An in vitro study of the susceptibility of cells from a meningioma of human origin for measles virus.

A cell culture from a meningioma of human origin was found permissive for the Edmonston strain of measles virus. Virus was isolated from the supernatant of infected cell sheet as soon as 48 hr post-inoculation. Cytopathic effect, observed by light microscopy, exhibited syncitia plus intracytoplasmic and intranuclear inclusions. Electron microscopy enabled viral nucleocapsids to be observed first in the cytoplasm and secondly within the nucleus of infected cells.

The epidemiology of chlamydial infections in childhood: a serological investigation.

Blood samples from 382 children between the ages of one and 15 years were tested for anti-chlamydial antibody. A low prevalence of antibody against Chlamydia trachomatis was found among children under the age of seven years. Antibody against the Chlamydial agent C IOL-207 was rare before the age of five years, but was found with increasing prevalence in older children. It is suggested that the mode of transmission of the two agents is different and that C IOL-207 may be transmitted at school.

Indirect micro-immunofluorescence test for detecting type-specific antibodies to herpes simplex virus.

A rapid indirect micro-immunofluorescence test capable of detecting and differentiating type-specific antibodies to herpes simplex virus is described. The test proved highly sensitive and, in 80 patients with active herpes ocular infection, antibody was detected in 94%. No anti-herpes antibody was detected in a control group of 20 patients with adenovirus infections. Testing of animal sera prepared against herpes simplex virus types 1 and 2 and of human sera from cases of ocular and genital herpes infections showed that the test can differentiate antibodies to the infecting serotypes. Specimens of whole blood, taken by fingerprick, and eye secretions, both collected on cellulose sponges, could be tested by indirect micro-immunofluorescence. Anti-herpes IgG, IgM, and IgA can also be detected.

An evaluation of nine commercial EIA kits for the detection of measles specific IgG.

Nine commercial EIAs for measles-specific IgG were compared with haemagglutination inhibition (HI) and plaque reduction neutralization (PRN). A total of 174 sera selected, to give approximately half of the sera without measles antibody by HI, were tested by all EIAs and HI. However, there was sufficient volume of only 101 samples for testing by PRN. A dilution curve of the British Standard measles antibody serum was also tested by each EIA. Assays were evaluated qualitatively against a consensus EIA result, HI and PRN: Gull, Melotest and Behring EIAs performed best. Quantitative evaluation was by assessment of the characteristics of the standard dilution curve, and by plotting differences with PRN against mean: Gull and Melotest EIAs were best.

Evidence of chlamydial infection in infertile women with and without fallopian tube obstruction.

This study investigates the prevalence of Chlamydia trachomatis antibodies in 164 infertile women who underwent diagnostic laparoscopy and dye insufflation as part of routine infertility investigations. C. trachomatis antibodies were found in 36 (22%) of 164 infertile women, which was significantly more than the prevalence of antibodies in a control group (22 of 200, 11%). C. trachomatis antibodies were found in 25 (35.7%) of 70 infertile women who had laparoscopically verified peripheral tubal disease. This was significantly more than the prevalence of C. trachomatis antibodies in infertile women with normal fallopian tubes (6 of 52, 11.5%). The prevalence of C. trachomatis antibodies in infertile patients with laparoscopically verified cornual disease was similar to those without cornual disease. C. trachomatis was not isolated from any of the patients studied. This study confirms that past chlamydial salpingitis is associated with the development of peripheral fallopian tube obstruction with resultant infertility.

Transmission of chlamydiae by the housefly.

The ability of the housefly to carry viable Chlamydia trachomatis and to transmit a chlamydial ocular infection was studied under laboratory conditions. After feeding flies (Musca domestica) on suspensions of egg yolk sac infected with C. trachomatis serotypes A or B (responsible for hyperendemic trachoma) the agents were reisolated from flies' intestines for up to 6 hours and from their legs and/or proboscises for up to 2 hours. It was found that the viability of chlamydiae is dependent on the protective effect of yolk concentration in the original inoculum. Results of experiments with guinea-pig inclusion conjunctivitis as an animal model show that under laboratory conditions flies can readily transmit this chlamydial ocular infection from one animal to another. These results suggest that under field conditions flies can play an important role in the transmission of trachoma, particularly in areas with favourable conditions such as a large reservoir of infection among children with severe trachoma, copious eye discharge caused by trachoma and associated bacterial infections, a large fly population, and close proximity of children in large family groups.

