Figure 7
CD11b+Gr-1+cells in mock treated and HV-68 infected mice with metastatic breast cancer suppressed anti-CD3-induced T cell activation. Groups of mice were mock treated (white bars) or HV-68 infected (black bars). Six months post-infection, mice were injected with syngeneic 4 T1 mammary tumor cells in the mammary fat pad. At day 44 following tumor cell transplantation, groups of mice were euthanized and CD11b+Gr-1+cells were isolated from spleens of individual mice. The indicated numbers of CD11b+Gr-1+cells were added to 2 × 105 cultured T lymphocytes stimulated with anti-CD3 antibodies. After 72 hours of co-incubation, culture supernatants were assayed for interferon gamma (IFN-γ) production as a measure of T cell activation. Results are presented as means (N = 4) ± standard errors with asterisks indicating a statistically significant difference (p < 0.05) as numbers of CD11b+Gr-1+cells become limiting