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D C Morrison

Publications and source records attributed to D C Morrison.

At least 181 records · Page 10Linked to original sources
PubMed1977

Chemical and biological properties of a protein-rich fraction of bacterial lipopolysaccharides. II. The in vitro rat peritoneal mast cell response.

Lipid A-associated protein (LAP) isolated from preparations of bacterial lipopolysaccharides (LPS, endotoxins) has been demonstrated to initiate the release of amines from rat peritoneal mast cells. The release at low concentrations of LAP requires both cellular energy and calcium, and thus appears to be a true secretory response. At higher concentrations the release is independent of these variables. The time required for maximal response is approximately 10 to 15 min at 37 degrees C. The response appears to be a general property of Escherichia coli LAP preparations since LAP isolated from three serotypes of these organisms all have similar activity. On the basis of heat lability at 100 degrees C, the ability of LAP to initiate mast cell secretion appears to be independent of its ability mitogenically to stimulate murine B lymphocytes.

Animals↗
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↗
PubMed1976

Isolation of a lipid A bound polypeptide responsible for "LPS-initiated" mitogenesis of C3H/HeJ spleen cells.

The experiments by Sultzer and Nilsson (1), and later by Watson and Riblet (2), established that spleen cells from the C3H/HeJ strain of mouse were refractory to the mitogenic effects of bacterial lipopolysaccharides (LPS). More recently, however, experiments from our laboratory (3) demonstrated that spleen cells from C3H/HeJ mice were in fact responsive to some preparations of LPS but not to others, and that the method of extraction played a critical role in determining activity. In particular, preparations of LPS prepared by extraction with aqueous butanol had potent mitogenic activity. Our data showed that the mitogenic activity of such positive preparations of LPS coisolated with the LPS during gel filtration chromatography and subsequent equilibrium banding on CsCl. In addition, lipid A isolated from positive preparations of LPS was also capable of stimulating C3H/HeJ spleen cells. Taken together, these experiments provided rather convincing data that it was the LPS (in particular the lipid A) itself, or some contaminant very tightly bound to the lipid A, which was responsible for its biological activity. We further demonstrated that treatment of positive preparations of LPS with hot phenol rendered such preparations nonmitogenic for C3H/HeJ spleens, yet activity for other strains was only moderately decreased. These experiments would suggest either that the phenol treatment chemically alters the lipid A region of the LPS molecule or that such treatment removes the putative tightly bound contaminant responsible for C3H/HeJ mitogenesis. In the experiments reported here, we have explored in greater detail the role of lipid A in the stimulation of C3H/HeJ spleen cells. For these experiments we have utilized our earlier observations that the antibiotic polymyxin B forms a highly stable molecular complex with the lipid A region of LPS (4), and that such polymyxin B-LPS complexes are unable to mitogenically stimulate B lymphocytes (5). In addition, we have attempted to distinguish between the two potential modes of action of phenol on LPS, namely, the chemical alteration of the lipid A or the removal of a tightly bound contaminant by phenol treatment. The results of the experiments we report here support the interpretation that mitogenic activity of positive preparations of LPS is associated with a low mol wt phenol soluble polypeptide of approximately 10,000 mol wt. After partial purification, this polypeptide intitiates a significant mitogenic response at concentrations as low as 10 mug/ml. We conclude that the C3H/HeJ strain of mouse is a true nonresponder to the stimulatory effects of the lipid A region of LPS.

Animals↗
PubMed1976

Dissociation of anticomplementary and adjuvant properties of proteins derived from cobra venom.

The ability of preparations of cobra factor (CoF) to convert C3 via the properdin pathway (anticomplementary activity) has been demonstrated to be unrelated to its ascribed ability to convert a tolerogenic signal into an immunogenic stimulus (adjuvant activity). It has been shown that CoF preparations which have become inactive with regard to anticomplementary activity still retain full adjuvant properties. Further, when both activities are present in preparations of CoF, they can be separated by gel filtration chromatography into a fraction with approximate molecular weight 150,000 which contains anticomplementary activity and a fraction with approximate molecular weight 20,000, which contains adjuvant properties.

Adjuvants, Immunologic↗
PubMed1975

Immunologic properties of bacterial lipopolysaccharide (LPS). II. The unresponsiveness of C3H/HeJ Mouse spleen cells to LPS-induced mitogenesis is dependent on the method used to extract LPS.

