Nasal boost with adjuvanted heat-killed BCG or arabinomannan–protein conjugate improves primary BCG-induced protection in C57BL/6 mice

Today it is generally accepted that the Bacillus Calmette-Guerin (BCG) vaccine protects against childhood tuberculosis (TB) but this immunity wanes with age, resulting in insufficient protection against adult pulmonary TB. Hence, one possible strategy to improve the protective efficacy of the BCG vaccine would be to boost in adulthood. In this study, using the mouse model, we evaluated the ability of two new TB vaccine candidates, heat-killed BCG (H-kBCG) and arabinomannan-tetanus toxoid conjugate (AM-TT), given intransally in a novel Eurocine adjuvant, to boost a primary BCG-induced immune response and to improve protection. Young C57BL/6 mice were vaccinated with conventional BCG and, 6 months later, boosted intranasally with adjuvanted H-kBCG or AM-TT, or subcutaneously with BCG. Ten weeks after the booster, mice were challenged intravenously with M. tuberculosis (Mtb) strain H37Rv. In spleens, there was a significant reduction of cfu counts in mice boosted with either H-kBCG or AM-TT vaccines compared to the non-boosted BCG-vaccinated mice. None of the boosting regimens significantly reduced bacterial loads in lungs, compared to non-boosted BCG vaccination. However, the extent of granulomatous inflammation was significantly reduced in the lungs of mice that received two of the booster vaccines (AM-TT and conventional BCG), as compared with sham-vaccinated mice. All boosted groups, except for mice boosted with the AM-TT vaccine, responded with a proliferation of spleen T cells and gamma interferon production comparable to that induced by a single BCG vaccination.

A mycobacterial lipoarabinomannan specific monoclonal antibody and its F(ab') fragment prolong survival of mice infected with Mycobacterium tuberculosis

Lipoarabinomannan (LAM) is a major structural carbohydrate antigen of the outer surface of Mycobacterium tuberculosis. High antibody titres against LAM are often seen in active tuberculosis (TB). The role of such LAM-specific antibodies in the immune response against TB is unknown. Here we have investigated a monoclonal antibody (MoAb) SMITB14 of IgG1 subclass and its corresponding F(ab')(2) fragment directed against LAM from M. tuberculosis strain H37Rv. MoAb SMITB14 was shown by immunofluorescence to bind to whole cells of the clinical isolate M. tuberculosis strain Harlingen as well as to M. tuberculosis H37Rv. The binding of MoAb SMITB14 to LAM was inhibited by arabinomannan (AM) and oligosaccharides (5.2 kDa) derived from LAM, showing that the MoAb binds specifically to the AM carbohydrate portion of LAM. In passive protection experiments BALB/c mice were infected intravenously with M. tuberculosis Harlingen. MoAb SMITB14 was added intravenously either prior to, or together with, the bacteria. The antibody proved to be protective against the M. tuberculosis infection in terms of a dose-dependent reduction in bacterial load in spleens and lungs, reduced weight loss and, most importantly, increased long-term survival.

Immunization with heat-killed Mycobacterium bovis bacille Calmette–Guerin (BCG) in Eurocine™ L3 adjuvant protects against tuberculosis

The current live attenuated vaccine against tuberculosis, BCG, poses a risk of disseminated infections in immunocompromised subjects. Therefore, in this study we compared the protective effect of a heat-killed bacille Calmette-Guerin (H-kBCG) vaccine given in a new adjuvant (Eurocine L3) with the protection provided by the conventional live attenuated BCG vaccine in mice (C57BL/6 and BALB/c) challenged with virulent Mycobacterium tuberculosis (strain Harlingen). The H-kBCG vaccine alone, in accordance with earlier studies, did not give any or only gave slight protection compared to sham-vaccinated controls. However, the same vaccine given with Eurocine L3 adjuvant, either formulated as a suspension or as an emulsion, afforded significant levels of protection. This protection was at least as good as that of the control live attenuated BCG vaccine. The Eurocine L3 adjuvant is approved for human use as a nasal vaccine adjuvant and a successful phase I trial with nasal immunization with diphtheria vaccine has recently been performed in Sweden. Here we show that, in mice, intranasal priming with H-kBCG in Eurocine L3 adjuvant followed by intranasal booster resulted in the same level of protection as subcutaneous priming followed by intranasal booster. All H-kBCG formulations in the Eurocine L3 adjuvant elicited mycobacterial antigen-specific serum IgG and IFN gamma responses. In general, among the different vaccine formulation(s) in the Eurocine L3 adjuvant those that produced a relatively high Th2 response, as measured by IgG1/IgG2a ratio and IFN gamma production in vitro, were the most protective. In conclusion, H-kBCG in Eurocine L3 adjuvant could represent a safe and a more stable alternative to the conventional live BCG vaccine.

