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Biomedical subjects

J V Scott

Publications and source records attributed to J V Scott.

15 recordsLinked to original sources
PubMed1993

Biochemical and immunological properties of two forms of pertactin, the 69,000-molecular-weight outer membrane protein of Bordetella pertussis.

Two apparent isoforms of the virulence-associated 69,000-molecular-weight protein pertactin were purified from Bordetella pertussis. Mass spectrometry showed a difference of 2,060 Da, which may result from differential C-terminal cleavage of a larger precursor. Both forms were protective in a mouse model, eliciting bactericidal antibodies and reducing respiratory tract colonization.

Amino Acid Sequence↗
PubMed1992

The agglutinin response to whole-cell and acellular pertussis vaccines is Bordetella pertussis--strain dependent.

OBJECTIVE: To determine the significance of the Bordetella pertussis strain used as the antigen in the agglutinin assay for the evaluation of pertussis vaccines. DESIGN: Randomized, double-blind study. SETTING: Health maintenance organization clinics, primary care clinic at a referral hospital, and private practices in Los Angeles County, California. PARTICIPANTS: Forty healthy infants. SELECTION PROCEDURES: Convenience sample. INTERVENTIONS: Twenty infants received whole-cell pertussis-component diphtheria-tetanus-pertussis vaccine (DTP), and 70 infants received acellular pertussis-component diphtheria-tetanus-pertussis vaccine (APDT) at ages 2, 4, and 6 months. MEASUREMENTS: The agglutinin assay was performed using three separate B pertussis strain preparations: (1) strains 130 and 138 in equal quantities, the constituents of the DTP vaccine, (2) strain 460, and (3) strain Tohama, the constituent of the APDT vaccine. RESULTS: The agglutinin titers were highly strain dependent; in both groups of vaccinees at both ages the Tohama values were highest, followed by strain 460 and then strains 130/138. The vaccine groups had comparable titers at age 2 months regardless of the assay antigen used. However, at age 7 months, after three immunizations, the DTP group geometric mean titer was more than 10 times greater than that of the ADPT group using strains 130/138, but only 2.6 times higher using strain 460 and almost equivalent using Tohama strain. CONCLUSION: Vaccine group agglutinin value comparisons strongly depend on assay antigens used.

Agglutination Tests↗
PubMed1991

Clinical trials in the United States and Japan with the Lederle-Takeda and Takeda acellular pertussis-diphtheria-tetanus (APDT) vaccines. The Multicenter APDT Vaccine Study Groups.

The results of the following studies are reported: a longitudinal double blind trial comparing Lederle-Takeda APDT vaccine with Lederle DTP vaccine in two, four and six month old infants; two double blind similar APDT vs DTP trials in 18 month old and four to six year old children; a large longitudinal open trial with APDT in two, four and six month old infants and a household contact efficacy trial with Takeda APDT in Japan. APDT vaccine recipients had a lesser frequency and less severe reactions than whole cell vaccine recipients. Antibody responses to lymphocytosis-promoting factor and agglutinogens were higher in DTP recipients; APDT recipients had a better serologic response to filamentous hemagglutinin. Equivalent 69K protein antibody responses were seen. Vaccine efficacy in the household contact study was 98% (95% CI = 84% to 99%) against classical pertussis and 81% (95 CI = 64% to 90%) if all respiratory illnesses are considered.

Antibodies, Bacterial↗
PubMed1990

Preliminary X-ray crystallographic analysis of holotoxin from Bordetella pertussis.

Pertussis (whooping cough) is a serious infectious disease caused by the bacterium Bordetella pertussis. One of the major virulence factors is a protein known as pertussis toxin, which is composed of six subunits, with a total molecular weight of 106,000. Enzymatic transfer of ADP-ribose from NAD to a family of GTP-binding proteins is effected by the largest subunit (S1 or the A monomer), while binding of host cells and entry of S1 to the interior is a function of the other subunits (the B oligomer). The holotoxin crystallizes in the orthorhombic space group P2(1)2(1)2(1), with unit cell dimensions a = 98.4 A, b = 164.2 A and c = 195.2 A. The crystals are suitable for high-resolution X-ray diffraction analysis.

Bordetella pertussis↗
PubMed1990

Protective efficacy of the Takeda acellular pertussis vaccine combined with diphtheria and tetanus toxoids following household exposure of Japanese children.

The clinical efficacy of an acellular pertussis vaccine containing lymphocytosis-promoting factor, filamentous hemagglutinin, agglutinogens, and the 69-kd outer membrane protein, combined with diphtheria and tetanus toxoids and adsorbed onto an aluminum salt, was assessed in a household contact study. The occurrence of pertussis 7 to 30 days following home exposure among 62 previously vaccinated children was compared with that among 62 unvaccinated children similarly exposed. Classic whooping cough was diagnosed in 43 unimmunized children, and 1 vaccinated child experienced a 5-week illness that was probably pertussis (efficacy, 98%; 95% confidence interval, 84% to 99%). A few children in each group incurred respiratory illnesses that may have represented mild, atypical pertussis; including these as probable pertussis, vaccine efficacy was 81% (95% confidence interval, 64% to 90%). It is concluded that prior immunization with this four-component pertussis vaccine combined with diphtheria and tetanus toxoids is highly efficacious in preventing pertussis.

Bias↗
PubMed1990

Comparison of an acellular pertussis-component diphtheria-tetanus-pertussis (DTP) vaccine with a whole-cell pertussis-component DTP vaccine in 17- to 24-month-old children, with measurement of 69-kilodalton outer membrane protein antibody.

