Immunological properties of teichoic acids

Adsorption Characterization of Lactobacillus sp. for Di-(2-ethylhexyl) phthalate

Di-(2-ethylhexyl) phthalate (DEHP) is the widely detected plasticizer in foods whose exposure is associated with a myriad of human disorders. The present study focused on identifying Lactobacillus strains with high adsorption potential towards DEHP and further elucidating the mechanism of binding using HPLC, FTIR and SEM. Two strains, Lactobacillus rhamnosus GG and Lactobacillus plantarum MTCC 25,433, were found to rapidly adsorb more than 85% of DEHP in 2 h. Binding potential remained unaffected by heat treatment. Moreover, acid pre-treatment enhanced the DEHP adsorption. Chemical pre-treatments, such as NaIO4, pronase E or lipase, caused reduction in DEHP adsorption to 46% (LGG), 49% (MTCC 25,433) and 62% (MTCC 25,433), respectively, attributing it to cell wall polysaccharides, proteins and lipids. This was also corroborated by stretching vibrations of C = O, N-H, C-N and C-O functional groups. Furthermore, SDS and urea pre-treatment, demonstrated the crucial role of hydrophobic interactions in DEHP adsorption. The extracted peptidoglycan from LGG and MTCC 25,433 adsorbed 45% and 68% of DEHP, respectively, revealing the imperative role of peptidoglycan and its integrity in DEHP adsorption. These findings indicated that DEHP removal was based on physico-chemical adsorption and cell wall proteins, polysaccharides or peptidoglycan played a primary role in its adsorption. Owing to the high binding efficiency, L. rhamnosus GG and L. plantarum MTCC 25,433 were considered to be a potential detoxification strategy to mitigate the risk associated with the consumption of DEHP-contaminated foods.

Efflux Pump (QacA, QacB, and QacC) and β-Lactamase Inhibitors? An Evaluation of 1,8-Naphthyridines against Staphylococcus aureus Strains

The bacterial species Staphylococcus aureus presents a variety of resistance mechanisms, among which the expression of β-lactamases and efflux pumps stand out for providing a significant degree of resistance to clinically relevant antibiotics. The 1,8-naphthyridines are nitrogen heterocycles with a broad spectrum of biological activities and, as such, are promising research targets. However, the potential roles of these compounds on bacterial resistance management remain to be better investigated. Therefore, the present study evaluated the antibacterial activity of 1,8-naphthyridine sulfonamides, addressing their ability to act as inhibitors of β-lactamases and efflux pump (QacA/B and QacC) against the strains SA-K4414 and SA-K4100 of S. aureus. All substances were prepared at an initial concentration of 1024 μg/mL, and their minimum inhibitory concentrations (MIC) were determined by the broth microdilution method. Subsequently, their effects on β-lactamase- and efflux pump-mediated antibiotic resistance was evaluated from the reduction of the MIC of ethidium bromide (EtBr) and β-lactam antibiotics, respectively. The 1,8-naphthyridines did not present direct antibacterial activity against the strains SA-K4414 and SA-K4100 of S. aureus. On the other hand, when associated with antibiotics against both strains, the compounds reduced the MIC of EtBr and β-lactam antibiotics, suggesting that they may act by inhibiting β-lactamases and efflux pumps such as QacC and QacA/B. However, further research is required to elucidate the molecular mechanisms underlying these observed effects.

Propionibacterium acnes-Derived Circulating Immune Complexes in Sarcoidosis Patients

Propionibacterium acnes is a potential etiologic agent of sarcoidosis and a dysregulated immune response to the commensal bacterium is suspected to cause granuloma formation. P. acnes-derived insoluble immune complexes were recently demonstrated in sinus macrophages of sarcoidosis lymph nodes, suggesting local proliferation of the bacterium in affected organs. In the present study, we developed a method for detecting P. acnes-derived immune complexes in human blood by measuring the concentration of P. acnes-specific lipoteichoic acid (PLTA) detectable after an antigen retrieval pretreatment of plasma samples. Before pretreatment, anti-PLTA antibody was detected and PLTA could not be detected, in all plasma samples from 51 sarcoidosis patients and 35 healthy volunteers. After pretreatment, however, a significant level of PLTA (>105 ng/mL) was detected in 33 (65%) sarcoidosis patients and 5 (14%) control subjects, with 86% specificity and 65% sensitivity for sarcoidosis. In both groups, plasma anti-PLTA antibody titers did not differ between samples with and without detection of PLTA. PLTA levels were abnormally increased (>202 ng/mL) in 21 (41%) sarcoidosis patients. These findings suggest that P. acnes-derived circulating immune complexes present in human blood are abnormally increased in many sarcoidosis patients, presumably due to local proliferation of the bacterium in the affected organs.

Detection of Cutibacterium acnes in granulomas of patients with either hypersensitivity pneumonitis or vasculitis reveals that its presence is not unique for sarcoidosis

Granulomas are compact organised structures of different immune cells, including macrophages, lymphocytes and plasma cells, thought to be formed when (foreign) antigens cannot be cleared. The differential diagnosis of a granulomatous lesion is broad and includes infectious aetiologies, malignancy and inflammatory disorders like vasculitis, hypersensitivity pneumonitis and sarcoidosis [1].

Presence of C. acnes in granulomas is not unique to sarcoidosis but can also be found in patients with HP or EGPA. C. acnes may be involved in the pathogenesis of those granulomatous diseases in a mitogenic way.https://bit.ly/3pU0PeC

Chaptalia nutans Polak: Root Extract Has High In Vitro Antioxidant Activity and Low Cytotoxicity In Vivo

The Asteraceae family is widely known for its therapeutic, aromatic, and nutritional properties. Chaptalia nutans (C. nutans), a member of the family, is widely used in folk medicine in southern Brazil. In this study, we aim to assess compounds present in root extracts of C. nutans, and evaluate their antioxidant capacity and toxicity. To determine the chemical composition of the extract, was performed through Liquid Chromatography coupled with Mass Spectroscopy. Antioxidant capacity, toxicity (Artemia salina biosassay), cytotoxicity, genotoxicity (Allium cepa test), and neurotoxicity (Drosophila melanogaster model) were evaluated. A large number of bioactive phytoconstituents were determined to be present, such as alkaloids, coumarins, flavonoids, terpenes, and especially phenolic compounds, which may explain the antioxidant capacity of the extract. Extracts had the capacity to protect cells from protein and lipid damage, and inhibit the formation of oxygen radicals. The A. salina bioassay revealed that extracts were only slightly toxic. In A. cepa, cells exposed to 1.5 mg/mL extract were protected against chromosomal damage caused by glyphosate, and had mitotic index values that were reduced by 49%. A concentration of 10 mg/mL extract did not kill flies, and when coadministered with paraquat (PQ) (52.5%) produced a mortality rate of only 18.75%. These findings indicated that the extract had the potential to protect against PQ-induced neurotoxicity. Taken together, these data reveal for the first time that the root extract of C. nutans is a rich source of natural antioxidants. The extract may be useful in the food and pharmaceutical industries.

