Abstract

Despite the steady increase of hygienic standards, the CDC continues to report an increase of immune-mediated diseases such as allergies and asthma. Human avoidance of microbial exposure and subsequently less experienced immune systems may be the cause for this increase. We investigated if increased microbial exposure results in increased immunity to cancer (B16 melanoma) by measuring activated lymphocytes between two groups of C57Bl/6 mice: specific pathogen free (SPF) mice (which had little microbial exposure) and cohoused (COH) mice (which were exposed to numerous microbes). Previous research shows that the CoH mouse model mimics a human adult’s immune system, while the SPF mouse model mimics that of a human infant’s. Activated lymphocyte levels were quantified with weekly bleeds using antibody staining flow cytometry. Anti-tumor response was evaluated through multiple harvests in which blood, lymph nodes, spleens, and tumors were collected and analyzed with flow cytometry. CoH mice were expected to have heightened levels of activated lymphocytes and an anti-tumor response superior to the SPF mice. The CoH mice did gain microbial experience and showed in a higher quantity of activated CD8+ T cells. Preliminary results suggest that this may have resulted in an increased anti-tumor response and slowed cancer proliferation.