Diagnostic evaluation of urinary lipoarabinomannan at an Ethiopian tuberculosis centre

Direct capture enzyme-linked immunosorbent assay (ELISA) for lipoarabinomannan (LAM) was performed on urine samples from 200 tuberculosis (TB) patients and 800 non-TB patients routinely diagnosed among consecutive suspects in an Ethiopian TB centre. 50 healthy Ethiopians, 50 healthy individuals and 100 non-TB patients from Norway served as controls. Of the TB patients, 139 (69.5%) were positive for acid-fast bacilli (AFB). In the remaining cases the diagnosis was based on suggestive clinical findings. All Ethiopian non-TB patients were AFB negative and showed no clinical evidence of TB. In the Ethiopian groups, 148 (74%) of the TB patients, 105 (13.1%) of the non-TB patients and 5 (10%) of the healthy controls were positive by the LAM-ELISA. 113 (81.3%) of AFB positives and 35 (57.4%) of AFB-negative TB patients had positive LAM-ELISA. In the Norwegian groups all were LAM negative. The sensitivity and specificity of the LAM-ELISA for TB patients versus Ethiopian non-TB patients were 74% and 86.9%, respectively; the positive and negative predictive values were 58.5% and 93.0%. This study suggests that detection of LAM in the urine of TB patients may improve case finding and that diagnostic tests based on this principle may serve as valuable supplemental tools in TB control.

Rapid diagnosis of tuberculosis by detection of mycobacterial lipoarabinomannan in urine

There is an urgent need for improved tools for laboratory diagnosis of active tuberculosis (TB). Here, we describe two methods, a catch-up ELISA and a dipstick test based on the detection in urine of lipoarabinomannan (LAM). LAM is a major and specific glycolipid component of the outer mycobacterial cell wall. Preliminary experiments showed that LAM is excreted in the urine of mice injected intraperitoneally with a crude cell wall preparation of Mycobacterium tuberculosis. Both methods were highly sensitive, detecting LAM at concentrations of 1 ng/ml and 5 pg/ml, respectively. Of 15 patients with active TB, all showed intermediate to high levels of LAM in their urine (absorbance values from 0.3 to 1.2, mean 0.74). Only one sample showed an absorbance value below the chosen cut off value of 0.4. All but one of the urine samples from 26 healthy nursing workers exhibited OD value below 0.4 cut off. These methods may prove valuable for rapid and simple diagnosis of TB in particular in developing countries lacking biosafety level 3 (BSL3) facilities.

Synthesis and immunologic characterisation of Mycobacterium tuberculosis lipoarabinomannan specific oligosaccharide-protein conjugates

Lipoarabinomannan (LAM) is a major structural surface component of all mycobacteria, and has been reported to have a wide range of biological effects. Immunogenic LAM specific oligosaccharide protein conjugates were synthesized and immunologically characterized. Oligosaccharides were derived from LAM purified from Mycobacterium tuberculosis H37 Rv and covalently conjugated to tetanus toxoid and cross reactive mutant (CRM197) diphtheria toxoid. Both types of LAM oligosaccharide protein conjugates proved to be highly immunogenic, inducing a boosterable T helper cell dependent IgG response. These conjugates are currently evaluated as components in a subcellular experimental TB vaccine.

A new rapid and simple method for large-scale purification of mycobacterial lipoarabinomannan

Lipoarabinomannan (LAM) is a major and structurally important outer cell wall component of all mycobacteria. LAM is also generally regarded as an important immunomodulating substance affecting several immunologic networks and hence important in the pathogenesis of mycobacterial infections. We here describe a new method for large-scale purification of mycobacterial LAM. A crude cell wall preparation was prepared from batch-grown Mycobacterium tuberculosis H37Rv. From this cell wall preparation LAM was purified by sequential extractions and chromatographic steps. From 20 g dry weight cell wall preparation 313 mg of highly purified (> 98%) LAM was obtained in only 3 days. The LAM content of the final purification step was quantified by ELISA using reference LAM as standard. The identity and purity of the LAM preparation was further confirmed by comparison with reference LAM preparation from M. tuberculosis strain Erdman in polyacrylamide gel electrophoresis and Western blots, using reference anti-LAM monoclonals CS-35 and CS-40.