The C3H/HeJ mouse strain, previously shown to be a nonresponder to bacterial lipopolysaccharide (LPS)-induced mitogenesis in vitro, was demonstrated by the present studies to be competent to respond mitogenically to LPS, but only to LPS preparations obtained by selected extraction methods. These preparations appear to be confined to LPS isolated by mild extraction techniques, such as TCA or butanol. In contrast, those obtained by techniques utilizing phenol were only weakly stimulatory or completely nonstimulatory for spleen cells from the C3H/HeJ. All LPS preparations tested, on the other hand, were highly stimulatory for cells from another mouse strain, namely the C3H/St. The critical importance of the method of extraction of LPS on its mitogenic activity for C3H/HeJ cells was stressed by experiments in which LPS was prepared from Escherichia coli K235 using either of two procedures. In these experiments, phenol-extracted LPS, although mitogenic in the C3H/St, was completely nonstimulatory in the C3H/HeJ; whereas, butanol-extracted LPS was highly stimulatory in both strains of mice. This striking difference was attributed to a destructive effect of phenol on LPS, as demonstrated by the fact that treatment of butanol LPS with phenol resulted in a total loss of its mitogenic activity in the C3H/HeJ, but in only a partial loss in the C3H/St. In general, the mitogenic response observed with selected LPS preparations in the C3H/HeJ was quantitatively lower and more transient than that seen with the C3H/St, although qualitatively these responses appeared to be similar. This was evidenced by the observation that in both mouse strains LPS was a specific mitogen for B cells, a property which was also attributed in both strains to the same distinct structural region of the LPS molecule, that is lipid A. A preparation of LPS that failed to stimulate B cells from the C3H/HeJ nonetheless had the capacity to block activation of these B cells by a stimulatory preparation of LPS. These results strongly suggest that mitogenic stimulation of B cells by LPS is a function of the structural integrity of both the LPS molecule and putative B-cell receptors for LPS.

Animals↗
PubMed1975

Mediation systems in bacterial lipopolysaccharide-induced hypotension and disseminated intravascular coagulation. I. The role of complement.

We have studied the role of complement in lipopolysaccharide (LPS)-induced hypotension and disseminated intravascular coagulation (DIC) by comparing the effects of injection of three preparations of LPS from E. Coli 0111:B4, S. minnesota Re595, and S. marcescens. Injections of nonlethal doses of these LPS preparations into normal rabbits produced decreases in mean arterial blood pressure during a 5-h period. When rabbits treated with cobra venom factor (CoF) to deplete C3 were injected with the various LPS preparations, mean arterial pressures fell at a rate and extent essentially identical to that observed in normal rabbits. Rabbits genetically deficient in C6 also demonstrated LPS-induced hypotensive changes. Only minimal, or no changes in plasma C3 levels or serum CH50 values were detected in normal rabbits after LPS injection. Hypotensive changes were also induced in rabbits when complement was rapidly activated by intravenous injection of CoF. In contrast to the hypotension induced by LPS, the fall in arterial pressure associated with the consumption of complement was short lived and required the rapid consumption of considerable amounts of C3. The occurrence of DIC noted in normal rabbits injected with each preparation of LPS was not inhibited in either rabbits treated with cobra factor or in C6-deficient rabbits. The DIC was most pronounced after injection of Re595 and S. marcescens LPS. Injection of the various LPS preparations produced a rapid disappearance of circulating neutrophils and mononuclear cells, which occurred with the same kinetics and to the same extent in normal, CoF-treated, and C6-deficient rabbits. Injection of either Re595 LPS or S. marcescens LPS produced a biphasic disappearance of circulating 51Cr-platelets. In contrast, injection of 0111:B4 LPS affected only slightly the rate of disappearance of 51Cr-platelets. Depletion of C3 by cobra factor treatment had no effect on the disappearance of platelets in animals injected with 0111:B4. In marked contrast cobra factor treatment greatly reduced the initial rapid disappearance of platelets in rabbits injected with either Re595 or S. marcescens LPS, but had no effect in the secondary disappearance phase.

Animals↗
PubMed1975

Dissociation between mitogenicity and immunogenicity of TNP-lipopolysaccharide, a T-independent antigen.

