Molecular requirements for B-lymphocyte activation by Escherichia coli lipopolysaccharide

Certain Escherichia coli mutants altered in phosphatidylglycerol metabolism accumulate fatty acyl derivatives of glucosamine 1-phosphate. Especially prominent is 2,3-diacylglucosamine 1-phosphate (previously designated lipid X), which may be an early precursor of lipid A. We have examined the activity of lipid X (Mr = 711.9) and several related compounds as mitogens towards mouse lymphocytes. As judged by labeling with [methyl-3H]thymidine, lipid X is mitogenic, and it mimics the properties of lipopolysaccharide and lipid A. The following evidence suggests that lipid X exerts its effects by a route similar to that of lipopolysaccharide: (i) lymphocytes from C3H/HeJ mice, which are unresponsive to lipopolysaccharide, are also not stimulated by lipid X; (ii) polymyxin B abrogates lymphocyte stimulation by lipid X; and (iii) lipid X induces the proliferation and maturation of lymphocytes to antibody-producing plaque-forming cells. Selective removal of the ester-linked hydroxymyristate moiety at position 3 totally abolishes mitogenic activity. Other phospholipids, such as phosphatidic acid, CDP-diglyceride, phosphatidylcholine, and lysophosphatidylcholine, have no activity as mitogens. If lipid X and lipid A induce by common mechanism(s) B-lymphocyte proliferation, then it follows from structural comparison that the reducing-end subunit of lipid A is the minimal structural requirement for this activity. Because the structure of lipid X is completely defined, biochemical and pharmacological dissection of B-cell activation by lipopolysaccharide should now be possible.

[Variations in the level of immunosuppressive acidic protein in patients with gynecologic tumors and pregnant women]

Immunosuppressive acidic protein (IAP) was determined in sera of patients with gynecologic tumors and pregnant women using the single radial immunodiffusion method. The normal limit of IAP of 490 micrograms/ml was derived from the mean value +2S.D. of IAP in 150 healthy females. Among 141 patients with gynecologic cancers, serum IAP was elevated in 87 patients (62%). Among 190 patients with benign tumors (98 uterine myoma, 92 benign ovarian tumors) serum IAP was elevated in 14 patients (7%). The level of IAP in sera of 201 pregnant women was almost identical with that of the healthy females. Elevated levels of IAP were recognized in 43% of 77 patients with cervical cancer, in 55% of 11 endometrial cancer patients and in 91% of 53 ovarian cancer patients. IAP determination was most effective in ovarian cancer for the early detection of cancer. IAP determinations may provide a useful method for the detection of recurrence of cervical cancer.

Fatty acyl derivatives of glucosamine 1-phosphate in Escherichia coli and their relation to lipid A. Complete structure of A diacyl GlcN-1-P found in a phosphatidylglycerol-deficient mutant

We have determined the complete structure of a glycolipid (designated lipid X) previously found to accumulate in certain Escherichia coli mutants defective in phosphatidylglycerol synthesis (Nishijima, M., and Raetz, C.R.H. (1979) J. Biol. Chem. 254, 7837-7844). Based on fast atom bombardment mass spectrometry and proton nuclear magnetic resonance studies, this substance is an acylated metabolite of glucosamine 1-phosphate. Lipid X of E. coli has a Mr = 711.87 as the free acid (C34H66NO12P) and contains two beta-hydroxymyristate moieties, one attached as an amide at the 2 position and the other as an ester at the 3 position of the sugar. It has free hydroxyl groups at the 4 and 6 positions, and the anomeric configuration is alpha. The structure of lipid X from E. coli closely resembles the reducing end subunit of lipid A, and it might represent a very early precursor in the biosynthesis of lipid A. To our knowledge, fatty acyl derivatives of glucosamine 1-phosphate have not been reported previously.

