Diagnosis of active tuberculosis using MPB64, a specific antigen of Mycobacterium bovis.

Because the incidence of tuberculosis (TB) is still high in developing countries, an inexpensive and rapid diagnostic test for this infection is needed. To develop a screening test for TB, MPB64 antigen was produced by recombinant technology and purified with a polyhistidine tag. Next, serum and urine samples from patients with TB and uninfected individuals were examined by the dot-blot assay method using this purified antigen. Serum samples from patients with TB reacted more strongly with MPB64 antigen than did those from uninfected individuals. In addition, serum samples from TB patients with active infection reacted more strongly with the antigen than did samples from patients with inactive TB. When urine samples were assessed using this assay, similar results were obtained. Correlations between the data obtained from serum and urine samples were analyzed for all subjects, including uninfected individuals, and a strong positive correlation between the results of serum and urine tests (n = 36, r = 0.672) was found. The sensitivity and specificity of this assay for serum samples was 85.7 % and 85.0 %, and for urine samples 75.0 % and 85.0 %, respectively. These results suggest that dot-blot assay with MPB64 antigen could be a useful screening test for active TB. Because urine samples can be obtained more easily than serum samples and because urine is less contagious, urine testing should probably be employed for screening purposes.

Shared expression of mucin12 in Ascaris lumbricoides and the human small intestine.

This study focuses on the host-parasite relationship of human Ascaris lumbricoides, which is a parasite of the small intestine and is also one of the commonest parasites worldwide. As part of this investigation, we examined the host-parasite relationship assuming that there is a common antigenicity, shared protein between A. lumbricoides and human small intestinal mucosa, using molecular techniques. We obtained three DNA clones from human colon cDNA library by screening for anti-A. lumbricoides polyclonal antibodies. The transmembrane mucin12 gene was identified after sequencing analysis of these clones. Specific signals of immunostaining with polyclonal anti-mucin12 antibodies were observed in the mucous secretory organs, epidermis, and intestinal canal of A. lumbricoides. These signals disappeared when immunohistochemistry was performed using pre-absorbed polyclonal antibodies with a specific peptide. These results suggest that mucin12 is localized in the mucous secretory organs in the epidermis of A. lumbricoides. Furthermore, we examined the site of mucin12 localization in the host; specific mucin12 signals were observed on the mucosal epithelia present around intestinal crypts and villi of the small intestine. Therefore, we suggest that mucin12 is a protein that shows common antigenicity in both A. lumbricoides and its host. It is presumed that adult A. lumbricoides live in their preferred environment, which is the small intestine, by secreting mucin12 to avoid being attacked by the host immune system.

Over-expression of bHLH genes facilitate neural formation of mouse embryonic stem (ES) cells in vitro.

Mouse embryonic stem (ES) cells are useful tools for investigating differentiation into neurons and glial cells in vitro. In order to induce ES cells to differentiate into neural cells, many researchers have investigated the efficiency of induction. Embryoid body (EB) formation and retinoic acid are potent differentiation inducers known to be a trigger at the early stage of development. Basic helix-loop-helix (bHLH) is one of the important transcription factors, which is essential for premature neural formation. In NeuroD2 and Mash1-transfected cells, neural formation was observed at day 6 after the plating of embryoid bodies in culture. Nestin was detected in NeuroD2- and Mash1-transfected cells at day 10, and strong signal was detected in Mash1 transfectants by RT-PCR analysis. Map2 and Nurr1 were also detected strongly at the early stage in transfected cells compared with the wild type control, especially in the Mash1 transfectant. In immunocytochemical analysis, Tuj1-positive neurons were detected at high frequency in Mash1 transfectants and some cells were stained by tyrosine hydrogenase (TH), a marker of dopaminergic neurons. These results demonstrate that bHLH has a potential activity at an early stage for ES cells and can induce effective and rapid neural differentiation in vitro.