Acute conjunctivitis caused by an atypical chlamydial strain: Chlamydia IOL 207.

A case of acute conjunctivitis in man caused by Chlamydia IOL 207 is described. Chlamydiae were isolated from the eye, and rising titres of type-specific antibodies to C. IOL 207, in serum and tears demonstrated an aetiological role for this agent. C. IOL 207 is an atypical chlamydial strain which serological studies suggest is widespread in some communities.

Antibodies to herpes simplex virus type I in intraocular fluids of patients with acute retinal necrosis.

The intraocular fluids and sera from three patients with acute retinal necrosis (ARN) and from 120 age-matched controls were tested for the presence of antibodies to herpes simplex virus type I (HSV-I). Antibodies to HSV-I were detected in both intraocular fluids and sera of two cases, and in intraocular fluids alone in one case of ARN. Among 120 control patients undergoing routine intraocular surgery antibodies to HSV-I were detected in the sera of 85 (79.2%) but in the intraocular fluids of only two (1.7%). The presence of antibody within the eye may indicate local antibody production, antibody sequestration within the eye, or damage to the blood ocular barrier.

Juxtapapillary choroiditis in association with rising antichlamydial antibody.

We present the case of a 21-year-old girl with a uniocular juxtapapillary choroiditis. During the course of her illness the titre of antichlamydial IgG increased from 1/32 to 1/4096 against Chlamydia trachomatis TRIC serotypes J and C, and antichlamydial IgM appeared in her blood. Toxoplasma dye test was positive at a level of 1/128 but no increase in the titre of antibody was detected during the course of her infection. The relevance of these findings to her ocular lesion is discussed.

Sequential antibody changes following ulcerative herpetic keratitis.

Blood and tear levels of immunoglobulins against herpes simplex virus (HSV) were examined in 28 patients with dendritic keratitis over a period of 28 days. By means of an indirect micro-immunofluorescent technique blood and tear HSV IgG were detected, but neither circulating HSV IgM nor local HSV IgA were found. Over a four-week interval non-diagnostic fluctuations of HSV IgG occurred in most patients, though seven (25%) developed a rising blood IgG titre. Tear IgG appeared to be an exudate from blood. HSV was isolated from 68% of corneal swabbings and 11% of conjunctival swabbings. This study provides guidelines for laboratory testing in recurrent herpetic keratitis.

Isolation of Chlamydia trachomatis from eye secretion (tears).

Shedding of Chlamydia trachomatis in the eye secretion (tears) of patients with either hyperendemic trachoma or paratrachoma was studied. The method of collection of eye secretion with cellulose sponges is proved to be simple, faster, and more practicable and yielded a higher rate of chlamydial isolation than aspiration. The chlamydial isolation rates in eye secretion in chlamydia-positive paratrachoma patients in London or trachoma patients in Iran was 84 and 49% respectively. It was found that the chlamydial isolation rate from eye secretion is directly related to the number of inclusions present in the conjunctival swabbings. The results of this study indicated that patients with moderate to severe hyperendemic trachoma or paratrachoma are the main reservoir of infection. In the developing countries of the Middle East and Africa the shedding of chlamydia in the eye secretion of persons with these diseases is a major factor in the transmission of them by means of flies, fingers, towels, or bed clothes.

Prevalence in human beings of antibodies to Chlamydia IOL-207, an atypical strain of chlamydia.

Samples of serum from 18353 persons from the U.K. and abroad, were tested for type-specific antibodies to Chlamydia spp. Antibodies to an atypical strain, Chlamydia IOL-207, were detected in each population tested. Overall, the prevalence of these antibodies (19.9%) was similar to that of antibodies to C. trachomatis (21.6%). In the U.K., antibodies to C. IOL-207 were rare in children under the age of 5 years but became more common with increasing age. In adults the prevalence of these antibodies increased annually between 1979 and 1984. Antibodies to C. IOL-207 were not associated with sexually transmitted disease and only rarely with ocular disease. Their association with a common complaint such as mild respiratory illness is postulated. The presence of these antibodies within a population may lead to the over-diagnosis of C. trachomatis infections or psittacosis if only genus-specific serological tests are used.

Comparison of a commercial enzyme immunoassay with plaque reduction neutralization for maternal and infant measles antibody measurement.

