Design and Optimization of a Temperature-Stable Dry Powder BCG Vaccine.

PURPOSE: Loss of vaccine potency due to extreme temperature exposure during storage and transport remains a significant obstacle to the success of many vaccines, including the Bacille Calmette-Guérin (BCG) vaccine, the only vaccine available against Mycobacterium tuberculosis. BCG is a live, attenuated vaccine requiring refrigerated storage for viability. In this study, we formulated a temperature-stable BCG dry powder using the spray drying technique. METHODS: We employed a factorial design to optimize our formulation of stabilizing excipients that included L-leucine, bovine serum albumin, polyvinylpyrrolidone, mannitol, and trehalose. Powders were characterized for their particle size, yield, water retention and uptake, glass transition temperature, and aerosol performance. Three optimal powder carrier mixtures were selected from the factorial design for BCG incorporation based on their stability-promoting and powder flow characteristics. Vaccine powders were also assessed for BCG viability and in vivo immunogenicity after long-term storage. RESULTS: Live BCG was successfully spray-dried using the optimized carriers. Dry powder BCG showed no loss in viability (25°C, up to 60% relative humidity; RH) and ~2-log loss in viability (40°C, 75% RH) after one year of storage. The aerodynamic size of the powders was in the respirable range. Further, when healthy mice were immunized intradermally with reconstituted BCG powders (storage for 2 years), the vaccine retained its immunogenicity. CONCLUSION: We developed a spray-dried BCG vaccine that was viable and antigenic after long-term storage. To our knowledge, this is a first study to show room temperature stability of live BCG vaccine without any loss in viability for 12 months.

In Vitro Study of the Modulatory Effects of Levofloxacin and BCG on Secretion of Proinflammatory Cytokines in Infiltrative Pulmonary Tuberculosis.

The effects levofloxacin (fluoroquinolone) and vaccinal BCG strain on cytokine production by blood mononuclear leukocytes was studied in patients with infiltrative pulmonary tuberculosis. Combined treatment with levofloxacin and vaccinal BCG strain suppressed the production of TNFα in drug-resistant pulmonary tuberculosis and production of IL-12 and IFNγ in drug-sensitive tuberculosis.

Application of BCG-CWS as a Systemic Adjuvant by Using Nanoparticulation Technology.

The intravesical instillation of live Bacillus Calmette-Guerin (BCG) for treating bladder cancer is a powerful cancer immunotherapy. The BCG cell wall skeleton (BCG-CWS) is the main component of the adjuvant, leading to the induction of antitumor immunity. However, the use of live BCG and BCG-CWS is currently limited to local administration because of the infectiousness of live BCG and the insolubility of BCG-CWS. We previously developed a water-dispersible nanoparticle (NP) formulation of BCG-CWS (CWS-NP), which could be used to apply BCG components for use as a systemically injected adjuvant for the treatment of cancers other than bladder cancer. In the present study, we examined the possible use of CWS-NP for cancer immunotherapy, when intravenously administered. The CWS-NP was a highly uniform dispersion and showed no aggregation in serum. The intravenously injected CWS-NP accumulated in the spleen and was efficiently taken up by dendritic cells, leading to their maturation. The coadministration of CWS-NP and ovalbumin (OVA) loaded NP resulted in the generation of OVA-specific cytotoxic T cells and inhibited the growth of E.G7-OVA tumors. These results represent the first findings related to the use of systemically injected CWS-NP as an adjuvant for cancer immunotherapy.

Dielectrophoretic characterization of antibiotic-treated Mycobacterium tuberculosis complex cells.

