ABSTRACT
BACKGROUND: Prevention of Helicobacter pylori infection may help to control related gastritis, peptic ulcer and cancer. Of the possible preventive measures, immunization was successfully employed in various animal studies. However, no immunization protocol has been accepted for humans. A better characterization of the immune response against the pathogen may be required before a human vaccine is developed. AIM: To identify bacterial proteins which induce an immune response in infected humans or H. pylori-immunized rabbits. METHODS: An expression library of H. pylori genes was screened with sera from infected humans and from immunized rabbits. Positive clones were partially sequenced and identified on the basis of a homology search of a H. pylori genome database. Encoded proteins were expressed directly from positive clones and analyzed by SDS-PAGE/Western blot techniques. RESULTS: 114 positive clones were isolated: 79 by screening with human sera and 35 by screening with rabbit sera. Western blot analysis demonstrated that selected clones encoded one or more strongly immunoreactive proteins. 64 clones selected with human sera had no counterparts among clones from screening with rabbit serum. 13 of these clones encoded a total of 21 unknown H. pylori proteins. 17 clones selected with rabbit sera were not immunostained with human sera. They represent 2 various regions of the H. pylori genome which encoded 3 bacterial proteins of unknown function. CONCLUSIONS: Screening of H. pylori expression library identified immunogenic proteins - potential vaccine antigens.
Subject(s)
Antigens, Bacterial/immunology , Bacterial Proteins/immunology , Genes, Bacterial , Helicobacter pylori/immunology , Animals , Bacterial Proteins/genetics , Blotting, Western , Cloning, Molecular , DNA, Bacterial/analysis , Gene Expression , Genomic Library , Helicobacter Infections/immunology , Helicobacter Infections/microbiology , Helicobacter Infections/prevention & control , Helicobacter pylori/genetics , Humans , Polymerase Chain Reaction , RabbitsABSTRACT
The mutation lg of phage P2 has been located on the genetic map of P2 to the right of, and closely linked to, the del2 deletion, probably within tail gene F. The lg mutation causes larger burst sizes, compared with the wild type, especially at high incubation temperatures. The frequency of defective particles is lower in preparations of P2 lg than in those of wild type P2. It seems that the mutation lg improves the efficiency of particle assembly.
Subject(s)
Coliphages/genetics , Defective Viruses , Mutation , Genetics, MicrobialABSTRACT
The reverse mutation to the wild type of lambda sus 9 and T4 AM B17 bacteriophages, grown in bacteria prelabeled with 35S and stored at--196 degrees, was studied. No mutagenic effect of 35S was observed in both, lambda and T4 bacteriophages. It is suggested that there is no influence of 35S disintegrations on the properties of DNA polymerase to which the mutagenic activity could be attributed.
