In vitro immunological activities of an immunomodulating compound (biostim) extracted from klebsiella pneumoniae

Induction of interleukin 1 secretion by murine macrophages and human monocytes after stimulation by RU 41740, a bacterial immunomodulator

RU 41740, a glycoprotein extract from K. pneumoniae K2O1 strain, is an immunomodulating compound which has been shown to reduce infectious episodes in patients prone to recurrent infections. Data from preliminary experiments suggest that RU 41740 may affect several target cells, including T cells, B cells or macrophages. In the present report we show that RU 41740 can trigger mouse macrophages and human adherent mononuclear cells to produce interleukin 1 activity. Indeed, supernatants from mouse peritoneal adherent cells and human monocytes incubated in presence of RU 41740, can stimulate blastogenesis in thymocytes from C3H/HeJ mice. The data suggest that the immunomodulating effect of RU 41740 could be related to its ability to induce interleukin 1 production.

Immunological activities of RU-41740, a glycoproteic extract from Klebsiella pneumoniae. I.--Activation of murine B cells and induction of interleukin-1 production by macrophages

RU-41740, a glycoprotein extract from Klebsiella pneumoniae K2O1 strain, is an immunomodulating compound which has been shown to reduce infectious episodes in immunodeficient patients. Data from preliminary experimental designs suggested that RU-41740 could affect several target cells, such as T cells, B cells and macrophages. In the present report, we show that RU-41740 is a selective B-lymphocyte activator. It induces blast transformation in Nude mouse spleen cell cultures and in B-cell-enriched fractions obtained from normal mice. It does not activate T lymphocytes to proliferate. Activation of mouse B lymphocytes by RU-41740 is not affected by removal of adherent cells. RU-41740 also activates immunoglobulin secretion by murine B lymphocytes. Incubating spleen cells from C3H/HeJ mice with RU-41740 results in cell proliferation and activation of antibody-forming cells. This suggests that B-cell activation is not due to LPS contamination. Other experiments show that RU-41740 can also trigger mouse macrophages to produce interleukin-1 activity. Indeed, supernatants from peritoneal adherent cells incubated in the presence of RU-41740 can stimulate blastogenesis in thymocytes from C3H/HeJ mice. Thus, B-cell activation and IL-1 production by macrophages could constitute two additive mechanisms involved in immunomodulation induced by RU-41740.