Multi-drug resistant tuberculosis (MDR-TB) has become a serious concern for proper treatment of patients. As a phenotypic method, dielectrophoresis can be useful but is yet to be attempted to evaluate Mycobacterium tuberculosis complex cells. This paper investigates the dielectrophoretic behavior of Mycobacterium bovis (Bacillus Calmette-Guérin, BCG) cells that are treated with heat or antibiotics rifampin (RIF) or isoniazid (INH). The experimental parameters are designed on the basis of our sensitivity analysis. The medium conductivity (σ(m)) and the frequency (f) for a crossover frequency (f(xo1)) test are decided to detect the change of σ(m)-f(xo1) in conjunction with the drug mechanism. Statistical modeling is conducted to estimate the distributions of viable and nonviable cells from the discrete measurement of f (xo1). Finally, the parameters of the electrophysiology of BCG cells, C(envelope) and σ(cyto), are extracted through a sampling algorithm. This is the first evaluation of the dielectrophoresis (DEP) approach as a means to assess the effects of antimicrobial drugs on M. tuberculosis complex cells.

Intratumoral injection of BCG-CWS-pretreated dendritic cells following tumor cryoablation.

Intratumoral administration of dendritic cells (DC) following cryoablation of tumor is one of the personalized cancer immunotherapies which is able to induce immune responses to multiple endogenous tumor antigens, including shared and unique antigens. Here we describe protocols of cryoablation of tumors, generation of cultured DC, pretreatment of DC with a Toll-like receptor (TLR)-stimulating purified component of Bacillus Calmette-Guerin cell wall fraction (BCG-CWS) and highly immunogenic keyhole limpet hemocyanin (KLH) antigen, and combined use of tumor cryoablation and intratumoral administration of BCG-CWS-pretreated DC in both a murine model and cancer patients.

Adaptation of mycobacteria to growth conditions: a theoretical analysis of changes in gene expression revealed by microarrays.

BACKGROUND: Microarray analysis is a powerful technique for investigating changes in gene expression. Currently, results (r-values) are interpreted empirically as either unchanged or up- or down-regulated. We now present a mathematical framework, which relates r-values to the macromolecular properties of population-average cells. The theory is illustrated by the analysis of published data for two species; namely, Mycobacterium bovis BCG Pasteur and Mycobacterium smegmatis mc(2) 155. Each species was grown in a chemostat at two different growth rates. Application of the theory reveals the growth rate dependent changes in the mycobacterial proteomes. PRINCIPAL FINDINGS: The r-value r (i) of any ORF (ORF(i)) encoding protein p (i) was shown to be equal to the ratio of the concentrations of p (i) and so directly proportional to the ratio of the numbers of copies of p (i) per population-average cells of the two cultures. The proportionality constant can be obtained from the ratios DNA: RNA: protein. Several subgroups of ORFs were identified because they shared a particular r-value. Histograms of the number of ORFs versus the expression ratio were simulated by combining the particular r-values of several subgroups of ORFs. The largest subgroup was ORF(j) (r (j)  = 1.00± SD) which was estimated to comprise respectively 59% and 49% of ORFs of M. bovis BCG Pasteur and M. smegmatis mc(2) 155. The standard deviations reflect the properties of the cDNA preparations investigated. SIGNIFICANCE: The analysis provided a quantitative view of growth rate dependent changes in the proteomes of the mycobacteria studied. The majority of the ORFs were found to be constitutively expressed. In contrast, the protein compositions of the outer permeability barriers and cytoplasmic membranes were found to be dependent on growth rate; thus illustrating the response of bacteria to their environment. The theoretical approach applies to any cultivatable bacterium under a wide range of growth conditions.

Overexpression of the KdpF membrane peptide in Mycobacterium bovis BCG results in reduced intramacrophage growth and altered cording morphology.

