Suppressed Innate Immune Response against Mammary Carcinoma in BALB/C Mice
Abstract
Breast carcinoma is one of the leading causes of deaths among women worldwide. Immune response in breast cancer is mediated by the innate and adaptive immune cells including natural killer (NK) cells, dendritic cells (DCs) and T lymphocytes. 4T1 mammary carcinoma derived from BALB/c mice shares many characteristics with naturally occurring human breast cancer. We aimed to investigate the mechanisms of anti-tumor immunity using the experimental 4T1 breast cancer model in syngeneic BALB/c mice. After 12 days of tumor inoculation, mammary carcinoma-bearing mice had significantly decreased numbers of NKp46+ NK cells compared to healthy mice and lower cytotoxic activity of total splenocytes and NK cells in vitro. Also, significantly higher numbers of CD11c+ DCs were detected in spleens of tumor bearing mice, but the numbers of activated CD80+CD86+ dendritic cells did not differ compared to healthy mice, indicating an increased number of immature DCs in tumor-bearing mice. The data indicate that 4T1 mammary carcinoma progression in BALB/c mice is associated with suppressed innate anti-tumor immunity.