Zeitschrift fur Immunitatsforschung, experimentelle und klinische Immunologie最新文献

Previous studies have shown that peptidoglycans from group A and B streptococci inhibit the migration of peritoneal exudate cells from non-sensitized rats and guinea pigs. In the present studies peptidoglycans from S. aureus and S. epidermidis were found to inhibit the migration of cells to the same extent as group A streptococcal peptidoglycan. In contrast, HSA-pentapeptide, an immunologically active synthetic analog of the peptide moiety of peptidoglycan which is free of the intrinsic toxicity of naturally occurring peptidoglycans, did not induce migration inhibition of peritoneal exudate cells from non-sensitized guinea pigs. Sensitization of animals with 200 mug HSA-pentapeptide emulsified in incomplete Freund's adjuvant significantly reduced the inhibitory effect of streptococcal and staphylococcal peptidoglycan; HSA-pentapeptide again showed no activity. However, when HSA-pentapeptide was tested against cells from animals sensitized with 200 mug HSA-pentapeptide incorporated in complete Freund's adjuvant, a strong inhibition of migration was evident. Skin tests performed in these animals, in contrast to the dermonecrotic reaction elicited by streptococcal or staphylococcal peptidoglycan, revealed a characteristic delay hypersensitivity to HSA-pentapeptide.

Rabbits were immunized with synthetic immunogens HSA-(Gly-L-Ala-L-Ala-D-Ala-D-Ala)39 and HSA-(Gly-gamma-D-Glu-L-Ala-D-Ala-D-Ala)40, respectively. Antibodies against HSA-(Gly-L-Ala-L-Ala-D-Ala-D-Ala)39 showed a strong precipitin reaction with the homologous antigen, with HSA-(Gly-gamma-D-Glu-L-Ala-D-Ala-D-Ala)40 and with solubilized peptidoglycan containing peptide subunits with C-terminal D-alanyl-D-alanine. The albumin-peptide conjugates also cross-reacted with rabbit antisera to Streptococcus A-variant, which contain antibodies directed against the peptide moiety of peptidoglycan. The proof for identical determinant groups of peptidoglycan of Streptococcus A-variant and HSA-(Gly-L-Ala-L-Ala-D-Ala-D-Ala)39 was furnished by Ouchterlony gel diffusion studies and by the appropriate inhibition tests of the quantitative precipitin reaction. Immunization of rabbits with HSA-(Gly-gamma-D-Glu-L-Ala-D-Ala-D-Ala)40 yielded antisera which, besides the specificity of antisera to HSA-(Gly-L-Ala-L-Ala-D-Ala-D-Ala)39, showed an additional specificity.

Peptidoglycan is responsible for the endotoxin-like properties of the streptococcus cell wall. The pyrogenic response of rabbit to group A streptococcus peptidoglycan prepared by hot formamide or TCA is dose-dependent and is increased if the material is ultrasonically solubilized. The pyrogenicity can be eliminated by the antiserum to the peptidoglycan or by the degradation of the material by lysozyme. Peptidoglycans prepared from cell walls of group B and L streptococci, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pneumoniae produce fever effects comparable to the response after group A streptococcus peptidoglycan. Spirillum serpens and Escherichia coli contain in addition to endotoxin the peptidoglycan which is also pyrogenic. Repeated injections of bacterial peptidoglycan to rabbit result in tolerance to the fever effect. Cross-tolerance was recorded only exceptionally. Rabbits tolerant to endotoxin respond with a lower fever to S. aureus and group A streptococcus peptidoglycans. Intravenous administration of peptidoglycan to rabbit causes extensive alterations in the heart characterized by various stages of the degenerative and necrotic process. Local Shwartzman reaction can be elicited in rabbit by peptidoglycan used either as a preparative or as a provocative dose in combination with endotoxin, or it can be used for both doses. The results obtained with peptidoglycans prepared from various bacteria are fully comparable. Non-specific resistance of mice to infection induced by streptococcus cell walls was found to be dependent on the peptidoglycan activity; cell wall proteins and polysaccharide are inactive. These properties of peptidoglycan resemble those known from endotoxin studies. The data presented suggest the role of peptidoglycan in pathological reactions resulting from host-parasite interaction.