Staphylococcus aureus Toxins and Their Molecular Activity in Infectious Diseases

Staphylococcus aureus is a microorganism resident in the skin and nasal membranes with a dreadful pathogenic potential to cause a variety of community and hospital-acquired infections. The frequency of these infections is increasing and their treatment is becoming more difficult. The ability of S. aureus to form biofilms and the emergence of multidrug-resistant strains are the main reasons determining the challenge in dealing with these infections. S. aureus' infectious capacity and its success as a pathogen is related to the expression of virulence factors, among which the production of a wide variety of toxins is highlighted. For this reason, a better understanding of S. aureus toxins is needed to enable the development of new strategies to reduce their production and consequently improve therapeutic approaches. This review focuses on understanding the toxin-based pathogenesis of S. aureus and their role on infectious diseases.

Anti-arthritic activity of cell wall content of Lactobacillus plantarum in freund's adjuvant-induced arthritic rats: involvement of cellular inflammatory mediators and other biomarkers

Alteration of microbiota is related with rheumatoid arthritis (RA) and administration of certain probiotics showed an improvement in RA. The present study was designed to find out the anti-arthritic activity of cell wall content of Lactobacillus plantarum in complete Freund's adjuvant (CFA)-induced arthritis in rats. Freund's adjuvant was injected into the left footpad in female rats on day 0 and dexamethasone (1 mg kg^-1, s.c.) & cell wall content of L. plantarum (10⁵, 10⁷, and 10⁹ cfu/animal, s.c.) treatment were given from day 7 to 21. The change in body weight, paw volume and arthritic index, joint stiffness, gait test, mobility test, erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP) level, serum rheumatoid factor (RF), and serum TNF-α was measured on day 21. Cell wall content of L. plantarum treated animals showed improvement in all the parameters as compared to that in CFA-treated animals and exert anti-arthritic activity.

18 GHz electromagnetic field induces permeability of Gram-positive cocci

The effect of electromagnetic field (EMF) exposures at the microwave (MW) frequency of 18 GHz, on four cocci, Planococcus maritimus KMM 3738, Staphylococcus aureus CIP 65.8(T), S. aureus ATCC 25923 and S. epidermidis ATCC 14990(T), was investigated. We demonstrate that exposing the bacteria to an EMF induced permeability in the bacterial membranes of all strains studied, as confirmed directly by transmission electron microscopy (TEM), and indirectly via the propidium iodide assay and the uptake of silica nanospheres. The cells remained permeable for at least nine minutes after EMF exposure. It was shown that all strains internalized 23.5 nm nanospheres, whereas the internalization of the 46.3 nm nanospheres differed amongst the bacterial strains (S. epidermidis ATCC 14990(T) ~  0%; Staphylococcus aureus CIP 65.8(T) S. aureus ATCC 25923, ~40%; Planococcus maritimus KMM 3738, ~ 80%). Cell viability experiments indicated that up to 84% of the cells exposed to the EMF remained viable. The morphology of the bacterial cells was not altered, as inferred from the scanning electron micrographs, however traces of leaked cytosolic fluids from the EMF exposed cells could be detected. EMF-induced permeabilization may represent an innovative, alternative cell permeability technique for applications in biomedical engineering, cell drug delivery and gene therapy.

Novel synthetic (poly)glycerolphosphate-based antistaphylococcal conjugate vaccine

Staphylococcal infections are a major source of global morbidity and mortality. Currently there exists no antistaphylococcal vaccine in clinical use. Previous animal studies suggested a possible role for purified lipoteichoic acid as a vaccine target for eliciting protective IgG to several Gram-positive pathogens. Since the highly conserved (poly)glycerolphosphate backbone of lipoteichoic acid is a major antigenic target of the humoral immune system during staphylococcal infections, we developed a synthetic method for producing glycerol phosphoramidites to create a covalent 10-mer of (poly)glycerolphosphate for potential use in a conjugate vaccine. We initially demonstrated that intact Staphylococcus aureus elicits murine CD4(+) T cell-dependent (poly)glycerolphosphate-specific IgM and IgG responses in vivo. Naive mice immunized with a covalent conjugate of (poly)glycerolphosphate and tetanus toxoid in alum plus CpG-oligodeoxynucleotides produced high secondary titers of serum (poly)glycerolphosphate-specific IgG. Sera from immunized mice enhanced opsonophagocytic killing of live Staphylococcus aureus in vitro. Mice actively immunized with the (poly)glycerolphosphate conjugate vaccine showed rapid clearance of staphylococcal bacteremia in vivo relative to mice similarly immunized with an irrelevant conjugate vaccine. In contrast to purified, natural lipoteichoic acid, the (poly)glycerolphosphate conjugate vaccine itself exhibited no detectable inflammatory activity. These data suggest that a synthetic (poly)glycerolphosphate-based conjugate vaccine will contribute to active protection against extracellular Gram-positive pathogens expressing this highly conserved backbone structure in their membrane-associated lipoteichoic acid.

Microbiota, innate immune system, and gastrointestinal muscle: ongoing studies

AIM

To test the activities of culture-extracted or commercially available toll-like receptors (TLRs) ligands to establish their direct impact on target gastrointestinal motor cells.

METHODS

Short-term and long-term effects of Shigella flexneri M90T and Escherichia coli K-2 strains-extracted lipopolysaccharides (LPS), commercially highly purified LPS (E. coli O111:B4 and EH100), and Pam2CSK4 and Pam3CSK4, which bind TLR2/6 and TLR1/2 heterodimers, respectively, have been assessed on pure primary cultures of colonic human smooth muscle cells (HSMC).

RESULTS

Pathogenic Shigella-LPS and nonpathogenic E. coli K-2-LPS induced a time-dependent decrease of resting cell length and acetylcholine-induced contraction, with both alterations occurring rapidly and being more pronounced in response to the former. However, their effects differed, prolonging HSMC exposure with Shigella-LPS effects maintained throughout the 4 hours of observation compared with E. coli K-2-LPS, which disappeared after 60 minutes of incubation. Similar differences in magnitude and time dependency of myogenic effects were observed between pure TLR4 and TLR2/1 or TLR2/6 ligands. The specific activation of TLR4 with LPS from pathogen or nonpathogen E. coli, O111:B4 and EH100, respectively, induced smooth muscle alterations that progressively increased, prolonging incubation, whereas TLR2 ligands induced short-term alterations, of a lesser magnitude, which decreased over time. The real-time polymerase chain reaction analysis showed that HSMC express mRNA for TLR1, 2, 4, and 6, substantiating a direct effect of TLR ligands on human colonic smooth muscle.

