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M Guenounou

Publications and source records attributed to M Guenounou.

At least 73 records · Page 4Linked to original sources
PubMed1984

[Activation of murine B lymphocytes by RU 41740, a glycoprotein extract from Klebsiella pneumoniae].

RU 41740, a glycoprotein extract from K. pneumoniae K2O1 strain, is an immune modulating compound which has been shown to reduce infectious episodes in deficient patients. Data from experimental designs suggest that RU 41740 could affect several target cells, such as T cells, B cells or macrophages. In the present report we show that RU 41740 is a selective B cell activator. It induces blast transformation in normal and nude mouse spleen cells and does not activate mouse T lymphocytes to proliferate. Activation of mouse spleen cells 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.

Animals↗
PubMed1983

Induction of interleukin 1 secretion by adjuvant-active peptidoglycans.

The ability of differently structured, purified peptidoglycans (PG) to induce interleukin 1 (IL1) secretion was compared. PG from Bacillus megaterium and Staphylococcus aureus stimulated the production of IL1 by mouse peritoneal macrophages and human adherent mononuclear cells, whereas PG from Micrococcus lysodeikticus and Corynebacterium poinsettiae were inactive. There was a correlation between the ability of PG to induce IL1 secretion and previously demonstrated immunoenhancing activities (adjuvant effect, increase of resistance to tumor growth) of PG. PG solubilization by lysozyme decreased but did not abolish the PG effect on IL1 secretion. Active PG induced IL1 production in nude mice and in the C3H/HeJ strain (which is unresponsive to lipopolysaccharides).

Adjuvants, Immunologic↗
PubMed1982

[Production of suppressor factor(s) in the in vitro antibody response by periodate oxidized spleen cells].

Sodium periodate treatment of Mouse spleen cells activated suppressor cells which act on the in vitro antibody response towards sheep erythrocytes or trinitrophenyl-polyacrylamide beads. Present study shows that suppression can be mediated by soluble factor (s) released in the cultures of periodate treated cells. Production of such suppressor factor (s) was associated to the presence of free aldehyde groups generated by periodate on the lymphocyte membrane. Control or cells successively treated by periodate and then reduced by borohydride were unable to produce suppressor factor (s). Suppressor factor (s) were stable at 56 degrees C (30 mn) and inactivated at 80 degrees C (10 mn).

Animals↗
PubMed1982

In vitro immunological activities of the polysaccharide fraction from Haemophilus influenzae type a endotoxin.

Mild hydrolysis of Haemophilus influenzae type a lipopolysaccharide by ion exchangers in the presence of chloroform, to remove the lipid moiety, yielded a nontoxic and immunogenic polysaccharide fraction. This polysaccharide selectively triggered murine B lymphocytes in vitro: (i) it induced enhancement of thymidine incorporation and stimulated antibody secretion in cultures of normal and nude mouse spleen cells; (ii) it did not stimulate splenic T lymphocytes; (iii) the activation of B lymphocytes was not absolutely dependent on the presence of macrophages. Sepharose 4B gel filtration showed that this polysaccharide consisted at least of two fractions: PS I (molecular weight [MW] 10(6)) and PS II (MW 10(4)). Only PS I was found to act as a polyclonal B cell activator. EDTA treatment dissociated the polysaccharide into PS III (MW 10(6)) and PS IV (MW 10(4)), which was not reassembled after the addition of 0.02 M CaCl2. Both fractions PS III and PS IV were unable to stimulate B lymphocytes. The immunological active fraction of H. influenzae polysaccharide is PS I. This fraction consists of a high-molecular-weight group (10(6)) and an association of 10(4)-MW aggregated units.

B-Lymphocytes↗
PubMed1981

Periodate-induced transformation of human peripheral blood lymphocytes and the resultant oxidation of membrane sialyl, galactosyl and fucosyl residues.

Oxidation of human peripheral mononuclear cells with sodium periodate results in lymphocyte activation. Period-date, at optimal mitogenic concentrations, oxidizes membrane sialyl residues (NeuNAc) essentially into the 7 carbon analogue (C7-NeuNAc). Fucosyl and galactosyl residues are also oxidized by periodate, since propane 1,2-diol and glycerol are isolated in acid hydrolysates of lymphocytes oxidized by periodate and reduced by tritiated borohydride. The neuraminidase pretreatment of lymphocytes induces a 40-50% decrease of their response to periodate. Neuraminidase treatment of 108 human peripheral lymphocytes liberated 9.6 microgram NeuNAc (31 nmol), representing 68.5% of the total content. The neuraminidase treatment dramatically enhances the recovery of glycerol in hydrolysates of lymphocytes treated successively with periodate and tritiated borohydride.

