Hepatitis C virus (HCV) is a major health problem. However, the mechanism of hepatocyte infection is largely unknown. We demonstrate that the dendritic cell (

BackgroundAcellular pertussis vaccines do not control pertussis. A new approach to offer protection to infants is necessary. BPZE1, a genetically modified Bordetella pertussis strain, was developed as a live attenuated nasal pertussis vaccine by genetically eliminating or detoxifying 3 toxins.MethodsWe performed a double-blind, placebo-controlled, dose-escalating study of BPZE1 given intranasally for the first time to human volunteers, the first trial of a live attenuated bacterial vaccine specifically designed for the respiratory tract. 12 subjects per dose group received 103, 105 or 107 colony-forming units as droplets with half of the dose in each nostril. 12 controls received the diluent. Local and systemic safety and immune responses were assessed during 6 months, and nasopharyngeal colonization with BPZE1 was determined with repeated cultures during the first 4 weeks after vaccination.ResultsColonization was seen in one subject in the low dose, one in the medium dose and five in the high dose group. Significant increases in immune responses against pertussis antigens were seen in all colonized subjects. There was one serious adverse event not related to the vaccine. Other adverse events were trivial and occurred with similar frequency in the placebo and vaccine groups.ConclusionsBPZE1 is safe in healthy adults and able to transiently colonize the nasopharynx. It induces immune responses in all colonized individuals. BPZE1 can thus undergo further clinical development, including dose optimization and trials in younger age groups.Trial RegistrationClinicalTrials.gov NCT01188512

Activins are members of the transforming growth factor-␤ family of growth and differentiation factors. In this paper, we report the results of a structure-function analysis of activin A. The primary targets for directed mutagenesis were charged, individual amino acids located in accessible domains of the protein, concentrating on those that differ from transforming growth factor-␤2, the x-ray crystal structure of which is known. Based on the activities of the recombinant activin mutants in two bioassays, 4 out of 39 mutant proteins (D27K, K102A, K102E, and K102R) produced in a vaccinia virus system were selected for further investigation. After production in insect cells and purification of these four mutants to homogeneity, they were studied in bioassays and in cross-linking experiments involving transfected receptor combinations. Mutant D27K has a 2-fold higher specific bio-activity and binding affinity to an ActRIIA/ALK-4 activin receptor complex than wild type activin, whereas mutant K102E had no detectable biological activity and did not bind to any of the activin receptors. Mutant K102R and wild type activin bound to all the activin receptor combinations tested and were equipotent in bioassays. Our results with the Lys-102 mutants indicate that the positive charge of amino acid 102 is important for biological activity and type II receptor binding of activins.

Lactobacillus amylovorus LMG P-13139, isolated from corn steep liquor, produces two bactericidal peptides with respective estimated molecular masses of 4.5 and 6.0 kDa upon denaturing sodium dodecyl sulfatepolyacrylamide gel electrophoresis. The antimicrobial activity detected in the fermentation supernatant fraction of L. amylovorus LMG P-13139 was heat stable (20 min, 121؇C), displayed a narrow inhibitory spectrum, and was sensitive to proteinase K, trypsin, and ␣-chymotrypsin but insensitive to ␣-amylase, lysozyme, catalase, and lipase. The 4.5-kDa bacteriocin was purified and characterized and designated lactobin A. Lactobin A was isolated as a floating pellicle from culture supernatant brought to 35% saturation with ammonium sulfate. Upon this ammonium sulfate treatment, crude lactobin A was incorporated, together with Tween 80 as a major contaminant, in high-molecular-mass complexes sized at approximately 670 kDa by gel filtration chromatography. Contaminating fatty acids were removed from these micelles by a simple one-step methanol-chloroform extraction without loss of activity. Both inhibitory peptides were separated in an isocratic isopropanol gradient on a PepRPC 5/5 reversed-phase column, and both peptides retained activity towards Lactobacillus helveticus ATCC 15009 upon separation. Lactobin A has a molecular mass determined by electrospray mass spectrometry of 4,879 ؎ 0.69 Da. Its peptide chain contains 50 unmodified amino acids, of which 26% are glycine residues and 40% are hydrophobic residues (A, V, L, I, and P). It displays the highest structural homology (42% identity and 28% similarity) with the lafX gene product, encoded by the second open reading frame of the lactacin F operon. These data strongly indicate that lactobin A belongs to the class IIb bacteriocins according to the classification of Klaenhammer.

A 330-residue carboxy-terminal antigenic fragment of the Toxoplasma gondii 54-kDa rhoptry protein (ROP2) was expressed in Escherichia coli as a fusion polypeptide containing a 48-amino-acid sequence derived from phage lambda protein Cro and E. coi protein LacI followed by six consecutive histidyl residues. Metal chelate affinity chromatography provided an easy way to isolate the recombinant product in a highly purified form (>95%). When this material was used to develop an immunoglobulin G (IgG) enzyme-linked immunosorbent assay for diagnosis of toxoplasmosis, the test reached a sensitivity of 89%o. The sensitivity of the assay was similar whether the sera contained T. gondii-specific IgM or were devoid of such IgM. It was also found that ROP2 is a conserved antigen since antibodies against the recombinant antigen could be detected in mice experimentally infected with 11 independent T. gondii isolates originating from infected human tissues tested. Thus, the 54-kDa rhoptry antigen could advantageously complement other previously described T. gondii antigens for the development of more-sensitive and more-informative recombinant antigen-based tests for toxoplasmosis diagnosis.