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High levels of soluble CD30 (sCD30) were detected in the serum and synovial fluid of patients with rheumatoid arthritis (RA), indicating the involvement of CD30+ T cells in the pathogenesis. We investigated the induction of CD30 and its functions in CD4+T cells from patients with established RA (disease duration >_2 years). CD4+ T cells from both the peripheral blood (PB) and synovial tissue (ST) of RA patients expressed surface CD30 when stimulated with anti-CD3 antibody (Ab) and anti-CD28 Ab, but their CD30 induction was slower and weaker compared with PB CD4+ T cells of healthy controls (HC). Immunohistochemical analysis showed that only a small proportion of lymphocytes expressed CD30 in the ST (-1%). RA PB CD4+ T cells, after recovery from 6-day stimulation with anti-CD3 Ab and anti-CD28 Ab, showed in intracellular cytokine staining that CD30+ T cells could produce more interleukin-4 (IL-4) but less interferon-gamma. In the culture of RA PB CD4+ T Cells with anti-CD3 Ab and anti-CD28 Ab, blocking anti-CD30 Ab similarly inhibited the cell proliferation and activation of nuclear factor-kappaB on day 4 in RA and HC, but inhibited the apoptotic cell death on day 6 only in RA. These results indicate that despite high-level expression of sCD30, the anti-inflammatory activity of IL-4-producing CD30+ CD4+ T cells may be limited in the ST due to a poor induction of surface CD30 and a susceptibility to CD30-mediated cell death.

Aeromonas are water-borne pathogens. They are halotolerant, which means that they can survive in environments whose salt content corresponds to that of seawater (3.0% NaCl). However, the presence of Aeromonas in seawater is extremely rare compared with that in river water. In this study, we tested the ability of Aeromonas sobria to produce toxins in river water and seawater. First, we cultured A. sobria on skim milk agar plates supplemented with either river water (SARW) or seawater (SASW). The bacteria grew on both plates. A clear zone around the bacteria was generated in SARW. However, such a zone was not observed in SASW, suggesting that proteases were not generated in SASW. Subsequently, we cultured A. sobria in a nutrient broth supplemented with either river water (NRW) or with seawater (NSW), and examined the protease activity of their culture supernatants. The protease activity of the culture supernatant from NSW was extremely low compared to that from NRW. The immunoblotting analysis showed that serine protease (ASP) was not produced by the culture in NSW. By contrast, aerolysin-like hemolysin was produced in all conditions examined in this study. This indicates that the salinity of water is deeply involved in the production of ASP by A. sobria.