[Immunosuppressive acidic protein in patients with gynecologic cancer]

Immunosuppressive acidic protein(IAP) levels were measured in human sera by a single radial immunodiffusion using an IAP plate. Sera were obtained from healthy controls (79 females), patients with myoma uteri (53 cases), patients with benign ovarian tumors (44 cases) and patients with cervical (33 cases), endometrial (6 cases) and ovarian (33 cases) cancer. The mean IAP values for patients with myoma uteri (375 +/- 72 micrograms/ml), benign ovarian tumors (375 +/- 92 micrograms/ml), cervical cancer (506 +/- 236 micrograms/ml), endometrial cancer (563 +/- 159 micrograms/ml), and ovarian cancer (1051 +/- 466 micrograms/ml) were statistically significantly higher than that of controls (298 +/- 92 micrograms/ml). Elevated levels of IAP were found in sera of 11% patients with myoma uteri, 7% with benign ovarian tumors, 34% with cervical cancer, 83% with endometrial cancer and 94% with ovarian cancer. Elevation of IAP was recognized in 83% patients with endometrial cancer and in 100% of patients with ovarian cancer in stage I, while only 10% of patients with cervical cancer in stage I showed elevated IAP. No clear relationship between the IAP level and the stage of the disease in the patient or with the histological type was found. Serial IAP determination appeared to provide a useful marker in cancer patients. The measurement of serum IAP is recommended as an addition to the conventional diagnostic system.

[Pregnancy-associated alpha 2-glycoprotein in patients with gynecologic cancer]

Pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG) levels were measured in human sera by a modification of Laurell's electroimmunoassay using rabbit anti-alpha 2-PAG serum. Sera were obtained from healthy controls (68 females), patients with myoma uteri (25 cases), patients with benign ovarian tumors (23 cases) and patients with cervical (19 cases), endometrial (4 cases) or ovarian (23 cases) cancers. The mean values of alpha 2-PAG in patients with myoma uteri (7.3 +/- 2.3U/microliters), benign ovarian tumors (5.0 +/- 3.1U/microliters), cervical cancer (8.8 +/- 4.4U/microliters), endometrial cancer (17.5 +/- 7.6U/microliters) and ovarian cancer (12.0 +/- 4.0U/microliters) were statistically significantly higher than that of controls (2.0 +/- 2.8U/microliters). Elevated levels of alpha 2-PAG were found in sera of 44% patients with myoma uteri, 17% of benign ovarian tumors, 63% of cervical cancer, 100% of endometrial cancer and 83% of ovarian cancer. Elevation of alpha 2-PAG was recognized in 100% patients with endometrial cancer and in 67% patients with ovarian cancer in stage I, while no patient with cervical cancer in stage I showed elevated alpha 2-PAG. No clear relationship of the alpha 2-PAG levels with the stages of the patients nor with the histological types of tumor was found. Serial alpha 2-PAG determination appeared to provide a useful marker in cancer patients. The measurement of serum alpha 2-PAG is recommended as an addition to the conventional diagnostic system.

Projections of upper structure to the spinal cardioacceleratory center in cats: an HRP study using a new microinjection method

We studied, with the horseradish peroxidase (HRP) method, the supraspinal structure projections to the cardioacceleratory center in the intermediolateral nucleus (ILN) of T3-4 segments of the cat spinal cord. A fiber-filled double-barrel coaxial electrode was devised. The inner barrel electrode, filled with 3 M NaCl solution, was used for stimulating intraspinal structures to determine the cardioacceleratory center. The outer barrel electrode with an Agar stop, filled with a 20% HRP solution, was used for injecting HRP by pulses of positive electric current. In every experiment, HRP was injected into 3 points within the cardioacceleratory center at intervals of 1 mm. Out of 36 experiments, 10 showed that the HRP injection sites were centered in and almost confined to the ILN, and the population of the HRP-labeled cells was not less than 50. Some 1146 HRP-labeled cells were thus identified. They were distributed in the medulla oblongata (72.1%), pons (10.2%), midbrain (8.5%) and hypothalamus (9.2%). They were concentrated in the medullary reticular formation (37.8%), median raphe (26.9%) and pontine reticular formation (10.2%). Contrary to expectation, the HRP-labeled cells were few in the nucleus tractus solitarii (3.7%), paraventricular hypothalamic area (3.3%) and nucleus locus coeruleus (none).