Purified peptidoglycans isolated from various Gram negative and Gram positive bacteria can substitute for Mycobacteria in Freund's adjuvant. Monomeric subunits possess the same adjuvant activity. This activity seems to be related to the peptidic fraction.

The gelation of a lysate prepared from the amebocytes of Limulus polyphemus, the horseshoe crab, has been used to detect endotoxin-like material in clinical studies and in "in vitro" experiments. The investigation of blood samples from 54 hospitalized patients suspected of having endotoxemia, revealed a positive limulus test in 14. Infections due to gram-positive organisms were not associated with positive assays. These results were in agreement with the observation that living gram-positive microorganisms - in contrast to gram-negative bacteria - did not initiate lysate gelation when studied "in vitro". Only very high concentrations of peptidoglycan, isolated from the cell walls of various gram-positive bacteria, induced the reaction. Therefore, these findings support the view, that the limulus test is relatively specific for the detection of gram-negative bacterial endotoxin and endotoxemia.

Processing of group A and group D streptococcal cell wall was measured after phagocytosis by normal rat peritoneal cells in tissue culture. Group A cell wall was practically non-biodegradable in contrast to group D, which was over 80% degraded by 4-8 days in culture. There was no difference in elimination or degradation of mucopeptide or polysaccharide of group A cell walls. Neither antiserum or sensitized lymphocytes affected persistence. Macrophages from Fisher rats (susceptible to group A cell wall-induced polyarthritis) became cytotoxic for target L-cells 6-7 days after ingestion of group A cell walls. Phagocytosis of group D cell walls induced less cytotoxicity. Macrophages from Buffalo rats (resistant to polyarthritis) were less cytotoxic after phagocytosis of group A cell walls than Fisher macrophages. Soluble cytotoxins could not be detected in macrophage culture media.

Bacterial lipopolysaccharides are negatively charged macromolecules due to the presence of phosphate, pyrophosphate and carboxyl groups. When isolated from bacteria, they are obtained in salt form with metal cations and basic amines. Removal of these ionically bound substances by electrodialysis leads to acidic lipopolysaccharides which on neutralizing with different bases, preparations are obtained which show distinct differences in their physico-chemical properties and in their biological activity. Soluble lipopolysaccharides interact with complement leading to loss of hemolytic activity. This property is embedded in the lipid A part of the molecule and is expressed only when the lipopolysaccharide is present in a favourable particle size. Nevertheless, a number of lipopolysaccharides exists, which, regardless of their particle size do not interact with complement. Lipid A is the part of the molecule responsible for endotoxicity. This was demonstrated by employing solubilized lipid A in complex form with BSA. Soluble lipid A/BSA complexes proved highly toxic for mice and pyrogenic in rabbits, and express many biological activities exhibited by intact lipopolysaccharides. Lipid A, when exposed on the bacterial cell-surface acts as a powerful immunogen, giving rise to the production of specific anti-lipid A antibodies that interact with the lipid A obtained from lipopolysaccharides that are otherwise distinct in their O-serological specificity. Anti-lipid A antibodies occur naturally in the serum of many animals and humans. The biological significance of anti-lipid A antibodies is discussed.

A calculation program is described by means of which the frequency of any type of relationship in cases of disputable descent (questionable partenity, maternity, parenthood, brother- and sisterhood) using blood group results, can be calculated. Within the scope of forensical practice, the program is above all important in cases in which the alleged father and/or mother of the child is deceased, where however, blood group results of other relatives are at disposal, and also in cases of suspected incest - when the alleged father of the child is at the same time father or brother of the child's mother, and, finally, in cases where two men who are related to one another are considered as possible fathers. The program can also be applied to search cases.

This review deals with those biological activities of peptidoglycan that are not directly analogous to the properties of gram-negative bacterial endotoxin. The report is divided into 3 major parts: 1. A survey of peptidoglycan activities such as the induction of inflammatory skin reactions, lesion-enhancing activity (virulence factor), inhibition of phagocytosis of bacteria, inhibition of cell migration, cytotoxicity to mammalian cells, potentiation of the humoral and cellular immune response (adjuvant activity) and enhancement of tumor defense in experimental animals. 2. A presentation of factors which may influence these biological activities of peptidoglycan. 3. A brief discussion of the potential mechanisms of action of peptidoglycan.