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At least 19 recordsLinked to original sources
PubMed1977

Modulation of lipopolysaccharide (LPS)-mediated function by structural differences of two physically distinct fractions of Escherichia coli K235 LPS.

Lipopolysaccharide (LPS), extracted from Escherichia coli K235 by the butanol water technique, was fractionated by gel filtration chromatography into high m.w. (LPS I) and low m.w. (LPS II) fractions. These two forms of LPS were characterized by different densities and chemical compositions. Chemical analysis provided evidence for greater amounts of lipid A and Lipd A-associated protein (LAP) per unit weight associated with LPS II. The biologic activity of the two LPS preparations was compared over a spectrum of different parameters. LPS II was shown to be a more potent mitogen and toxin than LPS I, whereas the two preparations were demonstrated to be of equal activity as polyclonal B cell activators, immunogens, and adjuvants. A modulatory role for the polysaccharide component of the LPS molecule is discussed.

Animals↗
PubMed1977

Activation of the classical and properdin pathways of complement by bacterial lipopolysaccharides (LPS).

Bacterial lipopolysaccharides (LPS) have been demonstrated to activate both the classical and the properdin pathways of complement. The lipid A region of the LPS is responsible for classical pathway activation and the polysaccharide region responsible for properdin pathway activation. Classical pathway activation by lipid A does not depend upon antibody to the lipid A and properdin pathway activation proceeds by a lipid A-independent mechanism. The polysaccharide portion of the LPS molecule exerts a modifying influence on the potential anticomplementary activity of the lipid A.

Complement System Proteins↗
PubMed1978

Membrane receptors of human erythrocytes for bacterial lipopolysaccharide (LPS).

The binding specificity of bacterial lipopolysaccharide (LPS) was investigated by inhibition experiments of the binding of 3H-labelled Escherichia coli lipopolysaccharide (LPS) AND 3H-labelled Salmonella minnesota R595 glycolipid and lipid A to human erythrocytes using various glycoproteins as inhibitors. PAS-1 glycoprotein and band-3 glycoprotein of human erythrocyte membranes exerted strong inhibitory activity. To characterize membrane receptors for LPS, solubilized membranes of human erythrocytes were subjected to affinity chromatography with an affinity adsorbent prepared by coupling S. minnesota R595 glycolipid to activated Sepharose 4B. Band-3 and PAS-1 glycoproteins were identified as major receptor sites.

Binding Sites↗
PubMed1978

Immunologic responsiveness of the C3H/HeJ mouse: differential ability of butanol-extracted lipopolysaccharide (LPS) to evoke LPS-mediated effects.

The lipopolysaccharide (LPS)-protein complex extracted from the cell wall of Escherichia coli K235 by the butanol-water technique has been shown to evoke a mitogenic response in bone marrow-derived (B) lymphocytes from the C3H/HeJ mouse strain. These mice are resistant to the effects of LPS extracted with phenol. Therefore, the ability of butanol-extracted LPS to modulate a spectrum of C3H/HeJ B-cell functions was investigated. Both butanol-extracted (LPS-B) and phenol-extracted (LPS-P) LPS preparations activated responder C3H/St spleen cell cultures to polyclonal antibody production, while only LPS-B activated C3H/HeJ spleen cells. Both LPS-P and LPS-B acted as adjuvants when injected after aggregated human gamma globulin (HGG) in C3H/St mice, but neither preparation was effective as a adjuvant in C3H/HeJ mice. LPS-P injected with deaggregated HGG (tolerogen) into LPS-sensitive mice has been shown previously to inhibit the induction of tolerance HGG. In the present studies, it was shown that LPS-B, but not LPs-p, was able to inhibit tolerance induction to HGG in the C3H/HeJ, whereas both preparations were effective in the C3H/St. LPS has also been shown to bypass tolerant T cells in LPS-sensitive mice late in tolerance to HGG at a time when B cells are responsive. However, in the C3H/HeJ, neither LPS-B nor LPS-P was capable of this function. The responsiveness of these B cells to HGG was demonstrated in transfer experiments. Thus, in the C3H/HeJ, LPS-B stimulates mitogenesis, polyclonal B-cell activation, and inhibition of tolerance induction, but cannot act as an effective adjuvant or as a bypass mechanism to activate B cells in the presence of tolerant T cells. The explanation for this pattern of responses may be attributable to yet another cellular defect in the C3H/HeJ mouse.

