Immunoenhancing properties of the anti-tumor effects of adoptively transferred T cells with chemotherapeutic cyclophosphamide by co-administration of bone marrow cells

In this study we aimed to determine the anti-tumor efficacy of co-treatment of adoptively transferred T cells with bone marrow either harvested from naïve mice or G-CSF activated after treatment with the anti-cancer drug cyclophosphamide (CTX) as a source enriched in stem cells. CTX-treated Swiss Albino (CD-1) mice were injected with 2 × 105 Ehrlich ascetic carcinoma (EAC) cell line and then adoptively transferred with in vitro co-activated T cells with or without bone marrow one day post CTX treatment. All mice were vaccinated with tumor lysate and Hiltonol®. The results showed that co-transfer of activated T cells with bone marrow provided the highest antitumor effect and induced marked increase in numbers of splenocytes, leucocytes and bone marrow cells. Interestingly, T cells derived from EAC tumor-bearing host induced higher effects than those from normal mice. In sum, our data suggest that combination of CTX and activated transferred T cells with bone marrow induces proliferation and expansion of immune cells, which are functional and can be exploited in vivo to foster more effective antitumor adoptive immunotherapy strategies.