Tuberculosis is the most widespread and lethal infectious disease affecting humans. Immunization of mice with plasmid DNA constructs encoding one of the secreted components of Mycobacterium tuberculosis, antigen 85 (Ag85), induced substantial humoral and cell-mediated immune responses and conferred significant protection against challenge with live M. tuberculosis and M. bovis bacille Calmette-Guérin (BCG). These results indicate that immunization with DNA encoding a mycobacterial antigen provides an efficient and simple method for generating protective immunity and that this technique may be useful for defining the protective antigens of M. tuberculosis, leading to the development of a more effective vaccine.

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TH1 cytokine secretion was examined in response to synthetic peptides of the 85A component of the major secreted, fibronectin-binding antigen 85 complex from Mycobacterium tuberculosis in seven different mouse strains infected with live M. bovis BCG. Twenty-eight overlapping 20-mer peptides covering the complete mature 295-amino-acid (AA) protein were synthesized. Significant interleukin-2 (IL-2) and gamma interferon (IFN-gamma) secretion could be measured following in vitro stimulation of spleen cells with these peptides. H-2d haplotype mice reacted preferentially against the amino-terminal half of the protein, i.e., against peptide 5 (AA 41 to 60) and especially against peptide 11 (AA 101 to 120), which contained an I-Ed binding motif. H-2b haplotype mice, on the other hand, reacted against peptides from both amino- and carboxy-terminal halves of the protein, peptide 25 (AA 241 to 260) being the most potent stimulator of IL-2 and IFN-gamma production. (BALB/c x C57BL/6)F1 animals with the H-2d/b haplotype weakly recognized peptides specific for both parental lines. Finally, CBA/J (H-2k) and major histocompatibility complex class II mutant B6.C.bm12 mice, carrying a mutant I-A beta bm12 allele on an H-2b background, reacted only very weakly to the 85A peptides. Reactive T cells isolated from lungs of BCG-infected H-2b haplotype mice recognized the same epitopes as spleen cells, especially peptide 25. These data confirm previous findings regarding the powerful IL-2 and IFN-gamma-inducing properties of antigen 85 during infection with live M. bovis BCG.

Objective Salmonella spp. are one of the leading foodborne pathogens worldwide naturally found in the intestines of many animals. People that are in direct contact with the infected animals or their cages may become ill. The aim of this study was to determine the prevalence, antibiogram and virulence genes associated with Salmonella serovars from fecal samples of animals intended for consumption in Southern Benin. Results Out of a total of 406 samples, 2.46% were positive. The isolates identified were multidrug-resistant Salmonella spp. to penicillins, first generation cephalosporins and some aminoglycosides. All Salmonella isolates produced inv A gene of 284 bp, fim A of 85 bp and stn of 260 bp. The spvC gene (571 bp) was present in 10% of the isolates whereas the spvR gene (310 bp) was found in 20% of the isolates. The control strain possessed all the tested genes. The invA gene implies that strains are able to invade epithelial cells. The fimA and stn genes present in all isolates show that they are capable of causing gastrointestinal illness in humans. The presence of spvC and spvR genes suggests the possibility of these strains to produce toxins. Electronic supplementary material The online version of this article (10.1186/s13104-019-4341-x) contains supplementary material, which is available to authorized users.

Two bacillus Calmette-Guérin (BCG)-susceptible mouse strains, BALB/c and C57BL/6, were infected intravenously with Mycobacterium intracellulare, M. avium or M. scrofulaceum and monitored during 3 months for mycobacterial replication and antibody and Th1-type cytokine production in response to cytoplasmic and secreted antigens from M. bovis BCG. Whereas initial colony-forming unit (CFU) counts of M. intracellulare and M. avium were higher in lungs than in spleen, the opposite was observed for M. scrofulaceum. Mycobacterium intracellulare was the most virulent species and its replication could not be controlled in either mouse strain. It also induced the strongest antibody response. Mycobacterium avium was eliminated in both mouse strains and M. scrofulaceum finally was eliminated in C57BL/6 but multiplied in spleen from BALB/c mice. Significant sustained interleukin-2 and interferon-g production towards BCG antigens was only found in M. scrofulaceum infection. As in BCG-vaccination, M. scrofulaceum-infected C57BL/6 mice demonstrated a higher response towards whole BCG culture filtrate, BCG extract and purified antigen 85 complex (Ag85) from BCG than did BALB/c mice. The data suggest that the presence of M. scrofulaceum in the environment may possibly interfere in genetically predisposed subjects with BCG vaccine and its protective efficacy against M. tuberculosis.

CD8 ؉ T cells are essential for protection against mycobacteria, as is clearly demonstrated by the fatal outcome of experimental infection of ␤-2 microglobulin knockout mice. However, the mechanisms and antigens (Ags) leading to CD8 ؉ T-cell activation and regulation have been poorly characterized. Here we show that, upon immunization of major histocompatibility complex (MHC)-congenic mice with Mycobacterium bovis bacillus Calmette-Guérin (BCG), a cytotoxic response against BCG culture filtrate (CF) Ags (CFAgs) is induced in H-2 b and H-2 bxd haplotypes but not in H-2 d haplotype. This response is mediated by CD8 ؉ T cells and absolutely requires the activation of CD4 ؉ T cells and their secretion of interleukin 2. The lack of cytotoxic response in H-2 d mice cannot be explained by impaired cytokine production or by a defect in Ag presentation by H-2 d macrophages. Using the MHC class I mutant B6.C-H-2 bm13 mouse strain, we demonstrate that cytotoxic T lymphocytes (CTLs) recognize CFAgs exclusively in association with D b molecules. These Ags are cross-reactive in mycobacteria, since BCG-induced CTLs also recognize macrophages pulsed with CF from Mycobacterium tuberculosis H37Rv and H37Ra and from two virulent strains of M. bovis. Moreover, immunization with Mycobacterium kansasii induces CTLs able to lyse macrophages pulsed with BCG CF. Finally, we have found that these Ags can be characterized as hydrophilic proteins, since they do not bind to phenyl-Sepharose CL-4B. Our results indicate that MHC-linked genes exert a profound influence on the generation of CD8 ؉ CTLs following BCG vaccination.

The microbiological and nutritional characterization of locust bean pulp powder (Parkia biglobosa) was investigated. Bacteria and fungi were isolated from this product. The bacteria isolated were essentially fecal coliforms. The fungal isolates were Aspergillus niger, Aspergillus ochraceus and Penicillium digitatum. The mean total plate count of samples was 2.8 × 10 3 cfu/g, while the mean coliform total count was lower than 10 cfu/g and the mean fungal count was 1.9 × 10 3 cfu/g. The respective mean moisture content and total acidity in locust bean pulp powder were 24.16 ± 2.45 and 2.10 ± 0.95%. Nutritional analysis showed that locust bean pulp powder has interesting nutritional potential. Carbohydrate content (6.28 ± 0.67%), protein content (4.129 ± 0.328%), carotenoid content (0.154 ± 0.03%) and the presence of minerals such as calcium (0.166 ± 0.005%), sodium (0.228 ± 0.006%), potassium (1.60 ± 0.071%) and magnesium (0.144 ± 0.002%) allowed its application as supplement in infant feeding in rural areas. Anti-nutritional factors such as oxalate and phytate were detected in samples, and values were lower than established toxic level. Finally, more attention should be made to its microbial quality in order to preserve children's health.

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