Adjuvants, Immunologic↗
PubMed1979

Synergy between T cell-replacing factor and bacterial lipopolysaccharides (LPS) in the primary antibody response in vitro: a model for lipopolysaccharide adjuvant action.

Unfractionated spleen cells, B cells from normal mice, and nu/nu spleen cells respond to the addition of bacterial lipopolysaccharide (LPS) and T-cell-replacing factor (TRF) by production of plaque-forming cells (PFC) in excess of the number expected from the addition of LPS and TRF separately. This synergistic activity is dependent on the presence of the antigen, SRBC. Supernatants of both allogeneic spleen cell mixtures and spleen cells cultured with Con A are effective and synergize best at concentrations suboptimal for their ability to act as TRF alone. Culture supernatants of unstimulated normal or fractionated cell populations are ineffective. Synergy is not dependent on the presence of macrophages in the cultures. Purified LPS free from active contaminants, as well as commercially available LPS, show synergy with TRF. Synergy was seen when TRF was added at initiation of culture or 24 hr later. It is suggested that synergy is the equivalent of LPS adjuvant activity, that the role of T cells in LPS adjuvanticity is that of a conventional cooperating cell, and the LPS acts as an adjuvant by inducing B cells to become more sensitive to T cell helper factors.

Adjuvants, Immunologic↗
PubMed1975

Immunologic properties of bacterial lipopolysaccharide (LPS): correlation between the mitogenic, adjuvant, and immunogenic activities.

Bacterial lipopolysaccharide (LPS) was demonstrated to have the capacity in mice to enhance the response to soluble bovine serum albumin (BSA) and to interfere with the induction of tolerance to human gamma-globulin (HGG). These adjuvant activities were shown to occur under conditions in which LPS could also function as a B cell mitogen. This positive correlation was established by utilizing two experimental situations in which LPS was non-mitogenic for spleen cells. Thus, on the one hand, it was found that LPS did not function as an adjuvant in C3H/HeJ mice, a unique strain whose spleen cells were also unresponsive to LPS-induced mitogenesis. On the other hand, in strains which did respond to LPS mitogenically, LPS failed to function as an adjuvant when it was chemically altered to reduce its in vitro mitogenic activity. A correlation was also observed between mitogenesis and the capacity of LPS to function as a specific immunogen i mice. In contrast to the sustained and prolonged plaque-forming cell response that was observed in mice whose spleen cells were also responsive to LPS-induced mitogenesis, the response was relatively transient in the C3H/HeJ strain. These results are discussed in view of the possible in vivo modes of action of LPS.

Adjuvants, Immunologic↗
PubMed1978

The effect of complement depletion on bacterial lipopolysaccharide (LPS)-induced hemodynamic and hematologic changes in the Rhesus monkey.

Lipopolysaccharide (LPS) isolated from Salmonella minnesota R595 or from Escherichia coli 0111:B4 induces hypotension in rhesus monkeys with normal complement levels. This hypotension is accompanied by decreased total peripheral resistance. The depletion of C3 and terminal complement components by prior intraperitoneal administration of the anticomplementary protein cobra factor did not alter the hemodynamic changes which occur following the rapid injection of 5 mg/kg of R595 LPS, the infusion of 500 microgram/kg of R595 LPS, or the injection of 500 microgram/kg of 0111:B4 LPS. We conclude that the LPS-induced hemodynamic changes in the subhuman primate are medicated by pathways which do not require the participation of C3. The kinetics and extent of the neutropenia and thrombocytopenia resulting from the injection of 0111:B4 or R595 LPS were not latered by prior depletion of greater than 95% of the plasma C3.