Fucose↗
PubMed1981

Characteristics of a lipid preparation (lipid A) from Haemophilus influenzae type a lipopolysaccharide.

Mild hydrolysis of Haemophilus influenzae type a lipopolysaccharide by ion exchangers yielded a lipid A extracted by chloroform. It contained phosphorus, glucosamine, and fatty acids. Myristic, palmitic, 3-hydroxymyristic, and oleic acids and two other unidentified long-chain fatty acids were found. The free lipid A was not toxic for mice at doses of up to 50 mg/kg and did not provoke a Shwartzman reaction. The Limulus test activity was positive up to 10(-12) g/ml, but the pyrogenicity in rabbits was lower than with the original lipopolysaccharide. However, the lipid A did induced a mitogenic response and polyclonal B-cell activation in mouse spleen cell cultures. Complexing lipid A with bovine serum albumin gave a nontoxic preparation which lost these immunological activities. Immunochemical studies showed that the major reactive determinants of this lipid-protein complex were altered after such a linkage. Consequently, the nontoxic and mitogenic lipid A isolated from H. influenzae type a did not exhibit all of the classical activities of lipid A preparations.

Animals↗
PubMed1980

[Effect of a mitogenic concentration on membrane glycoconjugates of human lymphocytes].

Periodate oxidation of human peripheral blood lymphocytes followed by reduction with 3H labelled sodium borohydride and acidic hydrolysis generates N-AN 7, glycerol and propane 1-2 diol. This indicates that sialyl, fucosyl and probably galactosyl residues are oxidized by periodate. Neuraminidase-treated lymphocytes exhibit decreased N-AN 7 levels, increased N-AN 8 levels and increased glycerol levels. Such results were neither found with mouse splenocytes nor with calf lymph node cells.

Cell Membrane↗
PubMed1980

Comparative study of biological activities and mitogenic effect of extracts from Haemophilus influenzae type a.

Two preparations designated as PWE and NCE were obtained from H, influenzae type a by treatment with either phenol water or hypertonic NaCl citrate respectively. The protein content of NCE was three fold higher than for PWE. Electroimmunodiffusion against H. influenzae antiserum disclosed an immunological relationship between NCE and PWE. The toxicity for mice was lower for both antigenic extracts (LD50 PWE: 47 +/- 7 mg/kg; LD50 NCE: 943 +/- 5 mg/kg) than for E. coli LPS. Limulus assay showed that both H. influenzae extracts had a weaker potency (100 to 1000 times less) than E. coli LPS. Sanarelli and Shwartzman reactions failed for PWE and NCE. The blast transformation of DBA/2 and nude mouse spleen cells were strikingly different for the three preparations: PWE, NCE, and E. coli LPS. Neither extract from H. influenzae cells showed the biological properties of a classical endotoxin. We suggest that they are endotoxin-like substances.

Animals↗
PubMed1979

Induction of suppressor cells by sodium periodate: the opposite expression of periodate-induced lymphocyte activation in spleen cells of normal and nude mice.

Normal mouse spleen cells treated with sodium periodate for 10 min at 4 degrees are stimulated to undergo blastogenesis and to incorporate thymidine. In contrast, periodate treatment does not stimulate DNA synthesis in nude mice spleen cells. The effect of such treatment on the antibody response in vitro induced by sheep red blood cells (SRBC) and by trinitrophenyl polyacrylamide (TNP-PAA), a T-independent antigen has been evaluated. Periodic-induced proliferation is accompanied by a marked inhibition of the immune response to both of these antigens in normal mouse spleen cells. Mild oxidation of nude cells with periodate markedly enhances their anti-TNP response elicited by TNP-PAA. The data suggest that periodate-induced immune suppression is associated with T lymphocytes. Furthermore, periodate-treated cells are capable of suppressing the in vitro antibody response of untreated normal cells.

Animals↗
PubMed1979

[Mechanism of lymphocyte activation by periodic acids. Blastogenesis and induction of immunomodulator populations].

