Preparation, characterization and epitope mapping of monoclonal antibodies specific to human mast cell carboxypeptidase

Immunoaffinity purification of α-momorcharin from bitter melon seeds (Momordica charantia)

α-Momorcharin (α-MMC), a type I ribosome-inactivating protein (RIP), has shown therapeutic potential such as anti-tumor and anti-viral agent. Traditional process of α-MMC purification from bitter melon seeds was time consuming and low efficient. To take this challenge, we made an affinity matrix by coupling the monoclonal antibody (McAb) with Sepharose 4B. Using this attractive strategy, 196 mg of α-MMC was obtained from 100 g of bitter melon seeds as the starting material. The yield of the protein was 2.7%. The homogeneity and properties of the protein were assessed by SDS-PAGE, acidic PAGE, RP-HPLC and N-terminal sequence as well as Western blot. Purified α-MMC showed remarkable inhibition to the melanoma cell line JAR and EMT-62058. In addition, it also displayed obvious inhibition on hepatitis B virus (HBV). This work provided a simple, rapid and efficient approach for α-MMC purification from Momordica charantia.

Preparation and characterization of a monoclonal antibody with high affinity for soluble Abeta oligomers

Amyloid beta-protein (Abeta) has been causally implicated in the neurodegenerative processes that accompany Alzheimer's disease. Soluble oligomers of the Abeta(1-42) fragment are thought to be significantly more neurotoxic than higher molecular weight aggregates. We report the isolation and characterization of a mouse monoclonal antibody (MAb) directed against soluble Abeta(1-42) oligomers. Synthetic Abeta(1-42) oligomers were assembled in vitro; these were used to immunize mice, and hybridomas were isolated following myeloma fusion of splenocytes from immunized animals. Screening for reactivity against Abeta(1-42) resulted in the identification of MAb A8 with high affinity for soluble oligomers. The isotype of A8 was found to be IgG(2b). Experiments using sub-peptides of Abeta(1-42) revealed that the epitope identified by A8 lies within the 1-6 region of Abeta. The antibody displays high affinity for soluble Abeta(1-42) oligomers in the molecular weight range of 16.5-25 kDa, and detected target antigen in brain sections from senescence-accelerated SAMP 8 mice. The sensitivity and optimal titers for the detection of soluble Abeta(1-42) oligomers were determined to be 0.625 microg/mL in indirect ELISA, and 1:10(6), 1:4000, and 1:150 for ELISA, Western blotting, and immunohistochemistry, respectively. The A8 antibody specific for soluble Abeta(1-42) oligomers will provide a valuable tool for Alzheimer's disease research.