Healthy 17- to 24-month-old children, previously immunized with three doses of whole-cell diphtheria-tetanus-pertussis (DTP) vaccine, were enrolled in a multi-center double-blind, randomized study comparing a DTP vaccine with an acellular pertussis-component (APDT) and a conventional whole-cell pertussis-component DTP vaccine. Thirty-eight children received APDT vaccine, and 37 children received DTP vaccine. APDT vaccine recipients had significantly less local pain and warmth than DTP vaccine recipients. Antibody responses to lymphocytosis-promoting factor were similar in the two groups. The APDT vaccine recipients had a higher IgG antibody response to filamentous hemagglutinin than the DTP vaccinees had. Equivalent agglutinin responses were seen in the two groups. The APDT vaccine recipients had a significantly better antibody re-enzyme-linked immunosorbent assay, than DTP vaccinees had 1 month and 1 year after immunization. This APDT vaccine was immunogenic and caused fewer local reactions than conventional DTP vaccine when administered as a fourth dose to 17- to 24-month-old children.

Agglutinins↗
PubMed1982

Enhanced yields of measles virus from cultured cells.

Conditions for increasing the yield of measles virus from cultured cells have been investigated. Important factors for high virus yields were found to be cell type, incubation at 33 degrees C, concentration of serum in the medium, use of virus as inoculum within five passages of plaque purification, and repeated harvesting of the virus-containing medium at 12 h intervals after extensive virus-induced cell fusion had occurred. Under these conditions, Vero cells infected with the Edmonston strain of measles virus yielded a total of 2.98 X 10(9) plaque-forming units (p.f.u.) of released virus, which is equivalent to 270 p.f.u./cell. A similar amount of cell-associated virus was produced.

Animals↗
PubMed1980

A temperature-sensitive single-stranded DNA-binding protein from Escherichia coli.

A temperature-sensitive single-stranded DNA-binding protein (SSB) has been purified from mutant Escherichia coli (ssb-1) cells by use of affinity chromatography on blue dextran-Sepharose. An altered amino acid sequence in the mutant protein is apparent in tryptic digests, confirming that the ssb mutation is in the structural gene. The mutant protein is less effective than the wild type in protecting single-stranded DNA from nuclease S1 digestion and in inhibiting DNA-dependent ATPases. The purified protein supports replication of phage G4 DNA in vitro at 30 degrees C, although higher levels of mutant protein, 4-fold higher than wild type, are needed to do so. The mutant protein becomes less active in supporting replication above 30 degrees C and becomes inactive at 42 degrees C within 1 min. Activity is restored upon return to 20 degrees C. Despite its temperature sensitivity in vivo and in vitro, the mutant binding protein can renature fully after exposure to 100 degrees C. Thus, the mutant protein is both heat-stable and functionally temperature-sensitive.

DNA Helicases↗
PubMed1979

Antigenic variation in visna virus.

Two antigenic variants of visna virus were isolated sequentially from a single sheep inoculated with a plaque-purified strain of virus designated 1514. The genetically stable variants, LV1-1 and LV1-4, are of two classes: LV1-1 is partially neutralized by antibody to the inoculum strain 1514, while LV1-4 is not neutralized by antibody to 1514. The genetic mechanism responsible for generating the antigenic variants was investigated by comparing the chymotryptic and tryptic maps of the envelope glycoprotein gp135 and core polypeptides (p30, p16, p14), and by comparing the pattern of large oligonucleotides produced by digestion of the RNAs by T1 ribonuclease. We show that only the peptide maps of gp135 differ among strains, that the number of peptide fragments altered is small and that gp135 is the polypeptide that elicits neutralizing antibody. The maps of the RNAs are identical. We conclude that mutation in the glycoprotein gene rather than recombination is more probably responsible for antigenic variation, and speculate on the special aspects of visna virus replication relevant to this phenomenon.

Amino Acid Sequence↗
PubMed1975

Radioimmunoassay of human serum antibody specific for adenovirus type 5-purified fiber.

A radioimmunoassay (RIA), utilizing a second antibody to separate immune complexes, was developed to provide a sensitive and specific measure of serum antibody to adenovirus type 5 (Ad 5) fiber. Purity of fiber antigen was ascertained by sodium dodecyl sulfate urea-polyacrylamide gel electrophoresis and isoelectric focusing in ampholyte pH gradients. After labeling with 125I to high specific activity, the iodinated fiber did not exhibit loss of antigenic reactivity and remained stable for 3 weeks when stored at minus 20 degrees C with supplemental protein. Rabbit anti-Ad 5 serum with a neutralization titer of 1:320 precipitated 50% of the labeled fiber at a serum dilution of 1:50,000 when tested by the RIA. In competition assays as little as 0.5 ng of unlabeled fiber per millimeter was sufficient to inhibit the 125I fiber-antibody reaction. Serum specimens from 20 volunteers, obtained before and after vaccination with purified Ad 5 fiber or hexon subunit vaccine, were tested by RIA, hemagglutination-inhibition (HI), and neutralization tests. A comparison of mean antibody titers of post-inoculation sera showed that the RIA was 300 and 1000 times more sensitive than the HI and neutralization tests, respectively. Moreover, 19 of the men who were negative by the standard serologic tests before vaccination were shown to have anti-fiber antibody, with a mean RIA titer of 1:1028. Specificity of the RIA was demonstrated by the lack of an increase in antibody to Ad 5 fiber among those individuals vaccinated with the hexon subunit. Thus, the development of a highly sensitive and reproducible RIA allows for the detection of antibody specific for the Ad 5 fiber in serum which contains antibodies to the different virion antigenic determinants associated with Ad 5.

Adenoviridae↗