CONCLUSIONS

This study highlights that bacterial products can directly affect gastrointestinal motility and that TLRs subtypes may differ in their cellular activity.

A continuum of anionic charge: structures and functions of D-alanyl-teichoic acids in gram-positive bacteria

Teichoic acids (TAs) are major wall and membrane components of most gram-positive bacteria. With few exceptions, they are polymers of glycerol-phosphate or ribitol-phosphate to which are attached glycosyl and D-alanyl ester residues. Wall TA is attached to peptidoglycan via a linkage unit, whereas lipoteichoic acid is attached to glycolipid intercalated in the membrane. Together with peptidoglycan, these polymers make up a polyanionic matrix that functions in (i) cation homeostasis; (ii) trafficking of ions, nutrients, proteins, and antibiotics; (iii) regulation of autolysins; and (iv) presentation of envelope proteins. The esterification of TAs with D-alanyl esters provides a means of modulating the net anionic charge, determining the cationic binding capacity, and displaying cations in the wall. This review addresses the structures and functions of D-alanyl-TAs, the D-alanylation system encoded by the dlt operon, and the roles of TAs in cell growth. The importance of dlt in the physiology of many organisms is illustrated by the variety of mutant phenotypes. In addition, advances in our understanding of D-alanyl ester function in virulence and host-mediated responses have been made possible through targeted mutagenesis of dlt. Studies of the mechanism of D-alanylation have identified two potential targets of antibacterial action and provided possible screening reactions for designing novel agents targeted to D-alanyl-TA synthesis.

Tissue reactions to a component of root canal system bacteria: lipoteichoic acid

Lipoteichoic acid (LTA), present in Gram-positive microorganisms, has physiochemical characteristics that allow it to act as an immunogen. Due to polymicrobial characteristics of root canal infections, LTA can participate in the development of periapical disease. The reaction of the rat subcutaneous tissue to Teflon tube implants, filled with Fibrinol soaked in lipoteichoic acid (concentration of 150 microg/ml), was observed. Lipoteichoic acid provoked an inflammatory tissue reaction.

Cell wall teichoic acids of Actinomadura viridis VKM Ac-1315T

The cell walls of Actinomadura viridis contain poly(glycosylglycerol phosphate) chains of complex structure. On the basis of NMR spectroscopy of the polymer and glycosides thereof the following structural units were found: beta-D-Galp3Me-(1-->4)[beta-D-Glcp-(1-->6)]-beta-D-Galp-(1-->1)-++ +snGro (G1); beta-D-Galp-(1-->4)-beta-D-Galp-(1-->1)-snGro (G2); beta-D-Galp3Me-(1-->4)-beta-D-Galp-(1-->1)-snGro (G2a); beta-D-Galp-(1-->1)-snGro (G3); beta-D-Galp-(1-->1)[beta-D-Galp-(1-->2)]-snGro (G4); beta-D-Glcp-(1-->2)-snGro (G5). Glycosides G1, G2 and G3 were the predominant components of the teichoic acid: they formed the polymer chain via phosphodiester bonds involving C-3 of the glycerol residue and C-3 of the galactosyl residue which in turn glycosylates C-1 of the glycerol residue. Whether the different glycosides make up the one chain or whether there are several poly(glycosylglycerol phosphate) chains in the cell wall remains to be determined. It was suggested that the minor component G5 is located at the nonterminal end of the chains. Compound G4 which contains disubstituted glycerol residues (unusual for the teichoic acid) was also found as a minor component; this may be the glycoside of a new type of teichoic acid, or a glycoside on the terminal end of the above mentioned chains. In addition, small amounts of 1,3-poly(glycerol phosphate) chains were found in the cell wall.

Structure of an antigenic teichoic acid shared by clinical isolates of Enterococcus faecalis and vancomycin-resistant Enterococcus faecium

A shared antigenic teichoic acid, previously found to be a surface capsule-like polysaccharide, was isolated from clinical isolates of Enterococcus faecalis and vancomycin-resistant E. faecium. It was composed of glucose, glycerol, and phosphate as determined by chemical and GC-MS analysis. The repeating-unit structure was elucidated by a series of 1H, 13C, and 31P NMR spectroscopy to be the following: [formula: see text]

Cell surface-associated lipoteichoic acid acts as an adhesion factor for attachment of Lactobacillus johnsonii La1 to human enterocyte-like Caco-2 cells

The influence of pH on the adhesion of two Lactobacillus strains to Caco-2 human intestinal cells was investigated. One strain, Lactobacillus johnsonii La1, was adherent at any pH between 4 and 7. The other one, L. acidophilus La10, did not attach to this cell line under the same experimental conditions. On the basis of these results, we used the monoclonal antibody technique as a tool to determine differences on the surface of these bacteria and to identify a factor for adhesion. Mice were immunized with live La1, and the hybridomas produced by fusion of spleen cells with ONS1 cells were screened for the production of antibodies specific for L. johnsonii La1. A set of these monoclonal antibodies was directed against a nonproteinaceous component of the L. johnsonii La1 surface. It was identified as lipoteichoic acid (LTA). This molecule was isolated, chemically characterized, and tested in adhesion experiments in the same system. The adhesion of L. johnsonii La1 to Caco-2 cells was inhibited in a concentration-dependent way by purified LTA as well as by L. johnsonii La1 culture supernatant that contained LTA. These results showed that the mechanism of adhesion of L. johnsonii La1 to human Caco-2 cells involves LTA.

