Biomedical subjects
Publications and source records attributed to J M Fournier.
A method is described for typing Staphylococcus aureus capsular polysaccharides that is based on direct bacterial cell agglutination and immunoprecipitation of cell extracts with monospecific antisera. Encapsulated strains were identified by their inagglutinability with teichoic acid antisera. The typing sera reacted specifically with extracts of eight prototype strains.
Bordetella pertussis bacterial cells, bacterial extracts, and concentrated culture supernatant fluid were comparatively examined for histamine sensitizing and leucocytosis promoting activities, toxicity (mouse weight gain test), immunoprotective potency and lipopolysaccharide bioassay. The activity of histamine sensitizing factor always paralleled that of leucocytosis promoting factor. In contrast, important differences were demonstrated regarding the toxicity and protective activity of the three preparations. Culture supernatant was more toxic and less protective than either bacterial cells or cell extract. Although the latter had lower protective potency than whole cells, its lower toxicity might lead to its consideration as a possible potential vaccine.
Clinical isolates of Staphylococcus aureus have been previously classified into eight types on the basis of their capsular polysaccharide. The high prevalence of the type 8 capsular polysaccharide among bacteremic isolates suggests the importance of this capsular antigen in staphylococcal disease. The capsular polysaccharide was purified from extracts of three clinical isolates of S. aureus type 8 of different geographic and temperal origin by ion-exchange chromatography and gel filtration. Gas chromatography, gas chromatography-mass spectrometry, and 13C-nuclear magnetic resonance showed that the type 8 capsular polysaccharide is composed of O-acetyl groups, N-acetylfucosamine, and an aminouronic acid similar to N-acetylgalactosaminouronic acid. The purified polysaccharide reacted only with type 8 antiserum in double diffusion experiments. Our analysis shows that the type 8 polysaccharide is both chemically and serologically distinct from teichoic acid and previously characterized polysaccharides of S. aureus.
Haemophilus influenzae type b is the most common cause of bacterial meningitis in children. Intranasal or intraperitoneal inoculation of infant rats with Haemophilus influenzae type b results in bacteremia and meningitis and has been proved to be a reproductible model of the human disease. For these reasons, it was of interest to use rats as experimental model for the study of anti-Haemophilus influenzae type b vaccine. Immune serum against Haemophilus influenzae type b cell surface extracts was prepared on rabbit. In a first experiment, pregnant rats were passively immunized with either immune rabbit serum or normal rabbit serum or saline. In a second experiment, suckling rat mothers were passively immunized with either immune rabbit serum or normal rabbit serum or saline. All infant rats were inoculated intraperitoneally at 6 days of age with Haemophilus influenzae type b. Bacteremia was determined in all infected rats 24 h after challenge. Only infant rats from immune serum-treated mothers were protected. This protection may be transferred from mother to young rat either before of after the birth.
Previous work has demonstrated the capsular serotypic specificity of the protection conferred on mice by Klebsiella pneumoniae ribosomal preparations. The data in these studies support the hypothesis that capsular polysaccharide plays at least some role in the specificity of the protection conferred by ribosomal preparations. In this investigation, the presence of capsular polysaccharide and lipopolysaccharide in K. pneumoniae ribosomal preparations was demonstrated by using immunodiffusion tests. Lipopolysaccharide content was determined for mice treated with actinomycin D. The serotype of O antigen did not play a role in the orientation of the specificity of the protection. The possibility that lipopolysaccharide might act as an adjuvant was not unlikely since the ribosomal preparations which contained the greatest amounts of lipopolysaccharide appeared to be the most immunoprotective preparations. Ribosomal preparations extracted from a noncapsulated mutant of K. pneumoniae did not protect mice. This finding suggested that capsular polysaccharide might play a role in the immunoprotective activity of ribosomes. This hypothesis was tested by using K. pneumoniae K2 bacteriophage-associated-glycanase, which specifically hydrolyzed K. pneumoniae K2 capsular polysaccharide and thereby suppressed the immunoprotective activity of K. pneumoniae K2 ribosomal preparations. In contrast, the K2 bacteriophage-associated glycanase did not interfere with the immunoprotective activity of K. pneumoniae K1 ribosomal preparations. These results clearly demonstrate that capsular polysaccharide, which is an extraribosomal antigen, is involved in the immunoprotective activity of K. pneumoniae ribosomal preparations.
