fc-KDEL was examined using a colorectal carcinoma CT-26 animal model. RESULTS: Recombinant GA733-2-Fc contained plant-specific glycan structures including ß(1,2)-xylose and α(1,3)-fucose whereas recombinant GA733-2-Fc-KDEL contained oligomannose type glycan structures. Mice immunized intraperitoneally with recombinant GA733-2-Fc and GA733-2-Fc-KDEL elicited strong GA733-2-Fc-specific immunoglobulin G (IgG) and IgA serum antibody responses. Recombinant GA733-2-Fc-KDEL reduced the production of GA733-2-Fc-specific IgE. Recombinant GA733-2-Fc-KDEL increased the production of interferon-γ. Intraperitoneal preimmunization with recombinant GA733-2-Fc and GA733-2-Fc-KDEL regressed tumor growth in a colorectal carcinoma CT-26 animal model. The tumor regression effect induced by recombinant GA733-2-Fc-KDEL was greater than that induced by recombinant GA733-2-Fc. The human and mouse colorectal carcinoma cell binding activities of recombinant GA733-2-Fc-KDEL-immunized sera were higher than those of recombinant GA733-2-Fc. CONCLUSIONS: Our results suggest that GA733-2-Fc conjugated to ER-retention motif KDEL is a more efficient antigen to prevent tumor growth induced by colorectal carcinoma and minimize an allergic response.
Subject(s)
Colorectal Neoplasms/genetics , Epithelial Cell Adhesion Molecule/pharmacology , Oligopeptides/pharmacology , Polysaccharides/pharmacology , Animals , Antibodies, Monoclonal , Cell Adhesion Molecules/chemistry , Cell Adhesion Molecules/genetics , Cell Line, Tumor , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/pathology , Endoplasmic Reticulum/chemistry , Epithelial Cell Adhesion Molecule/chemistry , Epithelial Cell Adhesion Molecule/genetics , Humans , Immunoconjugates/genetics , Immunoconjugates/pharmacology , Immunoglobulin E/genetics , Immunoglobulin E/pharmacology , Immunoglobulin Fc Fragments/chemistry , Immunoglobulin Fc Fragments/pharmacology , Mice , Oligopeptides/genetics , Polysaccharides/chemistry , Protein Sorting Signals/genetics , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/pharmacologyABSTRACT
Pseudomonas syringae pv. actinidiae (Psa) causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs) originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant antibacterial activity by only the liquid culture assay, while cinnamaldehyde exhibited antibacterial activity by both assays. The minimum inhibitory concentrations (MICs) of estragole and cinnamaldehyde by the liquid culture assay were 1,250 and 2,500 ppm, respectively. The MIC of cinnamaldehyde by the vapor diffusion assay was 5,000 ppm. Based on the formation of clear zones or the decrease of optical density caused by these compounds, they might kill the bacterial cells and this feature might be useful for managing the bacterial canker disease in kiwifruit.