Membrane peptides appear as an emerging class of regulatory molecules in bacteria, which can interact with membrane proteins, such as sensor kinases. To date, regulatory membrane peptides have been completely overlooked in mycobacteria. The 30 amino-acid-long KdpF peptide, which is co-transcribed with kdpABC genes and regulated by the KdpDE two-component system, is supposed to stabilize the KdpABC potassium transporter complex but may also exhibit unsuspected regulatory function(s) towards the KdpD sensor kinase. Herein, we showed by quantitative RT-PCR that the Mycobacterium bovis BCG kdpAB and kdpDE genes clusters are differentially induced in potassium-deprived broth medium or within infected macrophages. We have overexpressed the kdpF gene in M. bovis BCG to investigate its possible regulatory role and effect on mycobacterial virulence. Our results indicate that KdpF does not play a critical regulatory role on kdp genes expression despite the fact that KdpF interacts with the KdpD sensor kinase in a bacterial two-hybrid assay. However, overexpression of kdpF results in a significant reduction of M. bovis BCG growth in both murine and human primary macrophages, and is associated with a strong alteration of colonial morphology and impaired cording formation. To identify novel KdpF interactants, a mycobacterial library was screened using KdpF as bait in the bacterial two-hybrid system. This allowed us to identify members of the MmpL family of membrane proteins, known to participate in the biosynthesis/transport of various cell wall lipids, thus highlighting a possible link between KdpF and cell wall lipid metabolism. Taken together, these data suggest that KdpF overexpression reduces intramacrophage growth which may result from alteration of the mycobacterial cell wall.

Detection of pathogenic mycobacteria based on functionalized quantum dots coupled with immunomagnetic separation.

Mycobacteria have always proven difficult to identify due to their low growth rate and fastidious nature. Therefore molecular biology and more recently nanotechnology, have been exploited from early on for the detection of these pathogens. Here we present the first stage of development of an assay incorporating cadmium selenide quantum dots (QDs) for the detection of mycobacterial surface antigens. The principle of the assay is the separation of bacterial cells using magnetic beads coupled with genus-specific polyclonal antibodies and monoclonal antibodies for heparin-binding hemagglutinin. These complexes are then tagged with anti-mouse biotinylated antibody and finally streptavidin-conjugated QDs which leads to the detection of a fluorescent signal. For the evaluation of performance, the method under study was applied on Mycobacterium bovis BCG and Mycobacterium tuberculosis (positive controls), as well as E. coli and Salmonella spp. that constituted the negative controls. The direct observation of the latter category of samples did not reveal fluorescence as opposed to the mycobacteria mentioned above. The minimum detection limit of the assay was defined to 10(4) bacteria/ml, which could be further decreased by a 1 log when fluorescence was measured with a spectrofluorometer. The method described here can be easily adjusted for any other protein target of either the pathogen or the host, and once fully developed it will be directly applicable on clinical samples.

Guía clínica del carcinoma urotelial no músculo invasivo de la Asociación Europea de Urología / EAU Guidelines on Non-Muscle-Carcinoma of the Bladder

Contexto y objetivos: Presentar una puesta al día de la versión del 2008 de la guía clínica de la Asociación Europea de Urología (EUA) sobre el cáncer vesical no músculo invasivo. Evidencia adquirida: Se ha realizado una revisión sistemática de la literatura reciente acerca del diagnóstico y tratamiento del cáncer vesical no músculo invasivo. Las guías clínicas fueron puestas al día y se asignó un nivel de evidencia así como un grado de recomendación. Evidencia sintetizada: El diagnóstico del cáncer vesical depende de la cistoscopia y de los hallazgos histológicos del tejido resecado. Una correcta y completa resección transuretral (RTU) es esencial en el pronóstico del paciente. Cuando la primera resección es incompleta o cuando se diagnostica un tumor de alto grado o T1, se debe realizar una segunda resección a las 2-6 semanas. El riesgo a corto y a largo plazo tanto de la recidiva como de la progresión serán calculados de manera individual a través de tablas de riesgo y sistemas de puntuación. La estratificación de los pacientes en grupos de bajo, intermedio y alto riesgo (separando la recidiva y la progresión), supone la piedra angular para indicar un tratamiento adyuvante. Es altamente recomendable en pacientes de bajo riesgo de recidiva y progresión, una instilación inmediata de quimioterapia. En aquellos que tienen riesgo intermedio o alto de recidiva y un riesgo intermedio de progresión, se debe administrar una instilación inmediata de quimioterapia seguido de instilaciones periódicas de quimioterapia o un mínimo de un año con Bacilo de Calmette-Guerin (BCG). En pacientes con alto riesgo de progresión tumoral, tras una administración inmediata de quimioterapia, está indicado BCG intravesical como mínimo durante un año. Una cistectomía inmediata debería ser ofrecida a pacientes de altísimo riesgo y en pacientes en los que ha fallado la BCG. La versión extensa de las guías clínicas está disponible en www.uroweb.org. Conclusiones: Esta guía clínica de la EUA presenta una información actualizada sobre el diagnóstico y tratamiento del cáncer vesical además de ofrecer recientes hallazgos con el fin de aplicarlos a la práctica clínica diaria (AU)

