The Rb1 fraction of ginseng elicits a balanced Th1 and Th2 immune response.

Porcine parvovirus (PPV) vaccines containing different adjuvants were evaluated for inducing Th1 or Th2 type of immunity in mice. Isotypes of antigen specific antibodies and levels of cytokines in serum and in lymphocyte culture supernatants measured by ELISA and the Gyrolab Bioaffy were used to determine the polarisation of the immune response. Enumeration of cytokine secreting cells was carried out by ELISPOT assays. Vaccines containing the ginseng-fraction Rb1 induced serum-detectable amounts of IL-4 and IL-10 as early as 24h after primary injection that was confirmed in sera collected at 24 and 72 h post re-vaccination. Five weeks after booster, immune lymphocytes were still producing large amounts of cytokines including IFN-gamma, IL-2, IL-4, IL-10 and TNF-alpha and the antibody titres were still similar to those titres recorded 1 week post booster. The Rb1 adjuvanted vaccines stimulated similar titres of antigen specific IgG1, IgG(2a) and IgG(2b). Thus, the cytokine and the serological data indicated that the Rb1 fraction of ginseng elicits a balanced Th1 and Th2 immune response.

A plant extract which enhances the plating efficiency of lymphoid cell lines and enhances the survival of normal lymphoid cells in vitro.

A water soluble extract from the bark of the Samoan medicinal plant Alphitonia zizyphoides A. Gray (Rhamnaceae), enhances the plating efficiency in vitro of lymphoid cell lines as well as the survival of bone marrow cells and normal T and B lymphocytes. Furthermore, the inclusion of bark-extract into culture media enhances the cloning efficiency of a T-hybridoma cell line by more than 30 times at otherwise unsuitably low serum concentrations, but does not completely substitute for serum. The enhanced growth of a B-cell hybridoma is also paralleled by an increased production of monoclonal antibodies in cultures containing low cell densities.