Involvement of antilipoarabinomannan antibodies in classical complement activation in tuberculosis

We examined alternative and classical complement activation induced by whole bacilli of Mycobacterium bovis BCG and Mycobacterium tuberculosis products. After exposure to BCG, there were higher levels of the terminal complement complex in sera from Indian tuberculosis patients than in sera from healthy controls. The addition of BCG with or without EGTA to these sera indicated that approximately 70 to 85% of the total levels of the terminal complement complex was formed by classical activation. Sera from Indian tuberculosis patients contained more antibody to lipoarabinomannan (LAM) than sera from healthy Indians. Levels of anti-LAM immunoglobulin G2 (IgG2), but not anti-LAM IgM, correlated positively with classical activation induced by BCG in the sera. By flow cytometry, deposition of C3 and terminal complement complex on bacilli incubated with normal human serum was demonstrated. The anticomplement staining was significantly reduced in the presence of EGTA and EDTA. Flow cytometry also revealed the binding of complement to BCG incubated with rabbit anti-LAM and then with factor B-depleted serum. This indicates that classical activation plays a major role in complement activation induced by mycobacteria and that anti-LAM IgG on the bacilli can mediate this response. Classical complement activation may be important for the extent of phagocytosis of M. tuberculosis by mononuclear phagocytes, which may influence the course after infection.

Plant mitochondrial F0F1 ATP synthase. Identification of the individual subunits and properties of the purified spinach leaf mitochondrial ATP synthase

Spinach leaf mitochondrial F0F1 ATPase has been purified and is shown to consist of twelve polypeptides. Five of the polypeptides constitute the F1 part of the enzyme. The remaining polypeptides, with molecular masses of 28 kDa, 23 kDa, 18.5 kDa, 15 kDa, 10.5 kDa, 9.5 kDa and 8.5 kDa, belong to the F0 part of the enzyme. This is the first report concerning identification of the subunits of the plant mitochondrial F0. The identification of the components is achieved on the basis of the N-terminal amino acid sequence analysis and Western blot technique using monospecific antibodies against proteins characterized in other sources. The 28-kDa protein crossreacts with antibodies against the subunit of bovine heart ATPase with N-terminal Pro-Val-Pro- which corresponds to subunit F0b of Escherichia coli F0F1. Sequence analysis of the N-terminal 32 amino acids of the 23-kDa protein reveals that this protein is similar to mammalian oligomycin-sensitivity-conferring protein and corresponds to the F1 delta subunit of the chloroplast and E. coli ATPases. The 18.5-kDa protein crossreacts with antibodies against subunit 6 of the beef heart F0 and its N-terminal sequence of 14 amino acids shows a high degree of sequence similarity to the conserved regions at N-terminus of the ATPase subunits 6 from different sources. ATPase subunit 6 corresponds to subunit F0a of the E. coli enzyme. The 15-kDa protein and the 10.5-kDa protein crossreact with antibodies against F6 and the endogenous ATPase inhibitor protein of beef heart F0F1-ATPase, respectively. The 9.5-kDa protein is an N,N'-dicyclohexylcarbodiimide-binding protein corresponding to subunit F0c of the E. coli enzyme. The 8.5-kDa protein is of unknown identity. The isolated spinach mitochondrial F0F1 ATPase catalyzes oligomycin-sensitive ATPase activity of 3.5 mumol.mg-1.min-1. The enzyme catalyzes also hydrolysis of GTP (7.5 mumol.mg-1.min-1) and ITP (4.4 mumol.mg-1.min-1). Hydrolysis of ATP was stimulated fivefold in the presence of amphiphilic detergents, however the hydrolysis of other nucleotides could not be stimulated by these agents. These results show that the plant mitochondrial F0F1 ATPase complex differs in composition from the other mitochondrial, chloroplast and bacterial ATPases. The enzyme is, however, more closely related to the yeast mitochondrial ATPase and to the animal mitochondrial ATPase than to the chloroplast enzyme. The plant mitochondrial enzyme, however, exhibits catalytic properties which are characteristic for the chloroplast enzyme.

