Resistance to facultative intracellular bacterial pathogens depends on acquired cell-mediated immunity and activation of macrophages by T- lymphocytes. Gamma interferon (IFN-gamma) is believed to be an important mediator of acquired cell-mediated immunity. In the present study, we evaluated the effect of Hochu-ekki-to (HET) on the survival rate and cytokine production with Salmonella infection model by using EL-4-bearing C57BL/6 mice. 1) When HET was administered orally to the tumor-bearing mice, it extended the survival time compared with non-treated controls in experimental infection by virulent strain 116-54. 2) The effect of HET on production of IFN-gamma in cultured splenocytes was tested by using the tumorbearing mice immunized with attenuated live SER strain. Spleen cells prepared from the mice treated with HET produced high levels of IFN-gamma compared with non-treated controls.
The results indicated that orally administered-HET enhanced protective ability to primary Salmonella infection and production of IFN-gamma accompanied by vaccination in EL-4-bearing C57BL/6 mice.

Risk factors for developing hemolytic uremic syndrome among patients with enterohemorrhagic Escherichia coli O157: H7 (EHEC) infection include age. The young, especially those under the age of five, face an increased risk, as do the elderly. In the present study, we evaluated the protective effects of Hochu-ekki-to (HET) on intraperitoneal infection with EHEC, using immunosuppressant, dexamethasone (Dex)-treated mice.
It was found that HET induced improvement of Dex-induced leukopenia. Similarly, the IgM-plaque forming cell responses to sheep red blood cell (SRBC) were restored by the administration of HET to the normal-mice level in Dex-treated mice. Consequently, HET was administered orally into the Dex-treated mice before infection with EHEC to observe the therapeutic effect. With the oral administration of 500mg/kg/head of HET into the Dex-treated mice, prolonged survival was shown: the 50% survival time in the HET-administered mice was four days, compared with one day in the non-administered controls. In addition, the number of bacteria in the liver was reduced by the administration of HET in the Dex-treated mice.
The results indicate that orally administered-HET protects against EHEC infection in Dex-treated mice, and such protective effects appear to be due to the restorative effects of HET against the Dex-induced immunosuppression.

A decline in the immunopotential of the host plays an essential role in the occurrence of infections with methicillin-resistant Staphylococcus aureus (MRSA) or other multi-drug resistant microorganisms. In the present study, mytomycin C (MMC)-treated mice with or without the infection of MRSA were used to examine the bacteriostatic action as well as the immunopotentiating action of the promising herbal medicine, Hochu-ekki-to (HET). Basic experimental data showed the drug to be effective in the treatment of MRSA infection. Eight to ten week old male C57BL mice were injected with MMC at a dosage of 5mg/kg/day to inhibit the bone marrow, thus creating a mouse model with reduced immunopotential. A powder extract of HET was administered orally at a dosage of 500mg/kg/day for seven consecutive days. For the infection of MRSA 1×10⁹ cell were injected intraperitoneally. Peritoneal macrophages were prepared by the adherence technique. Macrophage migration, phagocytic activity, and the bactericidal activity were examined by the Boyden chamber method, by the phagocytosis for fluorescent-activated latex beads, and by the nitroblue tetra zolium (NBT) reduction test, respectively.
After the administration of HET, the number of white blood cells in the MMC-treated mice recovered to 80% of the normal value. In addition, the phagocytic activity of macrophages increased to 50%, although that of the non-treated group was only 20%. The bactericidal activity also recovered to a level close to the normal value. The ratio of neutrophils in the HET administered MMC-treated group increased to 2.2% (normal mice, 2.6%) whereas that of the MMC-treated control group was 0.5%. Concerning the function of the immunological cells, IL-1beta and IFNgamma levels were recovered by treatment with HET, as observed by IL-1beta, IL-2 and IFNgamma monitoring. The bacterial count in the liver of the MRSA challenged mice, with or without HET administration peaked 6 hours after the challenge. The number of the group with HET administration was, however, much greater than that of the group without HET administration. The bacteria count in the blood showed an increase 12 and 24 hours after the challenge. Even 24 hours after the challenge, a significant number of bacterial cells existed in the blood of the group without HET administration, whereas only a small number of cells were detected 6 hours after the challenge. All of the control mice died 8 days after the MRSA challenge, whereas the survival rates were 60% for HET treatment, 40% for the vancomycin treatment, and 80% for the HET plus vancomycin treatment, respectively.
As we move towards a society with a high percentage of elderly people, the authors believe Chinese herbal medicine, which activates the immunopotential, will be very helpful in the treatment of opportunistic infections that are common among elderly patients.

In order to investigate an effects of the hot spring within a short period on immune system of human, the leukocyte, monocytes, lymphocyte and lymphocyte surface markers: CD2, CD4, CD8, CD16, CD19 and CD57 were tested in the human peripheral blood of twenty-three healthy volunteers by hot spring bathing. The results were as follows: Total number of leukocytes and lymphocytes in the peripheral blood significantly increased in an older group after hot spring bathing (p<0.01). However, we obtained a clear decrease in the number of granulocyte after hot spring bathing in the younger group (p<0.01). In addition, we found greater increase of the CD16⁺ cell counts and a clear decrease of the CD19⁺ cell counts in older group. But in younger group, we also obtained an increase of CD8⁺, CD16⁺ cells after hot spring bathing. These results indicated that hot spring bathing can regulate the physical immune system.
According to the percentage of lymphocytes or granulocytes in the total leukocytes, volunteers were divided into two types, more than 70% of granulocyte were recognized as G type and more than 40% of lymphocyte were divided in the L type. We found an increase of lymphocyte and lymphocyte subsets as well as a decrease in granulocyte in G group by hot spring bathing. But in L group, especially, indicated a greater increase in granulocyte and a decrease in lymphocyte subsets. We suggest that hot sping bathing can regulate by an autonomic nerve system, making it suitable.

We have simultaneously proved that cell populations taking charge of immunity in human peripheral blood can be regulated quantitatively by hot spring bathing. Now, we investigated the effect of hot spring bathing qualitatively on cytokine production by lymphocyte cell in human peripheral blood estimating by cytokine containing cell by FACScan. We found a significant increase in IFN-γ containing cells after hot spring bathing and an increase in IL-4 with no statistical significance after hot spring bathing. In addition, we found significant negative relationship between the level of IFN-γ, IL-4 and IL-1β before hot spring bathing and the ratio of cytokine that increased in variation after hot spring bathing. Namely, after hot spring bathing, there was a decrease of cytokine producing cells in subjects who had higher level before hot spring bathing. But an increase in subjects who had lower level before hot spring bathing, the trend was concentrated toward average levels in the cytokine production by lymphocyte in peripheral blood. So we suggest that hot spring bathing can promote acquired immunity to make it possible more suitable as immune reaction.