Purification and structural determination of nontoxic lipid A obtained from the lipopolysaccharide of Salmonella typhimurium

Endotoxin extracted from the heptose-less mutant of Salmonella typhimurium was hydrolyzed in 0.1 N HCl in methanol/water (1:1, v/v) at 100 degrees C to yield lipid A, which was then fractionated on a Sephadex LH-20 column to yield a major monophosphoryl lipid A fraction. The monophosphoryl lipid A was further fractionated by preparative thin layer chromatography. This process yielded three major bands (TLC-1, -3, and -5) and two minor bands (TLC-7 and -9). The purity of these fractions was established by ion exchange and reverse phase high performance liquid chromatography. The thin layer fractions were analyzed by fast atom bombardment mass spectrometry. TLC-1 and -3 gave molecular ions (M-H)- at m/e 1730 and 1716, respectively. Both of these fractions contained beta-hydroxymyristic, lauric, and 3-myristoxymyristic acids in O-acyl linkages. The molecular formula and Mr of TLC-1 are C95H179O22N2P and 1731.16; those of TLC-3 are C94H177O22N2P and 1717.15. TLC-1 was a methyl homolog of TLC-3. The major component of TLC-5 (C80H151O22N2P and Mr = 1506.99) gave a molecular ion at m/e 1506 and contained two beta-hydroxymyristic acids and a lauric acid in the O-acyl linkages. The major component of TLC-7 (C66H125O19N2P and Mr = 1280.83) and the single component of TLC-9 gave molecular ions at m/e 1280 and 1098, respectively. TLC-7 contained lauric and beta-hydroxymyristic acids in the O-acyl linkages. TLC-9 (C54H103O18N2P and Mr = 1098.69) contained a single O-acylated beta-hydroxymyristate group. TLC-1 and -3 were nontoxic in the chick embryo lethality test and regressed established tumors in the syngeneic guinea pigs.

Sites of origin and termination of gastric vagus preganglionic neurons: an HRP study in the rat

Using the horseradish peroxidase (HRP) method, we studied the relation between sites and forms of gastric vagus preganglionic neurons in the rat and gastric regions on which they project. Fifty microliters of a physiological saline solution containing 3 mg of HRP was injected into 6 different gastric regions: cardia, lesser curvature, pyloric antrum, greatger curvature, ventral corpus and dorsal corpus. After a survival period of 24h, the medulla oblongata was serially sectioned and processed for histochemical demonstration of HRP. In the medulla oblongata, HRP-labeled cells were distributed in 2 regions: (1) in the regions within the dorsal vagus nucleus (DVN); (2) in the regions within the ambiguous complex. The labeled cells in the DVN were observed in every experiment, while ones in the ambiguous complex were only seen in the cardia and lesser curvature experiments. In the ventral corpus experiment the labeled cells were observed dominantly on the left side and in the dorsal corpus experiment dominantly on the right side. The majority of the labeled cells in the ambiguous complex were medium-sized and multipolar in shape, while the majority of ones in the DVN were medium-sized and fusiform in shape.

Effects of ethambutol on accumulation and secretion of trehalose mycolates and free mycolic acid in Mycobacterium smegmatis

We examined the early effects of ethambutol on the synthesis of trehalose monomycolate, trehalose dimycolate, and free mycolic acid in actively growing cells of Mycobacterium smegmatis. At about 1 min after the addition of 3.0 micrograms of ethambutol per ml, the cellular level of trehalose monomycolate began to increase over the control culture. This was followed 8 to 12 min later by the cellular increases in free mycolic acid and trehalose dimycolate over the control culture and the inhibition of incorporation of mycolic acid into the cell wall. Exposure of M. smegmatis to ethambutol for more than 30 min caused all of these lipids to leak out of the cells more rapidly than in the control cells. The mechanism by which ethambutol initiates these events is unknown, but these early imbalances in lipid synthesis may be responsible for the lethal action of this drug.