Polyphasic taxonomy, a consensus approach to bacterial systematics

Over the last 25 years, a much broader range of taxonomic studies of bacteria has gradually replaced the former reliance upon morphological, physiological, and biochemical characterization. This polyphasic taxonomy takes into account all available phenotypic and genotypic data and integrates them in a consensus type of classification, framed in a general phylogeny derived from 16S rRNA sequence analysis. In some cases, the consensus classification is a compromise containing a minimum of contradictions. It is thought that the more parameters that will become available in the future, the more polyphasic classification will gain stability. In this review, the practice of polyphasic taxonomy is discussed for four groups of bacteria chosen for their relevance, complexity, or both: the genera Xanthomonas and Campylobacter, the lactic acid bacteria, and the family Comamonadaceae. An evaluation of our present insights, the conclusions derived from it, and the perspectives of polyphasic taxonomy are discussed, emphasizing the keystone role of the species. Taxonomists did not succeed in standardizing species delimitation by using percent DNA hybridization values. Together with the absence of another "gold standard" for species definition, this has an enormous repercussion on bacterial taxonomy. This problem is faced in polyphasic taxonomy, which does not depend on a theory, a hypothesis, or a set of rules, presenting a pragmatic approach to a consensus type of taxonomy, integrating all available data maximally. In the future, polyphasic taxonomy will have to cope with (i) enormous amounts of data, (ii) large numbers of strains, and (iii) data fusion (data aggregation), which will demand efficient and centralized data storage. In the future, taxonomic studies will require collaborative efforts by specialized laboratories even more than now is the case. Whether these future developments will guarantee a more stable consensus classification remains an open question.

Molecular and structural requirements of a lipoteichoic acid from Enterococcus hirae ATCC 9790 for cytokine-inducing, antitumor, and antigenic activities

Comparison was made between the immunobiological and antigenic properties of two lipoteichoic acid (LTA) fractions (LTA-1 and -2) from Enterococcus hirae ATCC 9790, their glycolipid portions, and synthetic compounds partially mimicking the above bacterial products. The more lipophilic LTA-2 fraction was capable of inducing serum tumor necrosis factor alpha and interleukin-6 in muramyldipeptide-primed mice and serum gamma interferon in those primed with Propionibacterium acnes. The LTA-2 fraction also induced tumor necrosis factor alpha, interleukin-6, and thymocyte-activating factor (essentially interleukin-1) in murine peritoneal macrophage cultures. Consecutive intravenous injections of muramyldipeptide and the LTA-2 fraction in Meth A fibrosarcoma-bearing BALB/c mice caused hemorrhagic necrosis and marked regression leading to complete regression of the tumor with no accompanying weakening or lethal effects. The LTA-2 fraction was at least 10,000-fold less pyrogenic in rabbits than a reference endotoxic lipopolysaccharide. The more hydrophilic LTA-1 fraction, on the other hand, showed at most marginal activity in the in vivo and in vitro assays. Natural glycolipids (NGL-1 and -2) which were prepared from a chloroform-methanol extract of Streptococcus pyogenes and E. hirae cells, and comparable in structure to the lipid moieties of the LTA-1 and -2 fractions, respectively, were practically inactive in all of the assays. None of the test synthetic compounds was immunobiologically active, although synthetic partial counterparts of the structure of LTA proposed by W. Fischer (Handb. Lipid Res. 6:123-234, 1990) reacted with murine monoclonal antibody TS-2, which was raised against OK-432, a penicillin-killed S. pyogenes preparation, and capable of neutralizing the cytokine-inducing activities of the LTA-2 fraction.

Thymocyte proliferation and maturation in response to staphylococcal lipoteichoic acid

Lipoteichoic acid (LTA) from Staphylococcus saprophyticus strain S1 could be shown to induce thymocyte proliferation and maturation in BALB/c-mice after systemic administration. The increase in thymocyte numbers per mg organ weight was statistically significant. Determination of thymic lymphatic subsets revealed a considerable up-regulation of mature cells expressing helper/inducer (L3T4) or cytotoxic/suppressor (Lyt-2) phenotypes. Thus administration of staphylococcal LTA obviously accelerated murine thymocyte proliferation and maturation. Counts of BALB/c-mouse peripheral blood lymphocytes (PBL) revealed no evident fluctuation within one week after LTA administration, however, statistically significant increases could be detected two weeks after treatment. The determination of activated PBL expressing IL-2 receptors suggested that injection of staphylococcal LTA apparently induced an immunostimulation since those cells were significantly enhanced within one week after LTA administration.

Staphylococcal lipoteichoic acid exerts growth factor-like activity towards human and murine cells

Lipoteichoic acid (LTA) was extracted from Staphylococcus saprophyticus strain S1 and tested for the capacity to induce hematopoietic and lymphatic cell proliferation. As compared to nontreated cells, the number of human bone marrow cells significantly increased in the presence of low LTA concentrations. Optimal growth was observed on the fifth day of in vitro incubation. After exposure to LTA, the lymphocyte proliferation rate also increased in a dose and time dependent manner. On the other hand, human epithelial cells and fibroblasts did not show enhanced growth activities in the presence of LTA.

Activation of mononuclear immune cells in response to staphylococcal lipoteichoic acid

The goal of the present study was to evaluate the influence of staphylococcal lipoteichoic acid (LTA) on the activation of mononuclear immune cells. A murine tumor necrosis-like factor (TNF-like) was induced in the sera of CD-1 mice which had been primed with heat/formalin-inactivated Propionibacterium avidum KP-40 and subsequently exposed to LTA extracted from Staphylococcus saprophyticus strain S 1. Monoclonal antibody against murine TNF (anti-TNF) significantly inhibited the cytostatic activity of mice sera against transformed L-929 cells. Freshly isolated lymphocytes did not display interleukin 2 (Il-2) receptors, but receptors were expressed on Con A incubated cells and in significantly higher numbers after coexposure to staphylococcal LTA in vitro. Since the induction of TNF (macrophages) and Il-2 receptors (lymphocytes) represent stimulation of the mononuclear immune system, staphylococcal LTA may be considered to be an immunomodifier.

Biological properties of staphylococcal lipoteichoic acid and related macromolecules

Lipoteichoic acids (LTAs) and related macromolecules (e.g. cell surface substance, CSS; cell surface antigen, CSA; cell surface complex, CSC) are a group of phosphate-containing polymers associated with the cell walls of Gram-positive bacteria (32). They may be considered as surface-reactive antigens (immunogens, biological response modyfiers) as well as membrane components which mediate the attachment of certain bacteria (S. saprophyticus, S. aureus, group A streptococci) to host cell tissues.

Serum antibodies to pathogenic actinomycetes in the normal human population

Sera of persons without known actinomycotic infection (n = 153) were tested for antibodies reacting with antigenic preparations of different Actinomyces spp. and Nocardia spp. By using an enzyme immunoassay, 16% of all of the sera analyzed reacted significantly with antigens of A. viscosus and 2% those of with A. naeslundii. The antigens detected by these antibodies were of low molecular mass (14-32 kDa) and showed a uniform reaction pattern in the immunoblot analysis. Multiple bands coccurred with a difference of approximately 2 kDa in size suggesting the presence of repetitive units. Analogous antibodies were not observed with A. israelii serovar 1 and serovar 2 antigens, which were only insignificantly bound by the sera. The antibodies demonstrated were most probably acquired during episodes of periodontal disease or gingivitis in which A. viscosus is etiologically involved. Antibodies against nocardial antigens were not demonstrated in significant proportions by enzyme immunoassay and immunoblot analysis.