F0F1-ATPase of plant mitochondria: isolation and polypeptide composition

A simple and high yield purification procedure for the isolation of F0F1-ATPase from spinach leaf mitochondria has been developed. This is the first report concerning purification and composition of the plant mitochondrial F0F1-ATPase. The enzyme is selectively extracted from inner membrane vesicles with the zwitterionic detergent, 3-[(3-cholamidopropyl) dimethyl ammonio]-1- propane sulfonate (CHAPS). The purified enzyme exhibits a high oligomycin-sensitive ATPase activity (3,6 mumol.min-1.mg-1). SDS-PAGE of the purified F0F1-ATPase complex reveals protein bands of molecular masses of 54 kDa (F1 alpha,beta), 33 kDa (F1 gamma), 28 kDa, 23 kDa, 21 kDa (F1 delta), 18.5 kDa, 15 kDa, 10.5 kDa, 9.5 kDa (F1 epsilon) and 8.5 kDa. All polypeptides migrate as one complex in a polyacrylamide gradient gel under non-denaturing conditions in the presence of 0.1% Triton X-100. Five polypeptides could be identified as subunits of F1. Polypeptides of molecular masses 28 kDa, 23 kDa, 18.5 kDa, 15 kDa, 10.5 kDa, 9.5 kDa and 8.5 kDa constitute the F0 part of the complex. Our results show that polypeptide composition of the plant mitochondrial F0 differs from other eukaryotic F0 of yeast, mammals and chloroplasts.

Evidence for an endogenous ATPase inhibitor protein in plant mitochondria. Purification and characterization

An endogenous ATPase inhibitor protein has been identified and isolated for the first time from plant mitochondria. The inhibitor protein was isolated from potato (Solanum tuberosum) tuber mitochondria and purified to homogeneity. The isolated inhibitor is a heat-stable, trypsin-sensitive, basic protein, with a molecular mass approximately 8.3 kDa. Amino acid analysis reveals a high content of glutamic acid, lysine and arginine and the absence of proline; threonine and leucine. The interaction of the inhibitor with F1-ATPase requires the presence of Mg2(+)-ATP in the incubation medium. The ATPase activity of isolated F1 is inhibited to 50% in the presence of 14 micrograms inhibitor/mg F1. A stoichiometry of 1.3 mol inhibitor/mol F1 for complete inhibition can be calculated from this value. The potato ATPase inhibitor is also a potent inhibitor of the ATPase activity of the isolated yeast F1. The inhibitor resembles the ATPase inhibitors of yeast and mammalian mitochondria, and does not seem to be related to the inhibitory peptide, epsilon subunit, of chloroplast ATPase.

Quantitative determination of arsenocholine and acetylarsenocholine in aquatic organisms using pyrolysis and gas chromatography/mass spectrometry

A method for qualitative and quantitative analysis of trace amounts of quaternary organoarsenicals such as arsenocholine and acetylarsenocholine has been developed. The method is based on pyrolysis, gas chromatography/mass spectrometry and use of deuterium-labelled internal standards. Arsenocholine and acetylarsenocholine have been estimated in fish from arsenic-polluted brackish water and compared with the same species of fish from unpolluted water. The investigation also includes some fish and crustacea from marine water. The presence of arsenocholine and acetylarsenocholine in different aquatic organisms indicate the existence of a general metabolic pathway for these compounds in aquatic ecosystems.

Cross-reconstitution of isolated F1-ATPase from potato tuber mitochondria with F1-depleted beef heart and yeast submitochondrial particles

Cross-reconstitution of isolated potato mitochondrial F1-ATPase with F1-depleted beef heart and yeast submitochondrial particles is reported. Potato F1 binds to the heterologous membrane and confers oligomycin sensitivity on the ATPase activity of the reconstituted system. Binding of F1 is promoted by the presence of Mg2+ with the maximal stimulatory effect at 20 mM. Mg2+ increase the sensitivity to oligomycin of the reconstituted system consisting of potato F1 and yeast membranes, however, they do not influence oligomycin sensitivity of potato F1 and beef heart membranes.