Enhancement of Natural Killer Cell Activity by Nocardia opaca Fractions

Abstract

Threir molecules derived Trom Nocardia nptica bacteria. NDCM, NWSMP. and PG. have been shown to express immunomodulating properties. The present study was aimed at assessing the effects of these derivatives on natural killer (NK) activity. Two experimental protocols were adopted, consisting of incubating whole or Percoll fractionated NK eells in vitro with those substances, and ihe other in which the dorivaiives were administered in vivo to mice and the aetivity assessed later. Incubalion of spleen cells in vitro with NWSMP or its precursor NDCM promoted NK activity. This effect could be observed after only 2 h ofincubation and continued until day 2. Percoll fractions I 3. which contain most of the NK activity, were enhanced to a similar extent. Band 4. which is usually devoid of such activity, remained unresponsive even after contact with the ,V. opaca derivatives. PG was practically IncfTcctivc upon all the subsets. The results of experiments in vivo correlated wilh those obtained in vitro in that NWSMP and NDCM, but not PG. promoted NK activity. Bands 1-3 were similarly enhanced, the effect was observed afler short treatment times, and could be partially cancelled by the concomitant administration of anti-interferon antibodies (anti-IFN Ab). All these Hndings suggest that the promotingefTeetsof/V. o/rucwderivatives are mediated through alpha beta IFN. In contrast to the results observed on spleen NK cells, NK cells from the peritoneum displayed susceptibility mainly to PG. and much less to NWSMP or NDCM. The administration of PG to mice in vivo had a particularly marked promoting efTect upon the cytotoxic aciivity of peritoneal cells. One logical explanation for the difTerence observed between PG and NWSMP or NDCM may be related to the specific IFN inducing properties of these compounds as well as to the different responsiveness of ihe NK cells present in the spleen and peritoneal cavity.

Nocardia species: host-parasite relationships

“…N-CWS-sensitized T lymphocytes stimulated with N-CWS were found to produce colony-stimulating factor (306). Several fractions derived from Nocardia opaca (Rhodococcus opaca) have been shown to have immunomodulating properties, including the enhancement of natural killer cell activity (45). The fractions were thought to stimulate the production of IFN-ot and IFN-1, which enhanced natural killer cell activity (45).…”

“…Several fractions derived from Nocardia opaca (Rhodococcus opaca) have been shown to have immunomodulating properties, including the enhancement of natural killer cell activity (45). The fractions were thought to stimulate the production of IFN-ot and IFN-1, which enhanced natural killer cell activity (45). It is not known whether N-CWS from N. asteroides cell wall fractions have effects similar to N-CWS of N. rubra or N. opaca (136); however, all of these organisms have similar basic cell wall components (199,200).…”

Nocardia fractions, NLD and NWSM, induce tumor necrosis factor‐α secretion in human monocytes: Role of protein kinase C

“…In contrast, NWSM was more potent than NDCM, a less purified fraction of Nocurdia, in reducing lung invasion in tumor-grafted mice [3]. NWSM had the most pronounced promoting effect on splenic NK activity, whereas peptidoglycan derivatives, the other molecule family extracted from Nocardia, induced a cytotoxic activity only in peritoneal cells [5].…”

“…They include adjuvanticity [2], in vivo anti-tumoral activity [3, 41, mitogenic activity for human B lymphocytes in a T cell-independent manner [l], and activation of NK cells [5]. In addition, the fractions of N .…”

Macrophage nitric oxide synthase (NOS) activation by Nocardia opaca fractions and 15- and 56-kD isolated antigens

“…Isolated fractions of Nocardia were shown to exert adjuvant effect [2], to induce regression of experimental tumours [3][4][5][6][7], to enhance protection against irradiation [8,9], and to promote resistance to infections [10]. These activities include activation of natural killer (NK) cells and macrophages, followed by enhanced cytotoxicity of these cells and production of tumour necrosis factor-alpha (TNF-), IL-1 and other cytokines [3,[11][12][13][14][15][16][17] and stimulation of B cells to proliferation and differentiation into immunoglobulin-secreting cells [1,2,10,18,19].…”