Antibodies to staphylococcal peptidoglycan and its peptide epitopes, teichoic acid, and lipoteichoic acid in sera from blood donors and patients with staphylococcal infections

Antibodies to the staphylococcal antigens peptidoglycan, beta-ribitol teichoic acid, and lipoteichoic acid, as well as to the peptidoglycan epitopes L-Lys-D-Ala-D-Ala, L-Lys-D-Ala, and pentaglycine, were found over a wide range of concentrations in sera from both blood donors and patients with verified or suspected staphylococcal infections. The patient group was heterogeneous with regard to both age and type of staphylococcal infections, being representative for sera sent to our laboratory. In single-antigen assays antibodies to pentaglycine had the highest predictive positive value (67%), although only 32% of the patients had elevated levels of such antibodies. Combinations of test antigens could yield positive predictive values as high as 100%, but then the fraction of positive sera was low. Indeed, the fraction of patient sera which was positive in multiple-antigen tests never exceeded 61%. The clinical usefulness of these seroassays for identifying Staphylococcus aureus as a causative agent was limited, owing to the considerable overlap in the range of antibody concentrations between patient and blood donor sera.

Interaction of streptococcal lipoteichoic acid with artificial tooth pellicle

Artificial pellicles were prepared by coating hydroxyapatite beads with whole saliva. Radiolabelled lipoteichoic acid was isolated from Streptococcus sanguis NCTC 7863 by phenol extraction. Various concentrations of radiolabelled lipoteichoic acid were mixed with saliva-coated hydroxyapatite in the presence and absence of high ionic strength phosphate buffer, bovine serum albumin, gelatin, unlabelled lipoteichoic acid, Tween 20 and Triton X-100. The amount of lipoteichoic acid binding was measured by counting the residual radioactivity of the saliva-coated hydroxyapatite after thorough washing. In one experiment the binding was measured in the presence of a mucinous glycoprotein isolated from human saliva. The data were analysed by means of Scatchard and double reciprocal plots of the bound and unbound fraction of lipoteichoic acid. The lipoteichoic acid interacted hydrophobically with the saliva-coated hydroxyapatite; the interaction was complex with multiple binding sites exhibiting a range of affinities. The mean association constant was 1.1 x 10(9) M-1 and the minimum number of binding sites was 3.9 x 10(12)/mm2 of artificial pellicle. The salivary mucin competitively inhibited the interaction, which suggests that this may be one of the salivary components involved.

Structure and glycosylation of lipoteichoic acids in Bacillus strains

The occurrence, structure, and glycosylation of lipoteichoic acids were studied in 15 Bacillus strains, including Bacillus cereus (4 strains), Bacillus subtilis (5 strains), Bacillus licheniformis (1 strain), Bacillus polymyxa (2 strains), and Bacillus circulans (3 strains). Whereas in the cells of B. polymyxa and B. circulans neither lipoteichoic acid nor related amphipathic polymer could be detected, the cells of other Bacillus strains were shown to contain lipoteichoic acids built up of poly(glycerol phosphate) backbone chains and hydrophobic anchors [gentiobiosyl(beta 1----1/3)diacylglycerol or monoacylglycerol]. The lipoteichoic acid chains of the B. licheniformis strain and three of the B. subtilis strains had N-acetylglucosamine side branches, but those of the B. cereus strains and the remaining two B. subtilis strains did not. The membranes of the B. licheniformis strain and the first three B. subtilis strains exhibited enzyme activities for the synthesis of beta-N-acetylglucosamine-P-polyprenol and for the transfer of N-acetylglucosamine from this glycolipid to endogenous acceptors presumed to be lipoteichoic acid precursors. In contrast, the membranes of the other strains lacked both or either of these two enzyme activities. The correlation between the occurrence of N-acetylglucosamine-linked lipoteichoic acids and the distribution of these enzymes is consistent with the previously proposed function of beta-N-acetylglucosamine-P-polyprenol as a glycosyl donor in the introduction of alpha-N-acetylglucosamine branches to lipoteichoic acid backbone chains.

Lipoteichoic acid-antilipoteichoic acid complexes induce superoxide generation by human neutrophils

Human neutrophils (PMNs) which have been incubated with lipoteichoic acid (LTA) from group A streptococci generated large amounts of superoxide (O2- chemiluminescence and hydrogen peroxide when challenged with anti-LTA antibodies. Cytochalasin B further enhanced O2- generation. The onset of O2- generation by the LTA-anti-LTA complexes was much faster than that induced by BSA-anti-BSA complexes. LTA-treated PMNs generated much less O2- when challenged with BSA complexes, suggesting that LTA might have blocked, nonspecifically, some of the Fc receptors on PMNs. PMNs treated with LTA-anti-LTA complexes further interacted with bystander nonsensitized PMNs resulting in enhanced O2- generation, suggesting that small numbers of LTA-sensitized PMNs might recruit additional PMNs to participate in the generation of toxic oxygen species. Protelolytic enzyme treatment of PMNs further enhanced the generation of O2- by PMNs treated with LTA-anti-LTA. Superoxide generation could also be induced when PMNs and anti-LTA antibodies interacted with target cells (fibroblasts, epithelial cells) pretreated with LTA. This effect was also further enhanced by pretreatment of the target cells with proteases. PMNs incubated with LTA released lysosomal enzymes following treatment with anti-LTA antibodies. The amounts of phosphatase, beta-glucoronidase, N-acetylglucosaminidase, mannosidase, and lysozyme release by LTA-anti-LTA complexes were much smaller than those released by antibody or histone-opsonized streptococci, suggesting that opsonized particles are more efficient lysosomal enzyme releasers. However, since the amounts of O2- generated by the LTA complexes equaled those generated by the opsonized particles, it is assumed that the signals for triggering a respiratory burst and lysosomal enzyme secretion might be different. Generation of O2- by LTA complexes was strongly inhibited by lipoxygenase inhibitors but not by cyclooxigenase inhibitors. Also phenylbutazone, trifluorperazine, and DASA markedly inhibited O2- generation induced by LTA complexes. These data suggest that bacterial products in the presence of antibody might have important biological effects on phagocytic cells and that these effects may be inimical to the host.