Two models have been proposed to explain triggering of B cells by so-called "T-independent antigen." Feldmann and Basten (1) proposed that the interaction of multiple repeating determinants on polymeric antigens with specific Ig receptors on the B-cell surface is sufficient to provide the signals for division of these cells and differentiation to antibody-forming cells. In contrast, coutinho et al. (2, and see review, 3) have claimed that there is only one signal, a mitogenic signal, receptors acting merely as passive focusing devices to localize the antigen on specific cells where it delivers a mitogenic signal resulting in differentiation to an antibody-producing cell. This model rests primarily on the demonstration that at high concentration all T-independent antigens they have tested are mitogenic for B cells (4-6). Compatible with this hypothesis are the observations that hydrolysis of lipopolysaccharide (LPS) to remove the ester- linked fatty acids of the mitogenic lipid A component abrogates its mitogenic (7,8) activity as well as its ability, when substituted with the TNP hapten, to induce a T-independent anti- TNP response (9). However, alkali treatment of LPS, although not changing its antigenic component (8), may also modify the molecule physically or chemically which could account for loss of immunogenic properties (10). We therefore investigated other reagents which interact with LPS in a more chemically defined manner in an effort to clarify the relationship between the mitogenic and immunogenic properties of this molecule. Polymyxin B (PB) is one of a family of cyclic peptide antibiotics which are bactericidal for most gram-negative bacteria. It prevents the lethal endotoxic activity of LPS (11, 12) and changes the physical structure of LPS (13). We report here that low doses of PB added to cultures of mouse spleen cells inhibit the mitogenic activity of TNP-LPS, a T- independent antigen, and native LPS, but do not suppress the immune response to TNP-LPS. PB interacts with TNP-LPS and LPS causing a physical change in the molecule. In addition, polymyxin-treated LPS is no longer mitogenic. These results suggest a dissociation between the mitogenic and immunogenic properties of TNP-LPS.

Animals↗
PubMed1975

Fractions of lipopolysaccharide from Escherichia coli O111:B4 prepared by two extraction procedures.

Lipopolysaccharides have been extracted from Escherichia coli O111:B4 by phenol extraction and by a new method employing aqueous butanol. Both methods yield very similar lipopolysaccharide preparations. Gel filtration chromatography of either preparation yields two physically and chemically distinct lipopolysaccharide fractions. One fraction contains lipopolysaccharide molecules with long antigenic side chains. It acts like a highly asymmetric unit with an apparent weight of 1.5 times 10-6 and is not dissociated by detergents or deacylation. The second fraction has a short antigenic side chain and can be dissociated by sodium dodecyl sulfate and Triton X-100 into units of approximately 90,000. Some properties of the lipopolysaccharide fractions vary with the method of extraction.

Butanols↗
PubMed1975

Stimulation of a T-independent primary anti-hapten response in vitro by TNP-lipopolysaccharide (TNP-LPS).

The trinitrophenyl hapten (TNP) has been covalently conjugated to bacterial lipopolysaccharides (LPS) to give TNP-LPS. The site of attachment has been suggested to be in the core polysaccharide and lipid A region of the molecule and approximately 2.4 hapten molecules are bound per monomer LPS molecule. The TNP-LPS has been demonstrated to be immunogenic in vitro at very low concentration. This antigen has further been shown to initiate a T-independent TNP-PFC response. The immunogenicity of TNP-LPS is abrogated by mild alkaline hydrolysis, suggesting a requirement for intact lipid A in the initiation of an immune respose at the very low concentrations of antigen used.

Alkalies↗
PubMed1975

The initiation of mast cell degranulation: activation at the cell membrane.

The low molecular weight mast cell activator, polymyxin B, has been covalently bound to an insoluble matrix of Sepharose 4B. It has been demonstrated that mast cells in preparations of rat peritoneal cells bind to Sepharose 4B-polymyxin B beads but not to control beads. The bound cells are stimulated to degranulate by this interaction at the cell membrane with the resultant release of biogenic amines.

Animals↗
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↗
PubMed1974

Direct evidence for Hageman factor (factor XII) activation by bacterial lipopolysaccharides (endotoxins).

Purified precursor Hageman factor has been demonstrated to bind to soluble bacterial lipopolysaccharide (LPS, endotoxin) isolated from Escherichia coli 0111:B4, and this complex has been shown to have the capacity to convert prekallikrein to its active form. In addition, LPS-activated Hageman factor substantially reduces clotting times in XII-deficient plasma. The capacity to activate Hageman factor has been demonstrated to reside in the lipid A region of the LPS molecule. Activation of Hageman factor by LPS contrasts with fluid-phase activation (e.g., by kallikrein or trypsin) in that no cleavage to lower molecular weight fragments occurs. High concentrations of LPS inhibit the activity of Hageman factor, probably by a direct LPS-Hageman factor interaction.

Animals↗