Prominent IL-12 Production and Tumor Reduction in Athymic Nude Mice after Toxoplasma gondii Lysate Antigen Treatment

Abstract

Toxoplasma gondii is an intracellular protozoan parasite that causes a Th1 cellular immunity. Our previous study showed that T. gondii lysate antigen (TLA) treatment in S180 tumor-bearing mice resulted in tumor reduction by suppressing CD31 expression, a marker of angiogenesis. In the present study, to investigate tumor suppressive effect of TLA under the absence of T lymphocytes, athymic nude mice were compared with euthymic mice in the anti-tumorigenic effect triggered by TLA in CT26 tumors. According to the results, intratumorally injected TLA reduced tumor growth and TIMP-1 level, a metastatic marker, in both euthymic and athymic mice. TLA treatment led to a sharp increase in IL-12 expression in serum cytokine profiling of athymic mice, and increased MyD88 signals in macrophages derived from the bone marrow, implying the activation of innate immunity. The selective induction of IL-12 by TLA treatment had an anti-tumorigenic effect.

Characteristics of Infection Immunity Regulated by Toxoplasma gondii to Maintain Chronic Infection in the Brain

“…According to the results of an earlier study, T. gondii infection is generally controlled by a strong Th1-type immune response via the cytokines IL-12p70, TNF-α, and IFN-γ. However, the recruited monocyte population is converted to an anti-inflammatory phenotype in order to restrain excessive immune responses during infection of T. gondii strain RH ( 3 – 6 , 12 , 14 , 21 , 22 ). On the other hand, the time of infection for the change in microglial cells and inflammatory responses as a cause of CI of the brain infected with strain ME49 it is not well defined.…”

The Neurotropic Parasite Toxoplasma gondii Induces Sustained Neuroinflammation with Microvascular Dysfunction in Infected Mice

“…The fact that tumor growth is suppressed in infected mice (or those treated with T. gondii lysates) is so far the only evidence that infection inhibits angiogenesis. 75,76 Decreased capillary perfusion, along with reduced angiogenesis in the brain, could generate focal hypoxia regions in the brain parenchyma, thus contributing to further degeneration. Chronic infection with T. gondii leads to decreased structural capillary density because IB4 staining at 40 and 180 dpi and immunostaining for laminin at 40 dpi showed reduced numbers of small vessels in brains of infected mice.…”

NaHCO3 enhances the antitumor activities of cytokine-induced killer cells against hepatocellular carcinoma HepG2 cells

“…Nude mice were selected due to their lack of cellular immunity (16). The results revealed that there was no difference between the NaHCO 3 feeding group and the control group in terms of luminescence intensities from the tumors.…”