Bacterial antigen immunolabeling in macrophages after phagocytosis and degradation of Bacillus subtilis

After phagocytosis of Bacillus subtilis 168 by bone marrow-derived macrophages, the intracellular pathway followed by different antigens was studied by immunofluorescence and immunoelectron microscopy. Three different rabbit antisera were used: (i) an antiserum to B. subtilis whole cells mainly recognizing the cell wall constituents, (ii) an antiserum to teichoic acid, and (iii) an antiserum to peptidoglycan recognizing the disaccharide tetrapeptide molecules resulting from peptidoglycan degradation. During the first 3 h after phagocytosis of B. subtilis, the three antisera were confined to the same vacuolar compartments, as follows. They were first found in phagosomes gathered in the perinuclear region. Upon bacterial degradation, the three antisera colocalized in an increasing number of small dense vesicles, located in the perinuclear region, that seemed to result from the fragmentation of phagolysosomes. These vesicles correspond to an acidic compartment since they also stained for 3-(2,4-dinitroanilino)-3'-amino-N-methyldipropylamine, a drug known to accumulate in the acidic compartments of cells. At later time points, the antigens recognized by the three antisera followed different pathways. After 18 h, teichoic acid and peptidoglycan were no longer detectable in macrophages whereas an antigen(s) labeled with antiserum to B. subtilis whole cells remained stocked for several days in small acidic vesicles randomly distributed throughout the macrophage. This compartment appeared to be different from the one labeled during the first 3 h after ingestion of bacteria. These results suggest that the transport rate and the compartments implicated in antigen processing differ according to the antigen.

Production of potent polyclonal antibodies to bacterial membrane amphiphiles

Lipid A (LA), ketodeoxyoctonate (KDO) and lipoteichoic acids (LTA) were used to produce homologous polyclonal antibodies. These haptens were administered to rabbits in differing immunogenic forms, using multiple intradermal and intraperitoneal injections with complete Freund adjuvant. Booster injections were either made intradermally with incomplete Freund adjuvant or intravenously in saline. The immune-response was monitored regularly with an enzyme-immunoassay. Lipid A and KDO covalently linked to bovine serum albumin (BSA), with hapten densities per BSA molecule of 17 and 9, respectively, produced nondetectable immune-response. Acid-hydrolysed and intact cells of Salmonella minnesota Re 595 used as LA and KDO immunogens, respectively, produced significant immune-response when administered intradermally or intraperitoneally. Good immune-response was obtained with LTA covalently linked to BAS. However, a better result was obtained with crude LTA, containing 21.5% proteins. Generally, the lengthy immunization schedules used produced IgG antibodies to the antigens and the highest reciprocal titres attained were 75,000, 55,000 and 150,000 for LA, KDO and LTA, respectively. Meaningful expression of antisera titres by enzyme-immunoassay is discussed. We defined titre as the reciprocal antiserum dilution of the intercept of the mid-point on the linear section ending at 0.2 absorbance on the antiserum dilution curve.

Nuclear magnetic resonance spectra of lipoteichoic acid

Lipoteichoic acid acids with a range of chemical compositions have been studied using 1H; 13C- and 31P-nuclear magnetic resonance. Proton spectroscopy provided a rapid method for demonstrating whether alanine in a sample is covalently bound to the polyglycerophosphate chains and for monitoring hydrolysis of alanine. The nature of sugar substituents can be determined, with some limitations, from the 13C spectra, and the proportions of glycerol residues substituted by alanine and sugar can be measured. The 31P spectra of lipoteichoic acid provided information about both the degree of substitution and the distribution of the substituent along the polyglycerophosphate chain, except when the substituent was galactose. The polyglycerophosphate chains were shown to undergo rapid internal rotation and no evidence for tertiary structure was found either in the presence or absence of magnesium ions. Magnesium ions exchange rapidly between the bound and free state and the binding constant to lipoteichoic acid of 64 M-1 is typical for monophosphates in aqueous solution. There was no evidence that alanine substitution affects the binding constant for magnesium ions.

Antibodies to various bacterial cell wall peptidoglycans in human and rabbit sera

Sera from patients with verified systemic staphylococcal infection contained antibodies reactive with peptidoglycan (PG) from Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Micrococcus lysodeikticus, Bacillus subtilis, and Escherichia coli. The presence of anti-PG cross-reactive antibodies was verified in patient sera by inhibition studies with the various bacterial PGs. Antibodies to nonstaphylococcal PGs were also elevated in sera from rabbits immunized with S. aureus PG. Antibodies to S. aureus PG were removed with the synthetic peptide analogs of S. aureus PG, the L-Lys-D-Ala-D-Ala, L-Lys-D-Ala, and (Gly)5 determinants, as well as with an S. aureus PG peptide fragment containing the determinants D-Ala-D-Ala and L-Lys-D-Ala. Isolated antibodies to the PG peptides, both synthetic and native, were reactive with S. aureus and S. epidermidis PGs. The antibodies to the D-Ala-D-Ala and the L-Lys-D-Ala determinants were also reactive with S. pyogenes PG, but not with PGs from M. lysodeikticus, B. subtilis, and E. coli.

The ability to sensitize host cells for destruction by autologous complement is a general property of lipoteichoic acid

Previous studies have demonstrated that lipoteichoic acid (LTA) from Streptococcus pneumoniae binds to erythrocytes and renders them susceptible to lysis by autologous complement. The present study was performed to determine whether LTA from two other gram-positive bacterial species had the ability to render mammalian cells susceptible to lysis by autologous complement. Human erythrocytes were sensitized with LTA from S. pneumoniae, Streptococcus pyogenes, or Lactobacillus fermentum. Under incubation in normal autologous serum, lysis was observed with each of the LTA-sensitized erythrocyte preparations. When erythrocytes from a C2-deficient patient were sensitized with the LTA preparations and then incubated in autologous, C2-deficient serum, the erythrocytes sensitized with S. pyogenes or L. fermentum LTA demonstrated relatively little lysis, whereas the erythrocytes sensitized with S. pneumoniae LTA yielded near-total lysis. After reconstitution of the C2-deficient serum with purified human C2, lysis was observed with all three LTA preparations. When erythrocytes from an agammaglobulinemic patient were sensitized with either the S. pyogenes or the L. fermentum LTA, they were not lysed in the presence of autologous agammaglobulinemic serum, whereas the erythrocytes sensitized with S. pneumoniae LTA were completely lysed. Serum obtained from the agammaglobulinemic patient after reconstitution with intravenous pooled gamma globulin was able to lyse autologous erythrocytes sensitized with each of the three LTA preparations. These results demonstrate that the ability to render host cells susceptible to lysis by autologous complement is a general property of LTA. Whether activation of the autologous complement occurs by the classical or alternative pathways and whether it is antibody dependent depends on the nature of the bacterial LTA.