Context and objective: To present the updated version of 2008 European Association of Urology (EAU) guidelines on non-muscle-invasive bladder cancer. Evidence acquisition: A systematic review of the recent literature on the diagnosis and treatment of non-muscle-invasive bladder cancer was performed. The guidelines were updated and the level of evidence and grade of recommendation were assigned. Evidence synthesis: The diagnosis of bladder cancer depends on cystoscopy and histologic evaluation of the resected tissue. A complete and correct transurethral resection (TUR) is essential for the prognosis of the patient. When the initial resection is incomplete or when a high-grade or T1 tumour is detected, a second TUR within 2–6 wk should be performed. The short- and long-term risks of both recurrence and progression may be estimated for individual patients using the scoring system and risk tables. The stratification of patients to low, intermediate, and high-risk groups—separately for recurrence and progression—represents the cornerstone for indication of adjuvant treatment. In patients at low risk of tumour recurrence and progression, one immediate instillation of chemotherapy is strongly recommended. In those at an intermediate or high risk of recurrence and an intermediate risk of progression, one immediate instillation of chemotherapy should be followed by further instillations of chemotherapy or a minimum of 1 yr of bacillus Calmette-Guerin (BCG). In patients at high risk of tumour progression, after an immediate instillation of chemotherapy, intravesical BCG for at least 1 yr is indicated. Immediate cystectomy may be offered to the highest risk patients and in patients with BCG failure. The long version of the guidelines is available on www.uroweb.org. Conclusions: These EAU guidelines present the updated information about the diagnosis and treatment of non-muscle-invasive bladder cancer and offer the recent findings for the routine clinical application (AU)

Chemical force microscopy of single live cells.

Traditionally, cell surface properties have been difficult to study at the subcellular level, especially on hydrated, live cells. Here, we demonstrate the ability of chemical force microscopy to map the hydrophobicity of single live cells with nanoscale resolution. After validating the technique on reference surfaces with known chemistry, we probe the local hydrophobic character of two medically important microorganisms, Aspergillus fumigatus and Mycobacterium bovis, in relation with function. Applicable to a wide variety of cells, the chemically sensitive imaging method presented here provides new opportunities for studying the nanoscale surface properties of live cells and for understanding their roles in mediating cellular events.

[BCG cell wall proteins enhance clearance of Pseudomonas aeruginosa in rat lungs].

