Recombinant C-type lectin protein of Toxocara canis increases the population of spleen Foxp3+ regulatory T cells in BALB/c mice.

Toxocara canis (T. canis) is a common parasitic nematode in dogs and cats. Parasitic worms can cause chronic and long-term infections in their host, due to their ability to neutralize the host's defense mechanisms. They can stimulate immune response-mediated regulatory T (T-reg) cells. The aim of this study is to evaluate the effect of recombinant T. canis C-type lectin protein (TCTL-1) on cell infiltration in the brains of BALB /c mice as well as the number of regulatory T cells. Six-week-old female BALB/c mice received the recombinant C-type lectin protein of T. canis six times intravenously and intraperitoneally. Twenty-eight days after the first injection, the spleen and brain of mice were removed under sterile conditions. The brains of mice were examined by histopathological staining methods. The FOXP3+ regulatory T cell population was determined by flow cytometry. The cell populations of regulatory T cells in spleen mononuclear cell culture of 3 female BALB/c mice injected with recombinant TCTL-1 (group I) were 2.59%, 1.64%, and 1.78 and in spleen mononuclear cell culture of three female BALB/c mice injected with sterile PBS (group II) as a control group were 1.14%, 1.13%, and 1.15%. Also, no cell infiltration was seen around the cerebral arteries of mice receiving this protein. This recombinant protein would increase the population of FOXP3+ regulatory T cells. These results suggest that recombinant C-type lectin protein of T. canis can modulate immune responses, reduce severe inflammatory responses, and induce FOXP3+ regulatory T cells.

A review on targeting tumor microenvironment: The main paradigm shift in the mAb-based immunotherapy of solid tumors.

Monoclonal antibodies (mAbs) as biological macromolecules have been remarked the large and growing pipline of the pharmaceutical market and also the most promising tool in modern medicine for cancer therapy. These therapeutic entities, which consist of whole mAbs, armed mAbs (i.e., antibody-toxin conjugates, antibody-drug conjugates, and antibody-radionuclide conjugates), and antibody fragments, mostly target tumor cells. However, due to intrinsic heterogeneity of cancer diseases, tumor cells targeting mAb have been encountered with difficulties in their unpredictable efficacy as well as variability in remission and durable clinical benefits among cancer patients. To address these pitfalls, the area has undergone two major evolutions with the intent of minimizing anti-drug responses and addressing limitations experienced with tumor cell-targeted therapies. As a novel hallmark of cancer, the tumor microenvironment (TME) is becoming the great importance of attention to develop innovative strategies based on therapeutic mAbs. Here, we underscore innovative strategies targeting TME by mAbs which destroy tumor cells indirectly through targeting vasculature system (e.g., anti-angiogenesis), immune system modulation (i.e., stimulation, suppression, and depletion), the targeting and blocking of stroma-based growth signals (e.g., cancer-associated fibroblasts), and targeting cancer stem cells, as well as, their effector mechanisms, clinical uses, and relevant mechanisms of resistance.

Investigation of antitumor effects of Lactobacillus crispatus in experimental model of breast cancer in BALB/c mice.

AIM: To evaluate the effect of intraperitoneal injections of heat-killed Lactobacillus crispatus on breast tumor size and overall survival of Balb/c mouse received 4T1 mammary carcinoma. Materials and methods: Different doses of L. crispatus have been injected intraperitoneally in BALB/c mice. RESULTS: Tumor size was decreased in the experiment group treated with 1 × 108 bacteria/200 µl. Treatment with 1 × 108 bacteria/200 µl resulted in survival improvement. The myeloid-derived suppressor cells and reactive oxygen species production have been increased in all groups. Cox2 expression decreased in tumor tissues of the mice treated with 108 bacteria/200 µl. The expressions of Arginase and iNos increased in the spleen and tumor tissues of those treated with 5 × 108 bacteria/200 µl. CONCLUSION: We have shown the protective effect of L. crispatus on survival of tumor-bearing mice.