Combination therapy with dendritic cell-based vaccine and anti-CD69 antibody enhances antitumor efficacy in renal cell carcinoma-bearing mice.

BACKGROUND/AIM: Dendritic cell-based vaccine therapy for renal cell carcinoma is effective but requires improvement. Here we explored whether combination therapy with dendritic cell-based vaccine and anti-CD69 antibody can enhance antitumor efficacy in renal cell carcinoma-bearing mice. MATERIALS AND METHODS: Balb/c mice were challenged subcutaneously with murine renal cell carcinoma (Renca) cells. On day 3 after tumor cell inoculation, tumor-bearing mice either were left untreated or were treated with Renca tumor lysate-pulsed dendritic cells (i.e. dendritic cell-based vaccine), anti-CD69 antibody, or a combination of Renca tumor lysate-pulsed dendritic cells with anti-CD69 antibody. The mice were sacrificed on day 28. Tumor volume was measured for analysis of antitumor efficacy. Spleens were excised to evaluate antitumor immunological responses by measuring the proliferation and activation of T cells, which have the capacity to recognize and destroy tumor cells. RESULTS: Combination treatment with Renca tumor lysate-pulsed dendritic cells and anti-CD69 antibody resulted in significant decreases in tumor volume and significant increases in T-cell proliferation and activity, compared with no treatment or either treatment alone. CONCLUSION: These findings indicate that anti-CD69 antibody can potentiate antitumor efficacy of dendritic cell-based vaccine. The augmented therapeutic efficacy conferred by the combination therapy may be associated with increased T-cell proliferation and activity.

Anti-CD27 Antibody Potentiates Antitumor Effect of Dendritic Cell-Based Vaccine in Prostate Cancer-Bearing Mice.

In the current study, we investigated whether anti-CD27 monoclonal antibody can enhance the antitumor efficacy of a dendritic cell-based vaccine in prostate cancer-bearing mice. The overall therapeutic effect of a dendritic cell-based vaccine for prostate cancer remains moderate. A prostate cancer model was established by subcutaneous injection of RM-1 tumor cells into male C57BL/6 mice on day 0. After 4 days, tumor-bearing mice were treated with RM-1 tumor lysate-pulsed dendritic cells (i.e., dendritic cell-based vaccine), anti-CD27 monoclonal antibody, or a combination of RM-1 tumor lysate-pulsed dendritic cells with anti-CD27 monoclonal antibody. Mice were killed at 21 days after tumor cell implantation. Tumor size was measured for assessment of antitumor effect. Spleens were collected for analysis of antitumor immune responses. The antitumor immune responses were evaluated by measuring the proliferation and activity of T cells, which have the ability to kill tumor cells. The combination therapy with RM-1 tumor lysate-pulsed dendritic cells and anti-CD27 antibody significantly enhanced T-cell proliferation and activity, and significantly reduced tumor growth, compared with monotherapy with RM-1 tumor lysate-pulsed dendritic cells or anti-CD27 antibody. Our results suggest that combined treatment can strengthen antitumor efficacy by improving T-cell proliferation and activity.

Arachnoid cell involvement in the mechanism of coagulation-initiated inflammation in the subarachnoid space after subarachnoid hemorrhage.

OBJECTIVE: To assess if arachnoid cells have the capability to present antigen and activate T-lymphocytes after stimulation by bloody cerebrospinal fluid (CSF), and to illuminate the mechanism of coagulation-initiated inflammation in the subarachnoid space after subarachnoid hemorrhage (SAH). METHODS: Arachnoid cells were cultured, characterized, and examined by immunofluorescence for the basal expression of human leukocyte antigen-DR (HLA-DR). Expression of HLA-DR, after co-culturing arachnoid cells in vitro with bloody CSF, was investigated by immunofluorescence and flow cytometry (FCM). The variation of arachnoid cells' ultrastructure was observed by transmission electron microscope (TEM). Arachnoid cells were co-cultured with peripheral blood mononuclear cells (PBMCs). The content of soluble interleukin-2 receptor (sIL-2r) in culture medium was detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: (1) Arachnoid cells were successfully cultured for many passages. The immunofluorescent staining was positive for HLA-DR in over 95% of the human arachnoid cells. The punctate HLA-DR was distributed in cytoplasm and not in the karyon. (2) After co-culturing arachnoid cells in vitro with bloody CSF, numerous particles with strong fluorescence appeared in the cytoplasm on Day 6. On Day 8, the quantity of particles and fluorescent intensity were maximal. FCM showed that the percentage of HLA-DR expressing cells was (2.5+/-0.4)% at the first 5 d, increasing to (60.8+/-3.6)% on Day 7. (3) After co-culturing arachnoid cells in vitro with bloody CSF, many lysosome and secondary lysosome particles were present in the cytoplasm. Hyperplasia of rough endoplasmic reticulum and enlarged cysts were observed, with numerous phagocytizing vesicles also observed at the edge of the arachnoid cells. (4) Arachnoid cells stimulated by bloody CSF were co-cultured in vitro with PBMCs. The content of sIL-2r in the culture medium, having been maintained at around 1.30 ng/ml during the first 3 d, had increased by Day 4. The content of sIL-2r peaked 7.53 ng/ml on Day 7 and then reduced gradually. CONCLUSIONS: (1) Basic HLA-DR expression is present in arachnoid cells. (2) After stimulation by bloody CSF, arachnoid cells have the potential to serve as antigen presenting cells (APCs) and the ability to activate T-lymphocytes, indicating that arachnoid cells are involved in the mechanism of coagulation-initiated inflammation in the subarachnoid space after SAH.

Intracerebral xenotransplantation of semipermeable membrane- encapsuled pancreatic islets.

AIM: To identify the decreasing effect of xenotransplantion in combination with privileged sites on rejection and death of biological semipermeable membrane-(BSM) encapsulated implanted islets. METHODS: After the BSM experiment in vitro, BSM-encapsulated SD rat's islet-like cell clusters (ICCs) were xenotransplanted into normal dog's brain. Morphological changes were observed under light and transmission electron microscope. The islets and apoptosis of implanted B cells were identified by insulin-TUNEL double staining. RESULTS: The BSM used in our study had a favorable permeability, some degree of rigidity, lighter foreign body reaction and toxicity. The grafts consisted of epithelioid cells and loose connective tissue. Severe infiltration of inflammatory cells was not observed. The implanted ICCs were identified 2 mo later and showed typical apoptosis. CONCLUSION: BSM xenotransplantation in combination with the privileged site can inhibit the rejection of implanted heterogeneous ICCs, and death of implanted heterogeneous B cells is associated with apoptosis.