OBJECTIVE: To test the function of BCG cell wall proteins in enhancing the clearance of Pseudomonas aeruginosa in rat lungs. METHODS: The BCG cells were broken by supersonic technique. The cell wall proteins were isolated by discontinues sucrose density-gradient centrifugation, and fractionated by Sephadex G-150 chromatography. The relative molecular mass of the isolated proteins was analyzed by SDS-PAGE. The hBD-1 gene mRNA expression in the SPC-A-1 cells was identified by Northern blot and RT-PCR. The cell wall component was injected intraperitoneally to the rats. Forty eight hours later, 5 X 10(6) CFU of P. aeruginosa ATCC27853 or Staphylococcus aureus ATCC25923 were inoculated via trachea. The bacteria colony in the supernatant of the homogenated lungs of the rats was counted 24 hours after the inoculation. RESULTS: Two protein components of BCG cell wall were fractionated. The relative molecular mass of component 2 was in the range of 18 X 10(3) -30 X 10(3). The hBD-1 mRNA expression detected by Northern blot was markedly enhanced by the stimulation of heat-inactivated BCG whole cells. The BCG-induced hBD-1 mRNA expression in the SPC-A-1 cells detected by RT-PCR was mainly contributed by fraction 2 of the BCG cell wall proteins. The bacteria decreased significantly in the lungs of the rats with the injection of BCG component 2 (n=8, P<0. 01). CONCLUSION: The fraction (relative molecular mass is 18 X 10(3) -30 X 10(3)) of BCG cell wall proteins improve the defense of rat lungs against P. aeruginosa infection.

An improved strategy for selective and efficient enrichment of integral plasma membrane proteins of mycobacteria.

Mycobacterial plasma membrane proteins play essential roles in many cellular processes, yet their comprehensive proteomic profiling remains challenging. This is mainly due to obstacles related to their extraction and solubilization. To tackle this problem, we have developed a novel procedure to selectively enrich mycobacterial plasma membrane proteins based on alkaline sodium carbonate washing of crude membranes followed by Triton X-114 phase partitioning. The present study assesses the efficiency of this method by proteome analysis of plasma membrane proteins from Mycobacterium bovis BCG. Extracted proteins were separated in parallel by 1-D SDS-PAGE and 2-DE and then analyzed by LC-MS/MS and MALDI-MS/MS. Our study revealed 125 proteins, of which 54 contained 1-14 predicted transmembrane domains (TMD) including nine novel proteins. The 1-D SDS-PAGE-based proteome analysis identified 81 proteins, of which 49 (60.5%) harbored TMD. This approach also revealed many hydrophobic membrane-associated/periplasmic proteins lacking TMD, but only few soluble proteins. The identified proteins were characterized with regard to biological functions and physicochemical properties providing further evidence for the high efficiency of the prefractionation method described herein.

Unusual features of the cell cycle in mycobacteria: polar-restricted growth and the snapping-model of cell division.

Cell division patterns in mycobacteria have been examined in order to further our understanding of how these important organisms grow in the apparent absence of key systems required for the growth of rod-shaped bacteria. Analysis of the distribution of cell lengths in the population during different phases of growth showed that the modal cell length decreases during later phases of growth, declining from 3.5 to 2.5 microm for Mycobacterium bovis BCG cells sampled in log phase and stationary phase, respectively. The population also became more homogeneous, as indicated by the proportion of cells in the most common class increasing from 15% to 28%. Similar patterns were observed for Mycobacterium smegmatis and Mycobacterium tuberculosis. Consistent with other actinomycetes, and in contrast to most rod-shaped bacteria, the deposition of newly synthesised peptidoglycan in mycobacteria is restricted to the poles of the cell, as evidenced by staining with fluorescently labelled vancomycin. A "V-form" of bacteria was observed in cultures at all stages of growth, but the proportion decreased in older cultures. The V-shape appears to be a result of the uneven splitting of the exterior cell envelope at the new septum; this exposes the new peptidoglycan which is illustrated by spots of fluorescent vancomycin staining associated with the exterior side of the "V", and supports the 'snapping division model'. The restriction of growth to the poles of the cell differs from the pattern observed in other rod-shaped bacteria, in which the cell poles are inert and lateral growth occurs by deposition of peptidoglycan along the body of the cylinder. The mechanisms that maintain the shape of mycobacteria and that identify the mid-point for cell division remain to be determined.

[The effects of rBCG expressing Der p2 in the form of lipoprotein on murine immune response].

