[The immunoregulatory functions of exosome derived from mesenchymal stem cells that are genetically modified by adeno-associated virus]

Objectives: To verify the effects and mechanisms of natural MSC-exosome in treating acute GVHD in mice, explore and establish a method for targeted modification of MSC-exosome, and verify the functions of the modified MSC-exosome. Methods: In different doses of MSC-exosome groups and MSC group, weight loss in acute GVHD mice was observed; then the proliferation levels of activated T cells were measured through T cell activation experiment in vitro and OVA antigen-specific T cell activation experiment in vivo. AAV2YF3 mutants carrying PD-L1 and PD-L1-ITGB1 were obtained after the construction of recombinant expression vectors and were then applied to infect human MSC to modify their exosome. The immunoregulatory functions of the modified MSC-exosome were measured with the abovementioned methods. Results: ①Mouse MSC-exosome (300 μg×3 times) and MSC (1×10(6)×3 times) effectively alleviated the weight loss in acute GVHD mice. ②Compared with IL-2, 10, 25 and 50 μg human MSC-exosome inhibited the proliferation of activated T cells in vitro, respectively, 86.0% (IL-2) , 40.0%, 39.6%, and 42.8%; compared with PBS, 50, 100 and 200 μg mouse MSC-exosome inhibited the proliferation of antigen-specific activated OT-1 cells in vivo, respectively, 42.6%, 33.1%, 14.2%, and 10.6%. ③After the infection of AAV2YF3 mutant carrying PD-L1 or PD-L1-ITGB1, the positive proportion of MSC-exosome exceeds 40% and 60%, respectively. ④Compared with the natural state, MSC-exosome modified by PD-L1 or PD-L1-ITGB1 showed better proliferation inhibitory effect in vivo and increased the proportion of Treg cells in vitro. Conclusions: MSC-exosome exhibited similar immunomodulatory effects with MSC. MSC-exosome after PD-L1 and PD-L1-ITGB1-targeted modification effectively inhibited the proliferation of activated T cells and increased the proportion of Treg cells.

[Tumor derived IgG suppress the proliferation of T cells in cord blood]

OBJECTIVE

To explore the function of tumor derived IgG (tIgG) and whether the tIgG can inhibit T cells activity.

METHODS

The tIgG was purified from ovarian cancer tissue. The cord blood monocyte cells (CBMC) and cord blood lymphocyte (CBL) were isolate from human umbilical cord blood. The CBMC and CBL were stimulated with phytohaemagg lutinin (PHA) in order to let the CBMC and CBL in the state of proliferation. Carboxyfluorescein succinimidyl amino ester (CFSE) was cultured with CBMC and CBL. CFSE had no cell toxicity, which could penetrate through the cell membrane and combine the intracellular protein. The fluorescence intensity decreased with the proliferation of cells step by step, so the proliferation of these cells could be detected in flow ctytometry. The tIgG which was purified from ovarian cancer tissue was divided into three groups, 1 mg/L group, 10 mg/L group, and 100 mg/L group, and the intravenous immunoglobulin (IVIG) was also divided into three groups too. The CBMC and CBL were treated by tIgG with 1 mg/L, 10 mg/L, and 100 mg/L in order to observe the proliferation of T cells. The cells were treated with IVIG as a positive control group, and the cells were treated with phosphate buffer saline (PBS) as a negative control. The proliferation of CD4⁺ or CD8⁺ T cells were detected in CBMC and CBL. The proliferation of the T cells in CBMC and CBL after 64 h and 86 h were detected.

RESULTS

In the system of CBMC, the tIgG could suppress the proliferation of CD4⁺ or CD8⁺ T cells. The results could also be found in the system of CBL. The CD4⁺ or CD8⁺ T cells in the group which were treated with PBS were more active than those in the group which were treated with tIgG and IVIG. The suppression in the group which were treated with tIgG, was stronger than that in the group treated with IVIG. In addition, the suppression of T cells in the group which were stimulated with tIgG as 100 mg/L was more effective than that in the group which were stimulated with tIgG as 10 mg/L. This could prove that tIgG had the function of immunomodulation.

CONCLUSION

The tIgG can be involved in immune escape of cancer.

Characterization of microsatellite loci in the lesser dawn bat (Eonycteris spelaea)

We constructed a genomic DNA library enriched for CA repeat motifs in Eonycteris spelaea. Nine microsatellite loci were isolated and tested on a population of 39 samples from Yunnan Province, China. These nine loci had three to 22 alleles per locus. Observed and expected heterozygosity values ranged from 0.079 to 0.963 and from 0.078 to 0.959. Two loci revealed significant departure from Hardy-Weinberg equilibrium and no linkage disequilibrium was found between loci pairs. These microsatellites can be a powerful molecular tool for population-level studies of E. spelaea.

Livin and caspase-3 expression are negatively correlated in cervical squamous cell cancer

OBJECTIVE

Overexpression in cancer cells of inhibitor of apoptosis proteins like livin appears to promote tumorigenesis by regulating expression of proteins involved in apoptosis signaling. Here, the authors investigated expression of livin and an apoptosis protein that is known to inhibit, caspase-3, in cervical squamous cell carcinoma.

MATERIALS AND METHODS

Their expression was assessed for correlation with tumor invasiveness. Immunohistochemistry for livin and caspase-3 was used in 36 normal cervical tissues and in 98 samples of cervical squamous cell carcinoma. The percentage of cells expressing these proteins was compared between normal and cancer samples. Their expression rates in cancer samples were subsequently compared with one another and with the clinical and pathological characteristics of the samples.

RESULTS

Livin was more commonly expressed in tumor samples than in normal tissues, while the opposite pattern was observed for caspase-3. Expression of livin was significantly associated with advanced clinical stage, higher pathological grade, and lymph node metastasis (p < 0.05). Expression of caspase-3 was significantly associated with lower clinical stage, lower pathological grade, and lack of lymph node metastasis (p < 0.05). Finally, expression of livin was negatively correlated to caspase-3 expression in cervical squamous cell carcinoma tissue (r = -0.57, p < 0.05).

CONCLUSIONS

Livin may inhibit apoptosis in cervical squamous cell carcinoma by downregulating caspase-3, thereby promoting disease progression.