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V Seagroatt

Publications and source records attributed to V Seagroatt.

At least 73 records · Page 4Linked to original sources
PubMed1985

The standardization of infectivity titrations of poliovaccines--a WHO collaborative study.

The reproducibility of a method for infectivity titrations of live poliovaccines using microtitre plates was investigated in a WHO collaborative study involving eight laboratories. The large variation (up to 100-fold) in estimates of infectivity observed between laboratories using their local methods of assay was reduced to no more than fourfold when a common method was used. However, expressing infectivities relative to those of the monovalent reference viruses improved the agreement between the laboratories irrespective of the titration method employed. On the basis of these results, WHO adopted the common method used in the study as its recommended method for poliovirus titrations and established the preparations studied as international reference materials for the infectivity titrations of live poliovaccines.

Animals↗
PubMed1984

A collaborative study on the use of single radial immunodiffusion for the assay of rabies virus glycoprotein.

The single radial immunodiffusion (SRD) technique has been applied to the assay of the glycoprotein content of rabies vaccines produced in cell cultures. Fourteen laboratories in seven countries participated in a collaborative study to evaluate the reproducibility of the SRD technique; some laboratories also examined vaccines in the mouse protection (NIH) test and by enzyme immunoassay. Good agreement was found between potency estimates using the SRD technique: the geometric coefficients of variation for combined potency estimates of all laboratories were about 10%. SRD assays appear to have a role for the in vitro assay of antigen content of vaccine and could complement results obtained in in vivo assays which are subject to wide variability.

Animals↗
PubMed1984

A collaborative study on RAST inhibition using a common method.

A collaborative study was carried out to determine the reproducibility of the inhibition form of the radioallergosorbent test (RAST). Seven laboratories were provided with three coded extracts of cocksfoot (Dactylis glomerata) pollen. All laboratories used a common method of RAST inhibition and were supplied with all reagents required to carry out the assays. In addition, four laboratories used local methods of RAST inhibition. Potency estimates were in reasonable agreement between laboratories when the study method was used but insufficient data were available to assess reproducibility when local methods were used. Two extracts prepared from the same source material were found to have parallel log dose-response lines but the line for the unrelated extract was steeper in all but one of the assays. This finding was an indication that the third extract differed qualitatively from the other extracts. It was concluded that the use of a study method of RAST inhibition resulted in good agreement between potency estimates obtained by different laboratories.

Allergens↗
PubMed1983

Surveys of rubella antibodies in young adults and children.

22 000 serum samples from university students and young adult blood donors collected between 1969 and 1980 were tested for antibody to rubella virus. Of the women born in 1956 and after (i.e., those eligible for rubella vaccine at school) the proportions seronegative ranged from 3% to 6% in different years, compared with 12-20% in men of the same age groups. Serum samples from schoolchildren were also tested: 40-50% of girls and boys aged 10-11 years were seronegative--percentages similar to those before the introduction of vaccine. However, only 2-6% of 15-year-old girls (who would have been offered vaccine) were seronegative compared with 20-30% of 15-year-old boys. These results indicate that the rubella vaccination programme in the U.K. is having a significant impact on the immunological status of young women of childbearing age but that a large number of women remain potentially susceptible.

Adolescent↗
PubMed1983

A W.H.O. collaborative study of in vitro and in vivo methods for the assay of yellow fever vaccines.

An international collaborative study was carried out to compare the plaque assay in monolayer cell cultures with the mouse assay for the potency testing of yellow fever vaccines. Twelve laboratories assayed four preparations of yellow fever virus by both methods. Differences were found between estimates of infectivities obtained by different laboratories using the plaque assay. There was also large variation between the estimates of mouse LD50 obtained by different laboratories. However, expressing potencies of the preparations relative to a common preparation greatly reduced the variation between laboratories for both the plaque and the mouse tests; it also resulted in remarkably close agreement between the methods.

Animals↗
PubMed1979

Effect of rubella vaccination programme on serological status of young adults in United Kingdom.

Antibody to rubella virus was measured in over 10,000 serum samples collected in 1976, 1977, and 1978 from young adult blood donors and university students. The incidence of seronegatives was lower (4--7%) among females born in 1956 and subsequently--i.e., among the age groups offered rubella vaccine at school--than among females born before 1654 (11--20%). The incidence of seronegatives among males in the 1977 and 1978 surveys had the opposite trend, with a higher proportion of seronegatives in younger males, born in 1956 and subsequently, than in older males. The findings provide evidence that the rubella vaccination programme in the U.K. is having a significant impact on the immunological status of young females of childbearing age. Nevertheless too high a proportion of young females remains potentially susceptible to rubella.

Adolescent↗
PubMed1977

The use of single-radial-haemolysis for rubella antibody studies.

The use of a single-radial-haemolysis technique for the detection of antibody to rubella virus is described. The single-radial-haemolysis test was compared with the standard HI methods for the detection of antibody to rubella virus. A close correlation between the two methods was observed in a survey of over two thousand serum samples and the study indicated that single-radial-haemolysis was highly satisfactory as an assay method for IgG antibodies to rubella virus. It was found that the immuno-globulins active in SRH tests sedimented in the 7S range in sucrose rate gradients and were presumably immunoglobulins of the IgG class, but 19S immunoglobulins did not produce haemolysis.

Adolescent↗