Adjuvant and antitumour activities of synthetic lipid A analogues

The biological activities of synthetic glycolipids, which were chemically synthesized and based on the structure of lipid A of the lipopolysaccharide (LPS) from Escherichia coli, were examined with special reference to their adjuvant activity on the induction of delayed-type hypersensitivity, activity on the induction of tumour necrotic factor (TNF) and tumour regressive activity on line 10 hepatoma in strain 2 guinea pigs. Among them, a compound structurally corresponding to free E. coli lipid A (compound 506) as well as LPS exhibited potent adjuvant activity in the induction of delayed-type hypersensitivity in guinea pigs and TNF inducing activity in the sera of mice which were presensitized with Propionibacterium acnes. Compound 506 showed potent lethal toxicity in the intravenous administration of BALB/c mice presensitized with P. acnes. The regressive activity on line 10 hepatoma was observed by the multiple intralesional injection of squalane-treated compounds 504 and 505 in strain 2 guinea pigs.

Effect of muramyl dipeptide and its stearoyl derivatives on resistance to Sendai virus infection in mice

The efficacy of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), 6-O-stearoyl-MDP (L18-MDP), N alpha-acetylmuramyl-L-alanyl-D-isoglutaminyl-N epsilon-stearoyl-L-lysine (MDP-Lys-L18) and N-stearoylmuramyl-L-alanyl-D-isoglutamine (2N-L18-MDP) for augmenting host-resistance to viral infection was examined in Sendai virus infected mice. L18-MDP and MDP-Lys-L18 augmented the non-specific host-resistance to infection with Sendai virus. MDP showed a slight enhancement of host-resistance to this infection but 2N-L18-MDP was ineffective. The protective effect of MDP-Lys-L18 was seen only when the drug was administered a few days before the virus challenge. The intranasal administration of MDP-Lys-L18 was effective at 1 microgram but only slight activity was observed in mice treated intravenously or intraperitoneally even at the 100 microgram dose level. MDP-Lys-L18 treatment preceding infection augmented interferon production in the lung of the mice but MDP-Lys-L18 treatment alone induced no interferon.

Structural studies on the linkage unit between poly(N-acetylglucosamine 1-phosphate) and peptidoglycan in cell walls of Bacillus pumilus AHU 1650

Structural studies were carried out on the polymer chains and their linkage regions in two kinds of teichoic acids, poly(N-acetylglucosamine 1-phosphate) [poly(GlcNAc-1-P)] and glycerol teichoic acid, bound to peptidoglycan in the cell walls of Bacillus pumilus AHU 1650. The poly(GlcNAc-1-P)-glycan complex isolated from lysozyme digests of the cell walls contained mannosamine and glycerol as minor components. On the basis of proton NMR spectroscopic data and isolation of N-acetylglucosamine 4-phosphate from acid hydrolysates, the poly(GlcNAc-1-P) was shown to be a polymer in which N-acetylglucosamine 1-phosphate units are joined at C-4 of the glucosamine residues. Mild alkaline hydrolysis of the poly(GlcNAc-1-P)-glycan complex gave a mannosamine-linked glycan fragment and the acidic polymer fraction that contained glycerol residues. Mild acid treatment of the mannosamine-linked glycan fragment gave the linkage disaccharide, ManNAc(beta 1----4)GlcNAc, whereas the acidic polymer fraction was degraded by this treatment into N-acetylglucosamine 4-phosphate and a glycerol-containing fragment characterized as P-(Gro-P)7 (Gro = glycerol). On the other hand, direct mild acid hydrolysis of the complex gave a fragment characterized as P-(Gro-P)7-ManNAc(beta 1----4)GlcNAc. These results lead to a conclusion that in the cell walls the poly(GlcNAc-1-P) chain is attached to peptidoglycan through a linkage unit, (Gro-P)7-ManNAc(beta 1----4)GlcNAc. By means of similar procedures, it was shown that the other cell wall polymer, glycerol teichoic acid, is also attached to peptidoglycan through the same disaccharide, ManNAc(beta 1----4)GlcNAc.

[Decrease of ACh response in isolated duodenum from SART stressed (repeated cold stressed) mice (author's transl)]

ACh response in the isolated duodenum from SART stressed (repeated cold stressed) mice was remarkably decreased in comparison to normal mice 5 days after onset of loading SART stress, and maximal contraction in SART stress mice duodenum was about 37% of that in non-stressed mice. Pilocarpine and KCl responses were also considerably decreased, but BaCl2 response was much the same as in the controls. Thus, the contraction system of the muscle is apparently not damaged by SART stress. Though body weights decreased, the daily intake of food incressed in SART stressed mice. Length of small intestine from SART stressed mice was much the same as in controls, but wet weights of small intestines were larger than in controls. Autonomic agonists, antagonists, tranquilizers and other drugs were given intraperitoneally to mice once daily during SART stress, and the ACh responses in the isolated duodenum were investigated. Pretreatment with adrenergic and anticholinergic drugs inhibited the decrease of ACh response, but antiadrenergic and cholinergic drugs had no effects. Pretreatment with tranquilizers such as reserpine, chlorpromazine, carpipramine and imipramine inhibited the decrease of ACh response in the isolated duodenum, but diazepam, meprobamate and benadryl had no influence. Pretreatment of neurotropin, a neurosedative had good inhibitory effects. Our results suggest that SART stressed mice may be in a state of unbalance regarding sympathetic and parasympathetic nerves, particularly with regard to abnormal tension in the parasympathetic nervous system, in part of duodenum. Pretreatment with most of the above drugs had no influence on loss of body weight in SART stressed mice while pretreatment with neurotropin inhibited body weight to a considerable extent.