Immunotherapeutic targeting of established sarcoma in Swiss mice by tumor-derived antigen-pulsed NLGP matured dendritic cells is CD8+ T-cell dependent

Abstract

Aim: Neem leaf glycoprotein (NLGP) matures human myeloid and mouse bone marrow-derived dendritic cells (DCs). (NLGP) also therapeutically restricts the mouse established sarcoma growth by activating CD8+ T cells along with increased proportion of tumor residing CD11c+ DCs. Here, we intended to find out whether CD8+ T cells become cytotoxic to sarcoma cells after presentation of sarcoma antigen by NLGP-matured DCs to restrict murine sarcoma growth. Materials & methods: NLGP was prepared from matured neem(Azadirachta indica) leaves. Solid sarcoma tumor in Swiss mice was developed by subcutaneous inoculation of sarcoma cells. GMCSF-IL-4 generated DCs were matured with NLGP and pulsed with sarcoma antigen for immunotherapy. Status of CD8+CD69+T cells was studied by flow cytometry and secretion of cytokines was measured by ELISA. RT-PCR was used to monitor the status of perforin, granzyme B. Results: NLGP-matured sarcoma antigen-pulsed DCs (DCNLGPTAg) inhibit mouse sarcoma growth. DCNLGPTAg immunization enhances CD8+ T-cell number within tumor-infiltrating lymphocytes and tumor-draining lymph nodes along with increased perforin and granzyme B expression. Antigen-specific T-cell proliferation and IFN-γ secretion were significantly higher in DCNLGP- and DCNLGPTAg-immunized mice groups. In vivo CD8+ T-cell depletion abrogated the DCNLGPTAg-mediated tumor growth restriction. Conclusion: DCNLGPTAg restricts CD8+ T-cell-dependent mouse established sarcoma growth, related to the optimum antigen presentation by DCs to CD8+ T cells.