Structural studies on lipoteichoic acids from four Listeria strains

The lipoteichoic acids were isolated from phenol extracts of four Listeria strains representing serotypes 4a, 4b, 6a, and 6 to compare the differences in structure of amphiphilic polysaccharides from various serotypes of Listeria spp. The lipoteichoic acids from the four strains examined had the same structure in both hydrophilic chains and lipid portions. On the basis of the results of nuclear magnetic resonance spectroscopy and Smith degradation, the hydrophilic chains were shown to be 1,3-linked poly(glycerol phosphate) in which some of the glycerol residues had alpha-galactosyl substituents. The lipid portions were released by treatment with 46% hydrogen fluoride or 98% acetic acid. They were determined to be 3(1)-(2'-O-alpha-D-galactopyranosyl-alpha-D-glucopyranosyl)-1(3), 2-diacylglycerol and 3(1)-[6'-phosphatidyl-2'-O-(alpha-D-galactopyranosyl)-alpha- D-glucopyranosyl]-1(3),2-diacylglycerol. The degrees of glycosyl substitution and proportions of the two lipids varied to some extent among these four strains.

Structure of the serine-containing capsular polysaccharide K40 antigen from Escherichia coli O8:K40:H9

The structure of the K40 antigenic capsular polysaccharide (K40 antigen) of E. coli O8:K40:H9 was elucidated by determination of the composition, 1H- and 13C-n.m.r. spectroscopy, periodate oxidation and Smith degradation, and methylation analysis. The K40 polysaccharide consists of [(O-beta-D-glucopyranosyluronic acid)-(1----4)-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1----6)-O -(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1----4)] repeating units. All of the glucuronic acid residues are substituted amidically with L-serine.

Antibodies to liposomes, phospholipids and phosphate esters

Polyclonal and monoclonal antibodies to liposomes having various phospholipid compositions have been produced. Binding of the anti-lipid bilayer antibodies is influenced both by the chemical composition and the physical state of the liposomal lipids. The antibodies to liposomes have a 'subsite' in the binding site that recognizes small soluble phosphorylated haptens such as nucleotides (e.g., ATP). The capacity of anti-liposome antibodies to bind to phosphate is also shared by antibodies to numerous other substances, including lipid A from Gram-negative bacterial lipopolysaccharide, cardiolipin, DNA, polynucleotides, and lipoteichoic acids from Gram-positive bacteria. Because of similarities of chemical structures between all of these molecules widespread immunological cross-reactivities are observed.

Antibodies to lipoteichoic acid from Staphylococcus aureus. Specificity of murine monoclonal and human antibodies

Two monoclonal antibodies against staphylococcal lipoteichoic acid (LTA) were made by fusing P3X63Ag8 myeloma cells and splenocytes from mice immunized with purified LTA. Both were isotyped as being IgM kappa. Their specificities were determined by enzyme-linked immunosorbent assays indicating that both antibodies reacted with the glycerol-phosphate backbone, while one of them also had some affinity for the alanyl substituent. Antibodies in serum from 7 multiple sclerosis (MS) patients and serum and cerebrospinal fluid (CSF) from 7 non-MS patients apparently reacted with the sugar moiety of LTA. In contrast, CSF antibodies from 6 of the 7 MS patients and 1 of the 7 non-MS patients had affinity for the alanine residue. This non-MS patient also had serum antibodies against the alanine residue. None of the other sera tested appeared to contain such antibodies.

Pretreatment with lipoteichoic acid sensitizes target cells to antibody-dependent cellular cytotoxicity in the presence of anti-lipoteichoic acid antibodies

This study was performed to determine whether antibody-dependent cellular cytotoxicity (ADCC) could be directed against mammalian cells sensitized with spontaneously adhering bacterial substances. 51Cr-labeled SB leukemia cells were incubated with purified S43 group A streptococcal lipoteichoic acid (LTA; 0.001 to 100 micrograms/ml). Purified leukocyte ADCC effector cells were added to the LTA-coated target cells at various effector-to-target ratios (100:1 to 12:1), followed by the addition of rabbit anti-LTA. After incubation for 4 h, target cell lysis was calculated based on the release of label into the medium. As little as 1 ng of LTA per ml was sufficient to sensitize the target cells to ADCC lysis (12%); however, concentrations above 0.1 micrograms/ml generally resulted in 60 to 80% lysis. LTA alone was not cytotoxic to these target cells. Targeting did not occur if effector cells were sensitized or if free LTA was added to the medium. Specificity was demonstrated by cold-target inhibition, which showed that anti-LTA cytotoxicity could be inhibited only by unlabeled, LTA-treated target cells but not by cold SB cells alone. The findings indicate that certain soluble bacterial components, when bound to mammalian cells in the presence of specific antibody, can target ADCC effectors to these cells. This mechanism may be an important factor in the delayed sequelae of bacterial infections.

Chemical properties and immunobiological activities of streptococcal lipoteichoic acids

Lipoteichoic acids (LTAs) were chromatographically purified from crude phenol-water extract of whole cells of some streptococcal species, which included Streptococcus pyogenes Sv, Streptococcus mutans 6715, and Streptococcus sanguis ATCC 10556. Among these, special attention was paid to S. pyogenes LTA for analyses of chemical composition and biological activities. All LTA preparations contained equimolar amounts of glycerol and phosphorus. Chemical analyses showed that S. pyogenes LTA contained glycerophosphate, alanine, glucose, and fatty acids (as palmitic acid) at molar ratio of 1 : 0.1 : 0.1 : 0.25. The crude phenol-water extract and isolated LTA from S. pyogenes Sv were found to be mitogenic for spleen cells of BALB/c and BALB/c (nu/nu) mice, but not for thymus cells of BALB/c mice. The mitogenicity of deacylated LTA (dLTA) was significantly lower than that of LTA. It was also found that various LTA preparations possessed polyclonal B cell activation ability and adjuvant activity both in vivo and in vitro, as demonstrated by using hemolytic plaque assay. LTA, but not dLTA, induced macrophage activation which resulted in tumor cytotoxicity in mice. Limulus lysate activity of S. pyogenes LTA was approximately 1,000 fold lower than that of Escherichia coli lipopolysaccharide. These results indicate that streptococcal LTA possesses various immunobiological activities that modulate lymphoreticular system in vivo and in vitro.

