Comparison of the effect of two types of whole mushroom (Agaricus bisporus) powders on intestinal fermentation in rats.

The effects of two types of mushroom (Agaricus bisporus; white, WM; brown, BM) powders on intestinal fermentation in rats were investigated in terms of the physical characteristics of animals and by bacterial and HPLC analyses of cecal contents. Short-chain fatty acid levels were found to be significantly higher in the WM group than in the BM and the control (CN) groups; coliform bacteria levels in the BM group were significantly lower than those in the CN group, with the WM group inducing an apparent but insignificant decrease in coliforms. Anaerobe levels in the WM group were significantly higher than those in the CN group and, compared with the CN group, the BM and WM groups exhibited significantly increased feces weight and cecum weight, respectively. These results indicate that the mushroom powders, and in particular the WM powder, have beneficial effects on the intestinal environment in rats.

Intranasal Sendai viral vector vaccination is more immunogenic than intramuscular under pre-existing anti-vector antibodies.

Viral vectors are promising vaccine tools for eliciting potent cellular immune responses. Pre-existing anti-vector antibodies, however, can be an obstacle to their clinical use in humans. We previously developed a Sendai virus (SeV) vector vaccine and showed the potential of this vector for efficient CD8(+) T-cell induction in macaques. Here, we investigated the immunogenicity of SeV vector vaccination in the presence of anti-SeV antibodies. We compared antigen-specific CD8(+) T-cell responses after intranasal or intramuscular immunization with a lower dose (one-tenth of that in our previous studies) of SeV vector expressing simian immunodeficiency virus Gag antigen (SeV-Gag) between naive and pre-SeV-infected cynomolgus macaques. Intranasal SeV-Gag immunization efficiently elicited Gag-specific CD8(+) T-cell responses not only in naive but also in pre-SeV-infected animals. In contrast, intramuscular SeV-Gag immunization induced Gag-specific CD8(+) T-cell responses efficiently in naive but not in pre-SeV-infected animals. These results indicate that both intranasal and intramuscular SeV administrations are equivalently immunogenic in the absence of anti-SeV antibodies, whereas intranasal SeV vaccination is more immunogenic than intramuscular in the presence of anti-SeV antibodies. It is inferred from a recent report investigating the prevalence of anti-SeV antibodies in humans that SeV-specific neutralizing titers in more than 70% of people are no more than those at the SeV-Gag vaccination in pre-SeV-infected macaques in the present study. Taken together, this study implies the potential of intranasal SeV vector vaccination to induce CD8(+) T-cell responses even in humans, suggesting a rationale for proceeding to a vaccine clinical trial using this vector.