AIM: To investigate the effects of rBCG vaccination containing foreign antigen Der p2 in the form of lipoprotein on murine immune response. METHODS: 6 to 8 weeks old and newborn BALB/c mice were vaccined intraperitoneally with 10(6) CFU rBCG or BCG. At the same time, the control group was injected with saline. Six weeks later, all animals were injected with Der p2 (20 microg). After two weeks later, the concentrations of IL-4 and IFN-gamma in the serum and splenocyte culture supernatant (STLCS) were determined by ELISA, and Th subgroups were determined by double fluorescent staining and flow cytometry. RESULTS: After vaccination, the serum and STLCS from both rBCG-immunized and BCG-immunized group of adult and newborn BALB/c mice had significantly higher level of IFN-gamma and lower level of IL-4 than those from control groups. Besides, there was the larger percentage of CD4 (+) IFN-gamma (+) cells in spleen from rBCG-vaccined and BCG-vaccined mice than that from control group. However, the percentage of CD4 (+) IL-4 (+) cells in spleen cells from rBCG-vaccined and BCG-vaccined group was lower than that from control group. Moreover, the level of IFN-gamma in STLCS from rBCG-immunized was significantly higher, compared with that from BCG-immunized mice. At the same time, the percentage of CD4 (+) IFN-gamma (+) cells in spleen from rBCG-vaccined mice was larger than that from BCG-vaccined group. CONCLUSION: Both rBCG and BCG could stimulate Th1 predominant immune response, when injected intraperitoneally into adult or newborn BALB/c mice, The Der p2 expressed on the cell wall of BCG can work as the component of BCG and be recognized by the immune system of mice, therefore stimulates Der p2-specific Th1 predominant immune response. These data indicate that recombinant BCG-expressing antigens can be used as the antigen-specific vaccines against allergic diseases by regulating the balance of Th1/Th2.

Generation and characterization of multicellular heterospheroids formed by human peripheral blood mononuclear cells.

A three-dimensional culture system for primary human mononuclear cells was developed, which reproducibly resulted in the formation of multicellular heterospheroids. Immunohistological characterization demonstrated not only the three-dimensional tissue-like aggregation of primary monocytes, B cells and T cells, but also the presence of macrophages and proliferating cells, indicating that a differentiation of monocytes to macrophages and an activation of cells were induced. Because of the phenotypical resemblance to granulomas the influence of an in vitro infection with mycobacteria on spheroid formation and morphology was analyzed. In comparison to control incubations, the formation of multinucleated giant cells and necrotic areas containing large numbers of mycobacteria could be observed, which resembled histological hallmarks of in situ tuberculoid granulomas. These characteristics have not been described for in vitro models of granuloma formation before and thus this new culture technique may prove to be a useful tool for analyzing aspects relevant to immunopathological processes in chronically inflamed tissues.

Cultivation of Mycobacterium bovis BCG in bioreactors.

The Mycobacterium bovis BCG vaccine for commercial use is classically produced as surface pellicles by culture on synthetic medium. Under these conditions, reproducibility of the cultures and quality assessment are hampered by slow growth of the bacilli, the formation of bacterial aggregates and a high proportion of dead bacilli after processing and final formulation of the vaccine. Here, we established dispersed cultures of M. bovis BCG in synthetic media in small-scale bioreactors. These cultures allow recording and adjusting of culture parameters and give rise to single bacilli with a high degree of live bacteria. In the murine model, bioreactor-grown M. bovis BCG exhibited slightly stronger replication and persistence than the vaccine produced under the classical conditions. The protective efficacy against challenge with M. tuberculosis was identical for both vaccine preparations.

Azole-antifungal binding to a novel cytochrome P450 from Mycobacterium tuberculosis: implications for treatment of tuberculosis.