Cell surface preparations and ribosomal preparations were extracted from Klebsiella pneumoniae. Agar gel diffusion with antisera to cell surface preparations or ribosomal preparations indicated common antigenic components among the preparations. Lipopolysaccharide and capsular polysaccharide were identified in the cell surface preparations. These results and the previous identification of lipopolysaccharide and capsular polysaccharide in ribosomal preparations suggest that these antigens are responsible for the immunochemical cross-reactivity observed among these two bacterial extracts. Active protection could be induced in mice by these two preparations. On a dry-weight basis, cell surface preparations provided better immunoprotective activity than did ribosomal preparations. However, the 50% protective dose of both preparations is practically the same on the basis of their capsular polysaccharide content. These results are consistent with the hypothesis that the immunoprotective moiety of ribosomal preparations is the contaminating cell surface antigens. Furthermore, the low level of nucleotidic components detected in purified cell surface preparations led us to infer that the immunoprotective activity of capsular polysaccharide may not be dependent on the adjuvant activity of ribonucleic acid. The involvement of capsular polysaccharide in the immunoprotective capacity of cell surface preparations is demonstrated either by using a degradation of this antigen by K. pneumoniae bacteriophage K2-associated glycanase or by using a preparation extracted from a noncapsulated mutant of K. pneumoniae. Nevertheless, the low protective ability of purified capsular polysaccharides is in contrast to its greater activity when induced in bacterial cell surface preparations. The protective activity of K. pneumoniae capsular polysaccharide may be dependent on its association with other surface antigenic components present in cell surface preparations or may be dependent on its native form in the bacterial cell surface.
Two peaks were obtained by cesium chloride density gradient ultracentrifugation of Klebsiella pneumoniae ribosomal preparations. Peak I contained capsular polysaccharide, lipopolysaccharide, protein, and less than 0.5% ribonucleic acid. Peak II consisted mainly of ribonucleic acid, with low amounts of protein and capsular polysaccharide. Expressed as capsular polysaccharide content, the 50% protective dose of peak I and of nonfractionated ribosomal preparations was nearly constant (2.6 and 1.2 ng, respectively). Since peak I contained less than 0.5% ribonucleic acid, these results provide evidence that ribosomal ribonucleic acid is not required for protection of mice by K. pneumoniae capsular polysaccharide which contaminates ribosomal preparations.
Klebsiella pneumoniae ribosomal preparations protect mice immunized by the subcutaneous route against an intraperitoneal challenge of 100 50% lethal doses. The minimal protective doses are 5 and 0.4 micrograms of proteins for preparations extracted from strains of capsular serotypes 1 and 2, respectively. This difference in protective activity is also found in bacteria killed by Formalin. The protective activity of these preparations is not diminished by their purification on sucrose gradient, which eliminates most of the membrane vesicles which are visible by electron microscopy. The use of four strains of K. pneumoniae belonging to capsular serotypes 1 and 2 allowed us to show that the immunoprotective capacity of the ribosomal preparations was specific to the capsular serotype of the origin strain. This was confirmed by experiments in which the serum of immunized mice was transferred passively. The experimental data favor the presence in the ribosomal preparation of antigens belonging to the bacterial surface and resisting elimination by ultracentrifugation on sucrose gradient. Those surface antigens (possibly capsular polysaccharide) at least play a role in the orientation of the specificity of the protection induced by the ribosomal preparations.
A new technic or immunization against Newcastle disease in chicken was developed: this method consists of dispersing lyophilized products by aerosols. One to fourteen day old chickens, with and without parental antibodies, were vaccinated with increasing amounts (10(-1) to 10(5)EID50) of HB1 and LaSota attenuated viruses. 10(4)EID50, inhaled theoretical dose, gave better results when the animals were challenged with the virulent strain. Under laboratory conditions, no respiratory problems occurred in vaccinated animals; but there is 10 to 20% mortality among animals treated by aerosols in poultry houses, because of respiratory diseases developed after vaccination.
Day-old chickens with Newcastle disease maternal antibodies are separated in two batches. One batch (S) is vaccinated by liquid spray method with HB1 strain: the other one (NS) is not vaccinated. At 2, 3 or 4 weeks subgroups from S and NS batches are vaccinated with HB1 strain by dry aerosol method. Serological controls reveal an important increase of Newcastle antibodies within two weeks after dry aerosol vaccination. Then a drop of the antibody quantities is observed during weeks 2 to 4 post dry aerosol vaccination. In the following weeks, the antibody level increases very slowly.
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Clinical surveys have indicated the predominance of type 5 and type 8 capsular polysaccharides among clinical isolates of Staphylococcus aureus. The type 5 capsular polysaccharide was extracted from three clinical isolates of S. aureus grown on solid media, and purified by ion exchange chromatography and gel filtration. Chemical analysis showed that the type 5 capsular polysaccharide is composed of N-acetylfucosamine and N-acetylhexosaminuronic acid. Immunodiffusion and 13C nuclear magnetic resonance experiments showed that the type 5 capsular polysaccharide is both immunologically and chemically distinct from the type 8 capsular polysaccharide and the teichoic acid of S. aureus.