The most practicable assay for measurement of measles IgG (mIgG) in large numbers of sera is an enzyme immunoassay (EIA). To assess how EIA results would agree with those by the gold standard method of plaque reduction neutralization (PRN) we compared the results from the two methods in 43 pairs of maternal and umbilical cord sera, and sera from the corresponding infants when aged 11-14 months. In maternal-cord sera, the differences between mean antibody levels by EIA or PRN were not statistically significant, though in individual sera, differences could be large. However, agreement was less good for infants sera, in which levels of mIgG were very low. The conclusions of a study of transplacental transport of mIgG would not be affected by the use of either technique. When studying waning immunity in infants, PRN should be the method of choice, while results from studies using EIA should be interpreted with caution.

Calibration and use of an in-house anti-measles IgG standard serum.

For the purpose of research a large quantity of anti-measles IgG working reference serum was needed. A pool of sera from five teenagers was prepared and named Alexandre Herculano (AH). In order to calibrate the AH serum, 18 EIA assays were performed testing in parallel AH and the 2nd International Standard 1990, Anti-Measles Antibody, 66/202 (IS) in a range of dilutions (from 1/50 to 1/25,600). A method which compared parallel lines resulting from the graphic representation of the results of laboratory tests was used to estimate the power of AH relative to IS. A computer programme written by one of the authors was used to analyze the data and make potency estimates. Another method of analysis was used, comparing logistic curves relating serum concentrations with optical density by EIA. For that purpose an existing computer programme (WRANL) was used. The potency of AH relative to IS, by either method, was estimated to be 2.4. As IS has 5000 milli international units (mIU) of anti-measles IgG per millilitre (ml), we concluded that AH has 12,000 mIU/ml.

A European collaborative study to assess the proficiency of laboratory estimates of potency of live measles, mumps and rubella tri-valent vaccines.

A collaborative study involving 10 European laboratories was undertaken to assess the variability of estimates of the potency of measles, mumps and rubella tri-valent vaccines. The precision of assays as demonstrated by tests on duplicate samples was good; differences averaged around 0.2 log10 steps. Similarly, assay to assay variation within laboratories was small with most achieving consistency around 5% over three assays. In contrast, overall median variations in potency between laboratories were around 1.0 log10 for measles, 3.0 log10 for mumps and 2.0 log10 for rubella. Unexpectedly, the variations in estimates for measles and rubella were not improved when potencies were expressed relative to reference preparations. However, for mumps variability was reduced by using a reference but only for the vaccines of the same strain as the reference. For these Urabe mumps vaccines the variation in relative potency was around 1.5 log10.

The 1st International Standard for anti-measles serum.

The 1st International Standard for anti-measles serum has been established on the basis of a collaborative study. There were four participating laboratories in four countries and three types of assay used. This standard has been assigned a potency of 5 IU anti-measles antibody per ampoule.

A collaborative study to assess the proficiency of laboratory estimates of potency of live measles vaccines.

A collaborative study was undertaken to assess the variability in estimates of the potency of measles vaccines. Overall a median variation of 2.0 log10 between estimates was observed. This was reduced to a median of 1.0 log10 when the potencies were expressed relative to a reference vaccine. A difference in the sensitivity between plaque assays and TCID50 assays was also reduced when relative potencies were used. The benefit of including a common reference preparation in vaccine assays was therefore demonstrated. For the vaccines assayed in this study, it was not necessary to use a measles reference of the same strain as the vaccines tested. We therefore recommend that measles vaccines be assayed against a single international reference preparation.

Comparison of the nucleotide sequence of the SH gene and flanking regions of mumps vaccine virus (Urabe strain) grown on different substrates and isolated from vaccinees.

The small hydrophobic (SH) protein gene and flanking regions of the Urabe Am9 vaccine strain of mumps virus were amplified by the polymerase chain reaction and sequenced directly by the dideoxynucleotide chain termination method. The 434 bp sequence was identical for the Urabe strain isolated from vaccines produced by three manufacturers and for virus isolated following post-vaccination parotitis. No changes were detected for coding, non-coding or intergenic regions between virus grown on different substrates. The Urabe virus SH coding region differed from the published sequence for strain SBL-1 by 14.4% at the nucleotide level and 24.6% at the amino acid level. The 5' non-coding SH region was strongly conserved between the two strains (2% different), whereas the other non-coding regions were not.