Although antibiotics against Mycobacterium tuberculosis have decreased the incidence of tuberculosis infections significantly, the emergence of drug-resistant strains of this deadly pathogen renders current treatments ineffective. Therefore, it is imperative to identify biochemical pathways in M. tuberculosis that can serve as targets for new anti-mycobacterial drugs. We recently cloned, expressed, and purified MT CYP51, a soluble protein from M. tuberculosis that is similar in sequence to CYP51 (lanosterol-14alpha-demethylase) isozymes, pharmacological targets for several anti-mycotic compounds. Its striking amino acid sequence similarity to that of mammalian and fungal CYP51s led to the hypothesis that MT CYP51 plays an important role in mycobacterial biology that can be targeted for drug action. In this manuscript, we established through spectral analysis that several azole antifungals bind MT CYP51 with high affinity. The effects of several azole compounds on the growth of M. bovis and M. smegmatis, two mycobacterial species that closely resemble M. tuberculosis were examined. We established a correlation between the affinity of azole compounds to MT CYP51 and their ability to impair the growth of M. bovis and M. smegmatis. These results suggest that the metabolic functions of MT CYP51 may be comparable to those of CYP51 in yeast and fungi and may lead to the development of a new generation of anti-mycobacterial agents.

Opposite effects of M. leprae or M. bovis BCG delipidation on cellular accumulation into mouse pleural cavity. Distinct accomplishment of mycobacterial lipids in vivo.

OBJECTIVES AND DESIGN: The effect of mycobacterial lipids on the onset of the early acute inflammatory response in BALB/c mice pleurisy was investigated. MATERIALS AND METHODS: Intact Mycobacterium leprae and Mycobacterium bovis BCG (BCG), their lipids, and delipidated mycobacteria were used to evaluate total leukocytes and cell types migrated to the pleural cavity (8 animals/experimental group). RESULTS: BCG Moreau (x10(-6)/cavity), delipidated BCG and its lipids gradually recruited cells leading to arrival, respectively, of neutrophils (7.8+/-1.9, 4.7+/-0.9, 1.8+/-0.25) followed by mononuclear cells (4.8+/-0.8, 3.7+/-0.7, 2.45+/-0.22) and eosinophils (0.39+/-0.08, 0.32+/-0.11, 0.41+/-0.65). BCG delipidation decreased the number of migrated total leukocytes (ANOVA, and Newman-Keuls-Student-test), whereas M. leprae delipidation accumulated neutrophils (0.85+/-0.01) and eosinophils (1.65+/-0.18). CONCLUSIONS: Intact M. leprae and its lipids did not incite any cell recruitment. Apolar external cell wall lipids from M. leprae and BCG induce different cellular responses. They seem to have a crucial importance at the first contact of mycobacteria with the host cell, modulating the influx of neutrophils/macrophages in the early (4/24 h) onset of the inflammatory reaction.

Immunogenicity and efficacy of a tuberculosis DNA vaccine encoding the components of the secreted antigen 85 complex.

BALB/c and C57BL/6 mice were injected intramuscularly with plasmid DNA encoding the three components of the immunodominant 30-32 kDa antigen 85 complex (Ag85A, Ag85B, and Ag85C) from Mycobacterium tuberculosis culture filtrate, in order to investigate the utility of nucleic acid vaccination for induction of immune responses against mycobacterial antigens. Ag85A and Ag85B encoding plasmids induced a robust Th1-like response towards native Ag85, characterized by elevated levels of interleukin (IL)-2, interferon-gamma, and TNF-alpha. Levels of IL-4, IL-6, and IL-10 were low or undetectable. Plasmid encoding Ag85C was not effective. Cytotoxic T cell activity was also generated in in vitro restimulated splenocyte cultures from Ag85A and Ag85B DNA vaccinated mice. Finally, Ag85A and Ag85B DNA vaccination conferred significant protection against mycobacterial replication in lungs from B6 mice, subsequently challenged. Therefore, this technique may be useful for the definition of protective antigens of M. tuberculosis and the development of a more effective tuberculosis vaccine.