Mild periodate treatment is mitogenic for T lymphocytes. With murine spleen cells periodate oxidation is effective between C8 and C9 on sialyl acid residues. With human blood lymphocytes this oxidation occurs between C7 and C8 of these residues. In vitro immune response is inhibited by periodate treatment. Activation of an immunosuppressive T lymphocyte population is obtained. Similar results are performed with human blood lymphocytes.

Animals↗
PubMed1978

[Effect of periodate oxidation of glycoconjugates of lymphocyte membranes on the immune response in vitro].

Mouse spleen cells treated with sodium periodate for 10 min. at 4 degrees C are stimulated to undergo blastogenesis and to incorporate thymidine. The effect of such treatment on the antibody response in vitro induced by Sheep red blood cells has been evaluated. Periodate-induced proliferation is accompanied by a marked inhibition of the immune response to this antigen. At concentrations leading to mitogenesis, no cytotoxic effect of periodate was observed and treated cells survived well on tissue culture. Cell recoveries from samples treated with periodate at the optimal mitogenic dose, were markedly enhanced when harvested at different days after culturing wheras lower antibody forming cells numbers wereconsistently observed during the culture period.

Animals↗
PubMed1978

Effect of magnesium deficiency and food restriction on the immune response in young mice.

Similar batches of five-week-old C57 Bl/6 mice were given either a magnesium-deficient diet (4mg Mg/100 g), or a control diet (40 mg/100 g). Control diet intake was either ad libitum or reduced. After immunization with SRBC (sheep red blood cells), the immune response was studied by estimating the number of spleen AFC (antibody-forming cells) capable of lysing SRBC, and by a cytoadhesion test to determine the number of RFC (rosette forming cells). Limitation of the control diet slowed the growth rate in mice. Whenever food intake was reduced from 4g/day to 2.9 or 2.6g/day, the AFC response intensified but the RFC response remained similar. Food limitation might therefore mainly affect immature IgM producing cells with a high dividing rate. Magnesium deficiency produced a drastic fall in the primary and secondary immune responses, as measured by the number of spleen AFC. The number RFC was also much lower in the spleen of deficient animals. Consequently, the spleen immune system is deeply affected by this deficiency.

Animals↗
PubMed1977

[Periodate oxidation of lymphocyte membrane glycoconjugates].

Mouse spleen cells free of erythrocytes were suspended in PBS at a concentration of 2 X 10(7) cells/ml and mixed with an equal volume of sodium periodate in PBS for 10 min. at 4 degrees C to give a final concentration of periodate ranging from 10(-4) M to 5 X 10(-3) M. The cells were then washed and suspended (60 X 10(6) ml) in PBS containing 3H-labelled sodium borohydrate and incubated for 30 min, at 23 degrees C. Following this, the cells were washed and the pellets treated with H2SO4 0.1 N for 60 min. at 80 degrees C. Compounds liberated by such treatment, were identified by chromatography as derivates of sialic acid. The data provide direct evidence that the mitogenic effect of sodium periodate is associated to the oxidation of the sialic acid residues on the lymphocyte membrane.

Animals↗
PubMedDate not supplied

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.

Animals↗
PubMedDate not supplied

RU-41740 (K. pneumoniae glycoprotein) enhances resistance to experimental candidiasis and stimulates phagocytic functions.

RU-41740, a purified glycoprotein extract from Klebsiella pneumoniae, (which is an efficient non-specific immune activator in a broad spectrum of in vitro and in vivo reactions) was administered either orally or parenterally in the mouse. It enhanced the resistance of mice to candidiasis, both in terms of survival rate and a decrease in viable yeast cell recovery in kidneys. The drug administered at 0.1 mg or 1 mg/kg augmented 4-fold the mean survival time (MST) of animals infected with 1 to 2 X 10(6) Candida albicans, both by the intraperitoneal and the intravenous route. The effect of the orally administered drug was less striking but nonetheless present. At 10 mg/kg, the MST of infected animals increased about 2-fold. In vitro, in the presence or absence of zymosan, the drug at 10 or 100 micrograms/ml was able to stimulate the phagocytic process of elicited mouse peritoneal cells (65% polymorphonuclear cells, 35% macrophages) and human peripheral blood cells (95% polymorphonuclear cells, 5% monocytes) in terms of activated oxygen species production. The involvement of polymorphonuclear cells in the mechanisms of natural resistance to C. albicans infection led us to discuss the role of these cells as targets for the drug.

Animals↗