Animals↗
PubMed1976

The effects of age on the immune response to type III pneumococcal polysaccharide (SIII) and bacterial lipopolysaccharide (LPS) in BALB/c, SJL/J, and C3H mice.

Type III pneumococcal polysaccharide (SIII) and bacterial lipopolysaccharide (LPS) were used to evaluate B cell and T cell regulatory functions in BALB/c, SJL/J, and C3H mice of various ages. It was found that the BALB/c and C3H mice could mount high level plaque-forming cell (PFC) responses to SIII at various ages through 110 weeks whereas the levels of the SJL/J PFC responses had begun to decline by the age of 42 weeks through the age of 80 weeks. BALB/c mice were also capable of producing strong PFC responses to LPS at various ages through 110 weeks whereas the comparable SJL/J PFC responses to LPS had declined by 80 weeks of age. By using anti-lymphocyte serum (ALS) and low-dose paralysis to SIII, it was shown that suppressor T cell activity was apparently greater in young BALB/c mice than in older BALB/c mice. It was also found that paralysis to SIII in BALB/c mice was easier to achieve at an early age. SJL/J mice were found to have the necessary B cell activity to respond to SIII through 80 weeks of age and the PFC responses could be greatly enhanced by ALS. Implications of the roles of regulatory T cells in aging are discussed.

Aging↗
PubMed1978

Modulation of immune response by bacterial lipopolysaccharide (LPS): multifocal effects of LPS-induced suppression of the primary antibody response to a T-dependent antigen.

Spleen cells from mice injected with 2 to 50 microgram bacterial lipopolysaccharide (LPS) have a reduced capacity to make an antibody response in vitro to trinitrophenylated sheep erythrocytes (TNP-SRBC) when tested 1 to 7 days later. Recovery is gradual, and these cells are full functional 2 weeks after in vivo LPS treatment. Unresponsiveness resides in the nonadherent splenic cell populations, and can be shown to have a suppressive cell component, which is irradiation sensitive and has somme characteristics of a thymus-derived lymphocyte (T cell). In addition, neither bone marrow-derived lymphocytes (B cells) nor T cells in the spleens of LPS-treated mice are functionally normal in their abilities to cooperate during an antibody response in vitro. LPS-B cells cooperated poorly with nylon wool-enriched T cells from normal mice but cooperated well with irradiated carrier-primed T cells or nylon wool-purified splenic T cells from carrier-primed mice. LPS-T cells have a reduced capacity to interact with normal B cells and appear to contain a suppressor cell component. These results indicate that the effects of exposure of immunocompetent cells to LPS are multifocal and can include suppression as well as stimulation of antibody formation.

Animals↗
PubMed1977

Inhibition of the mitogenic response to lipopolysaccharide (LPS) in mouse spleen cells by polymyxin B.

The addition of low doses of the cationic polypeptide antibiotic, polymyxin B (PB), to cultures of mouse spleen cells inhibits lipopolysaccharide-(LPS) induced DNA synthesis but not that stimulated by PPD, PHA, or Con A. Inhibition is stoichiometric; the mitogenic response is suppressed by 50% at a weight ratio of PB:LPS of 0.055 to 1. Furthermore, PB-LPS complexes have a much reduced mitogenic capacity. These complexes inhibit the mitogenic response of spleen cells to unmodified LPS but not to PPD, Con A, or PHA. The inhibitory activity of PB is less effective when added after LPS is mixed with responding cells, achieving 50% inhibition when addition is made at 4 to 6 hr. Time course experiments indicate that partial inhibition is a reflection of a lower rate of DNA synthesis. Thus, PB inhibition of LPS mitogenesis apparently occurs as a result of formation of PB-LPS complexes with reduced mitogenic capacity. Specific inhibition by the complexes of mitogenesis induced by native LPS suggests that the inactive complex may bind to B cells but is unable to trigger them.