Mechanism of natural resistance to vincristine in rat ascites hepatoma AH66

It was found that AH66, a rat ascites hepatoma inherently refractory to vincristine, exhibited definite resistance to a different class of antitumor agents- adriamycin and actinomycin D. In comparative studies with AH13, a sensitive strain of rat hepatoma, significantly lower levels of cellular retention as well as uptake of these drugs were observed with AH66 cells. However, in the presence of 2, 4-dinitrophenol in glucose-free medium, the uptake of vincristine by AH66 cells was remarkably increased, and addition of glucose induced a spontaneous efflux of drug that had been taken up. These results, in good accord with those for a subline of P388 mouse leukemia which acquired resistance to either adriamycin or vincristine, suggest that there exists an active efflux system common to these different kinds of antitumor agents in naturally resistant rat tumor cells. Further studies revealed that Tween 80 also enhanced the uptake of vincristine by AH66 cells by interfering with the efflux of this drug and thus partially restored the sensitivity in vitro of AH66 cells to vincristine.

Isolation of a nontoxic lipid A fraction containing tumor regression activity

Galanos-type endotoxin obtained from the heptose-less mutant of Salmonella typhimurium was converted to Lipid A by two cycles of treatment with sodium acetate, pH 4.5, at 100 degrees and separated on a DEAE-cellulose column into several fractions (Fractions III to VII). Tumor regression studies with strain 2 guinea pigs and syngeneic line 10 hepatocellular carcinoma showed that all fractions were effective when combined with trehalose dimycolates and an additional tumor regression factor (previously designated ACP) and incorporated into oil droplets (78 to 100% cures). A low polar fraction (Fraction IV) was relatively nontoxic [the medium lethal dose for 11-day-old chick embryos inoculated i.v. (CELD50) was more than 10 micrograms] and nonpyrogenic [the dose estimated to give a fever index (area under fever curve) of 40 sq cm in rabbits when 1 hr and 1 degrees are plotted as 1 (FI40) was 5 micrograms] as compared to the unfractionated Lipid A (CELD50 of 0.0546 micrograms; FI40 of 0.046 micrograms). All other fractions were toxic and pyrogenic and caused severe endotoxic shocks when combined with N-acetylmuramyl-L-seryl-D-isoglutamine and injected i.v. into guinea pigs. Fraction IV plus N-acetylmuramyl-L-seryl-D-isoglutamine did not cause endotoxic shock. The phosphate content of Fraction IV was about one-half of that detected in the toxic fractions.

Combined treatment of syngeneic murine tumors and xenotransplanted human lung cancer by immunotherapy and radiotherapy

The synergistic effect of nonspecific immunotherapy with cell-wall skeleton of BCG on radiotherapy against two syngeneic murine tumors, a methylcholanthrene-induced tumor (MCA) and a spontaneous well-differentiated mammary adenocarcinoma (Br-1), was studied in (+/+) balb/c mice and (nu/nu) mice of BALB/c background. Single irradiation of tumors with a dose of 2000 rad induced complete shrinkage in about 18% of MCA and Br-1 tumors in (+/+) mice. Single irradiation did not induce complete shrinkage of tumors in (nu/nu) mice. When immunotherapy was combined with radiotherapy, the rates of complete shrinkage of MCA and Br-1 tumors increased to 82 and 61%, respectively. In contrast, such a strong synergistic effect was not observed in (nu/nu) mice. Moreover, human lung cancers (two squamous cell carcinomas and two small cell carcinomas) xenotransplanted to nude mice were treated with the combined therapy. The effect was stronger on squamous cell carcinomas than on small cell carcinomas.