Activation of the alternative complement pathway by pneumococcal lipoteichoic acid

Cell wall teichoic acids of some gram-positive bacteria are potent activators of the alternative pathway of complement. It is unclear, however, whether the other form of teichoic acid, cell membrane lipoteichoic acid (LTA), can also activate the alternative pathway. In the present study, radiolabelled pneumococcal LTA was found to bind spontaneously to sheep erythrocytes in a temperature- and time-dependent fashion. In addition, the presence of pneumococcal LTA on the erythrocyte surface was verified by the fact that they could be agglutinated by a myeloma protein (TEPC-15) specific for choline, a constituent of pneumococcal LTA. Pneumococcal LTA when fixed to the surface of erythrocytes was able to activate the alternative pathway of complement in both guinea pig serum deficient in the fourth component of complement and human serum deficient in the second component of complement, resulting in lysis of the sensitized erythrocytes. The sensitizing principle of the LTA preparation was removed before erythrocyte sensitization by immunoabsorption, using the choline-specific TEPC-15 myeloma protein. These data demonstrate that purified pneumococcal LTA will bind to sheep erythrocytes and endow them with the ability to activate the alternative pathway.

Pneumococcal Forssman antigen: enrichment in mesosomal membranes and specific binding to the autolytic enzyme of Streptococcus pneumoniae

The choline-containing pneumococcal membrane teichoic acid (Forssman antigen) can be isolated with the membrane fractions of the bacteria. The small vesicle (mesosomal) fraction generated during the formation of protoplasts seems to be highly enriched in this material. Forssman antigen was identified in cell fractions on the basis of (i) radioactive choline label, (ii) autolysin-inhibitory activity, and (iii) the sedimentation profile in sucrose density gradients with and without detergent. A membrane teichoic acid could also be isolated from pneumococci grown in medium in which choline was replaced by ethanolamine as the nutritionally required amino alcohol. This material contained radioactive ethanolamine label and behaved similarly to the choline-containing membrane teichoic acid during centrifugation in detergent-containing and detergent-free density gradients. On the other hand, the material had only low autolysin-inhibitory activity. Binding of pure pneumococcal autolysin to micelles of purified Forssman antigen could be demonstrated by mixing these components in vitro and analyzing them by sucrose density gradients and by agarose chromatography. No binding could be observed between the pneumococcal enzyme and the micellar forms of either cardiolipin or polyglycerophosphate-type lipoteichoic acid isolated from Streptococcus lactis.

Interaction of bifidobacterial lipoteichoic acid with human intestinal epithelial cells

Binding of the lipoteichoic acids of Bifidobacterium bifidum to human colonic epithelial cells appeared to be specific, reversible, and cell concentration and time dependent. A single population of approximately 8.3 X 10(8) binding sites per cell was detected, with a dissociation constant of 125 microM. Ester-linked fatty acids are essential for binding.

Isolation and partial characterization of staphylococcal decomplementation antigen

A substance with potent decomplementation activity was isolated from staphylococcal culture supernatants by polyethylene glycol precipitation, DEAE-ion-exchange and Sephacryl chromatography, and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified substance exhibited all the characteristics of the decomplementation antigen (DA) previously detected in unfractionated culture supernatants. It contained glucosamine and phosphorus and was provisionally identified as extracellular, water-soluble teichoic acid of Staphylococcus aureus. DA was entirely resistant towards the action of proteases, DNase, RNase, or lysostaphin and withstood boiling for 30 min. Its electrophoretic mobility in agarose gels at pH 8.7 was approximately double that of human serum albumin. The molecule eluted in a molecular-weight region of 70,000 to 120,000 on Sephacryl S-300 and sedimented as a symmetrical 3 to 4 S moiety in sucrose density gradients. It migrated near the dye front on 12.5% sodium dodecyl sulfate-polyacrylamide gels and remained undenatured after boiling in sodium dodecyl sulfate. DA formed a symmetrical immunoprecipitate upon crossed immunoelectrophoresis against pooled human immunoglobulin G. It was identified as the major extracellular antigen present in unfractionated S. aureus culture supernatants that is precipitable by naturally occurring human immunoglobulin G antibodies. Immune complexes forming between DA and human immunoglobulin G exhibited an extraordinary capacity to activate the classical complement pathway. Micro- or nanogram amounts of purified antigen added to antibody-containing human serum effected rapid and complete consumption of C3, C4, and C5. The biochemical and biological properties of DA single out this molecule for an important role in suppressing the opsonizing activity of host complement through induction of abortive complement consumption in the fluid phase.

Antibodies to Staphylococcus aureus peptidoglycan and lipoteichoic acid in sera from blood donors and patients with staphylococcal infections

An enzyme-linked immunoassay (ELISA) was used to detect antibodies in human sera to Staphylococcus aureus peptidoglycan (PG) and lipoteichoic acid (LTA). All the sera from the blood donors contained IgG antibodies to both substances. Among the sera from 34 patients with bacteriologically verified, serious S. aureus infections, 71 per cent contained significantly elevated levels of anti-PG antibodies and 76 per cent of anti-LTA antibodies. Among the sera from 38 patients with suspected but not bacteriologically verified staphylococcal infections, 58 per cent contained significantly elevated levels of anti-PG antibodies and 74 per cent of anti-LTA antibodies. The levels of antibodies to PG correlated well with the levels of antibodies to LTA, but the latter occurred over a broader range in the patient sera. Elevated antibody values were, however, also found in some patients with serious, non-staphylococcal infections. The diagnostic value of PG and LTA antibodies has to be further investigated.

Interaction of anti-kojibiose antibody with the lipoteichoic acids from Streptococcus faecalis and Streptococcus faecium

Antisera prepared in rabbits by immunization with p-aminophenyl beta-kojibioside conjugated to bovine serum albumin (antikojibiose sera), readily agglutinated whole cells of Streptococcus faecalis or Streptococcus faecium, and showed specific reactions with the lipoteichoic acids (LTAs) of these streptococci by passive hemagglutination, microscale enzyme-linked immunosorbent assay, and crossed immunoelectrophoresis. The interaction of the antikojibiose sera with the LTAs was inhibited best by kojibiose [alpha-D-glucopyranosyl-(1----2)-D-glucose], somewhat less by the dextran from which the kojibiose was prepared, and not measurably by maltose [alpha-D-glucopyranosyl-(1----4)-D-glucose]. The sera reacted only minimally in only the most sensitive assay (microscale enzyme-linked immunosorbent assay) with LTA from group A streptococci (this LTA contains a single kojibiosyl residue as part of the glycolipid moiety of the molecule and failed to react with the Lactobacillus fermentum LTA which is substituted with alpha-D-galactopyranosyl-(1----2)-D -glucosyl units.