Animals↗
PubMed1976

Biological effects of Escherichia coli lipopolysaccharide (LPS) in vivo. I. Selection in the mouse thymus of killer and helper cells.

In the present study we have investigated the biological effects on thymus lymphocytes resulting from Escherichia coli lipopolysaccharide (LPS) treatment in young adult mice. It has been established that LPS induces the following effects: (a) a dose-dependent reduction of thymus weight contemporaneous with a rise in the anti-LPS antibody response; (b) an increase of killer activity of thymus cells; (c) an enhancement of thymocytes helper activity; (d) a reduction of theta-positive cells in the thymus; (e) a cellular depletion in the thymus cortex. These data, indicating that LPS selects in the thymus a population of cells more efficient in expressing both killer and helper functions, are interpreted as caused by an increased rate of cortisol secretion induced by the LPS treatment.

Animals↗
PubMed1977

Immunologic properties of bacterial lipopolysaccharide (LPS). IV. Cellular basis of the unresponsiveness of C3H/HeJ mouse spleen cells to LPS-induced mitogenesis.

Lymphoid cells obtained from the C3H/HeJ mouse strain respond abnormally to LPS in vitro, as shown by the fact that they are unable to make a mitogenic response to some LPS preparations and make only a low mitogenic response to other LPS preparations. In contrast, cells from a closely related C3H substrain, the C3H/St, are highly responsive to both types of LPS preparations. Experiments were carried out to determine the cellular basis of these genetically determined LPS response differences. This question was approached by studying the mitogenic response to LPS in cultures containing mixtures of various combinations of B cells, T cells, and macrophages from C3H/HeJ and C3H/St mice. Experiments utilizing an LPS preparation to which the C3H/HeJ is totally unresponsive (negative LPS) revealed, first, that either spleen cells, or partially purified T cells and/or macrophages obtained from C3H/St, could not restore the ability of C3H/HeJ spleen cells to respond to LPS, indicating that the C3H/HeJ is not deficient in an LPS-specific helper cell population which may be required for mitogenesis. Secondly, the addition of either spleen cells or partially purified T cells or macrophages from the C3H/HeJ to spleen cells from the C3H/St did not inhibit the mitogenic response to LPS, suggesting that the presence of suppressor cell activity is also not involved. Experiments analogous to those described, except utilizing another LPS preparation to which the C3H/HeJ is partially responsive (positive LPS), also failed to demonstrate reconstitutive or suppressive effects when C3H/HeJ and C3H/St spleen cells were admixed. The results obtained indicate that the defect in the C3H/HeJ mouse strain that limits its responsiveness to positive LPS and which renders it totally unresponsive to negative LPS appears to be an intrinsic defect in the capacity of B cells to react to the mitogenic stimulus of LPS.

Animals↗
PubMedDate not supplied

[In vitro stimulation of human T and B lymphocytes by lipopolysaccharide (LPS)].

The appearance of cells (CFC) having the property to cluster several layers of sheep red blood cells around themselves has been used in our laboratory as a marker for T cell activation. In this study, enumeration of stimulated T cells was carried out by this technique, whereas enumeration of B cells was carried out with surface Ig staining using fluorescein-labelled anti-Ig antibodies or F(ab)2 anti-Ig. Lymphocytes were stimulated in vitro for various lengths of time with the polyclonal mitogen PWM, the specific antigen Varidase and LPS added at culture initiation or 16 hours after beginning of culture. Our results confirm that human lymphocytes preincubated for 16 hours before addition of LPS give rise to higher numbers of CFC and blast cells, In all cases, less than half of these blasts reacted with the F(ab)2 anti-Ig, This suggests that under these conditions, LPS is not a mitogen specific for human B cells.

B-Lymphocytes↗