The therapeutic effect of mesenchymal stem cells (MSC) has been extensively investigated in recent decades, however this therapeutic effect has not been fully characterised. The aim of this study is to elucidate the inhibitory effect of MSC on haematopoietic tumour cells proliferation such as BV173 cell line. To this end, MSC generated from bone marrow, after immunophenotyping, they were co-cultured with tumour cell. The result shows that MSC profoundly inhibit the tumour cell proliferation via arresting the tumour cells at G0 and G1 phase of cell cycle.

Classically, MSC are identified by a CD45-CD106+ phenotype. In this study, we found that mouse MSC achieve this characteristic phenotype only at later passages. With increasing passages, CD45 (hematopoietic marker) expression shifts to negativity, whereas CD106 (vascular cell adhesion molecule-1) expression becomes increasingly positive. These results demonstrate that MSC cells cultured from mouse bone marrow acquire a classical MSC immunophenotype (CD45-CD106+) in later passages.

The immune modulatory properties of mesenchymal stem cell (MSC) had brought a new insight in cell-based neotherapy. However, recent works of MSC are focused exclusively on bone marrow-derived MSC. We evaluated the immunogenicity of cord blood-derived MSC (CB-MSC) on T lymphocytes. Human peripheral blood mononuclear cells (PBMC) were prepared by density gradient separation and culture with the presence or absence of CB-MSC. PBMC were collected for activation analysis by flow cytometry at 24-, 48-, and 72- hours. The results showed that, CB-MSC does not stimulate nor inhibit T lymphocyte activation.

Mesenchymal stem cells (MSC) are common residents of bone marrow and are defined by their higher self-renewal ability and multilineage differentiation. MSC play an important role in supporting haematopoiesis and therefore are implicated in influencing immune responses. In line with this, MSC have been utilized to treat graft-versus-host disease (GVHD) in order to suppress unwanted T cell proliferation. In this study, we investigated the immune-suppressive effect of bone marrow derived MSC on T cell proliferation at the cell cycle level. MSC were generated from human bone marrow and confirmed by their immune-phenotyping. Resting or PHA stimulated allogeneic peripheral blood mononuclear cells (PBMC) were co- cultured in the presence or absence of MSC. T cell proliferation was accessed by trypan-blue exclusion assay at day three. Consequently cell cycle analysis was carried out to determine the mechanism of antiproliferation. MSC failed to elicit proliferation at resting T cell. However, proliferation of PHA-stimulated T cells was dramatically inhibited in the presence of MSC in a dose dependent manner (p<0.05). Following the inhibitory activity, MSC prevented activated T cells from entering the S phase of cell cycle by arresting them in the G1 phase. Our findings indicate that MSC escape recognition by T cells and inhibit T cell proliferation by cell cycle arrest at G1 phase. This immune-suppressive effect is most probably mediated by cell-to-cell contact and/or secreted soluble factors.
T-Lymphocytes ; Cell Cycle ; seconds ; Law enforcement arrest ; Stem Cells

Aims: To develop a real-time polymerase chain reaction system Vi-qPCR in the detection of Salmonella enterica serovar Typhi (S. Typhi), targeting the vexC gene encoding for Vi antigen (capsular polysaccharide antigen) and to evaluate its sensitivity and specificity performance using pure cultures of S. Typhi and other enteric pathogens. Methodology and results: Microbiological, biochemical and serotyping tests were conducted to determine the phenotypic characteristics of S. Typhi and other enteric pathogens in our collection. Primers were designed using Primer3 software and their in-silico specificity were analysed using Basic Local Alignment System Tool (BLAST). Optimisation of PCR annealing temperature was done prior to assessment of sensitivity and specificity performance against artificial serially diluted seeded stools. The primers were found to be 100% specific in the detection of S. Typhi towards 32 tested clinical strains. Verification of gene amplification by comparing the nucleotide sequences against reference genes in the GenBank database revealed high specificity to S. Typhi. Statistical analysis indicates that this method results in 100% sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Moreover, Vi-qPCR allows the detection of S. Typhi as low as 131.4 CFU/g of stool sample. Conclusion, significance and impact of study A rapid and sensitive method for detection of Salmonella enterica serovar Typhi (S. Typhi) is desired as a diagnostic tool to improve typhoid management. The Vi-qPCR represent a promising non-invasive diagnostic tool for medical microbiology laboratories as a method for the detection of S. Typhi in both pure culture and stool specimens especially in chronic asymptomatic carriers where shedding of S. Typhi is intermittent and sometimes occurs in low level.