ABSTRACT
Although numbers of naked antibodies showing clinical efficacy as single agents, their therapeutic effect is limited. Chemotherapy is very effective but with relatively large side effects, so conjugation of small chemotherapeutic drugs to antibodies is one of the important methods to enhance therapeutic potential of antibodies. Antibody-drug conjugates (ADCs) represent a promising therapeutic approach for cancer patients by combining the antigen-targeting specificity of monoclonal antibodies (mAbs) with the cytotoxic potency of chemotherapeutic drugs. These modified antibodies are expected to selectively deliver chemotherapeutic drugs to tumor cells and provide sustained clinical benefit to cancer patients, at the same time, minimizing systemic toxicity. ADCs are expected to bring together the benefits of highly potent drugs on the one hand and selective binders of specific tumor antigens on the other hand. However, designing an ADC is very complex, requiring thoughtful combination of antibody, linker, and payload drugs in the context of a target and a defined cancer indication. Although many challenges remain, recent clinical success has generated intense interest in this therapeutic class.
ABSTRACT
<p><b>OBJECTIVE</b>To understand the biochemical characteristics, virulence genes and pathogenicity of Shigella flexneri Xv isolated in Beijing.</p><p><b>METHODS</b>61 strains of S. flexneri Xv isolated from diarrhea patients in Beijing were systematically determined through biochemical reactions and serological tests. Application of PCR technique in detection of virulence genes on ipaH, sen, virF, ial and pulsed-field gel electrophoresis (PFGE) was used to identify the related characteristics and on rat lung slices to determine its pathogenicity.</p><p><b>RESULTS</b>All of the S. flexneri Xv could ferment glucose, mannitol, melibiose and arabinose. Using serum agglutination, we found that the antigen structure was (IV: 7, 8). IpaH, sen, virF and ial that carried rates of virulence genes appeared to be 100%, 81.97%, 75.41% and 80.30%, respectively. Among 61 strains of S. flexneri Xv, the PFGE typing of Shigella bacteria could be divided into 25 belt types while the results from rat lung slices showed inflammatory change of Xv.</p><p><b>CONCLUSION</b>S. flexneri Xv was found that it carried high rate of Shigella virulence genes, exhibiting genetic polymorphism and highly invasive.</p>
Subject(s)
Animals , Humans , Rats , Microbial Sensitivity Tests , Shigella flexneri , Classification , Virulence , Virulence , GeneticsABSTRACT
Multilocus sequence typing (MLST) is a molecular genotyping method based on nucleotide sequencing. The procedure of this method characterizes isolates of bacterial species using the DNA sequencing of multiple housekeeping genes(usually seven). For each housekeeping gene, the different sequences present within a bacterial species are assigned as distinct alleles.For each isolate, the alleles at each of the loci define the allelic profile or sequence type (ST). MLST has the advantages of being robust (based on genetic data) and electronically portable to generate data that allow rapid and global comparisons between different laboratories. In this paper, the principle, method, data analysis, application, advantages and flaws of MLST are introduced.
ABSTRACT
Construction of mutant strain is an essential method in pathogenesis researches. The conventional method for Brucella unmarked deletion mutant construction is based on suicide plasmid, but the efficiency is very low. In the present study, we first optimized the electroporation parameters, and then, the cloning plasmid pEX18Gm containing sacB was successfully used to construct unmarked deletion mutant of the type IV secretion system. This indicated that by using conventional cloning plasmid as suicide plasmid in Brucella, unmarked deletion mutants can be constructed with high efficiency.