Rapid diagnosis of measles from urinary sediments stained with fluorescent antibody

The Host Cell Receptors for Measles Virus and Their Interaction with the Viral Hemagglutinin (H) Protein

The hemagglutinin (H) protein of measles virus (MeV) interacts with a cellular receptor which constitutes the initial stage of infection. Binding of H to this host cell receptor subsequently triggers the F protein to activate fusion between virus and host plasma membranes. The search for MeV receptors began with vaccine/laboratory virus strains and evolved to more relevant receptors used by wild-type MeV. Vaccine or laboratory strains of measles virus have been adapted to grow in common cell lines such as Vero and HeLa cells, and were found to use membrane cofactor protein (CD46) as a receptor. CD46 is a regulator that normally prevents cells from complement-mediated self-destruction, and is found on the surface of all human cells, with the exception of erythrocytes. Mutations in the H protein, which occur during adaptation and allow the virus to use CD46 as a receptor, have been identified. Wild-type isolates of measles virus cannot use the CD46 receptor. However, both vaccine/laboratory and wild-type strains can use an immune cell receptor called signaling lymphocyte activation molecule family member 1 (SLAMF1; also called CD150) and a recently discovered epithelial receptor known as Nectin-4. SLAMF1 is found on activated B, T, dendritic, and monocyte cells, and is the initial target for infections by measles virus. Nectin-4 is an adherens junction protein found at the basal surfaces of many polarized epithelial cells, including those of the airways. It is also over-expressed on the apical and basal surfaces of many adenocarcinomas, and is a cancer marker for metastasis and tumor survival. Nectin-4 is a secondary exit receptor which allows measles virus to replicate and amplify in the airways, where the virus is expelled from the body in aerosol droplets. The amino acid residues of H protein that are involved in binding to each of the receptors have been identified through X-ray crystallography and site-specific mutagenesis. Recombinant measles “blind” to each of these receptors have been constructed, allowing the virus to selectively infect receptor specific cell lines. Finally, the observations that SLAMF1 is found on lymphomas and that Nectin-4 is expressed on the cell surfaces of many adenocarcinomas highlight the potential of measles virus for oncolytic therapy. Although CD46 is also upregulated on many tumors, it is less useful as a target for cancer therapy, since normal human cells express this protein on their surfaces.

Case of vaccine-associated measles five weeks post-immunisation, British Columbia, Canada, October 2013

We describe a case of vaccine-associated measles in a two-year-old patient from British Columbia, Canada, in October 2013, who received her first dose of measles-containing vaccine 37 days prior to onset of prodromal symptoms. Identification of this delayed vaccine-associated case occurred in the context of an outbreak investigation of a measles cluster.

A human lung carcinoma cell line supports efficient measles virus growth and syncytium formation via a SLAM- and CD46-independent mechanism

Measles virus (MV) propagates mainly in lymphoid organs throughout the body and produces syncytia by using signaling lymphocyte activation molecule (SLAM) as a receptor. MV also spreads in SLAM-negative epithelial tissues by unknown mechanisms. Ubiquitously expressed CD46 functions as another receptor for vaccine strains of MV but not for wild-type strains. We here show that MV grows and produces syncytia efficiently in a human lung adenocarcinoma cell line via a SLAM- and CD46-independent mechanism using a novel receptor-binding site on the hemagglutinin protein. This infection model could advance our understanding of MV infection of SLAM-negative epithelial cells and tissues.

A rapid culture assay for examining measles virus infections from urine specimens

BACKGROUND

Large numbers of measles virus (MV) specimens are processed in our laboratory each year as part of a molecular epidemiological study of MV in South Africa. The development of a sensitive, rapid virus isolation system is needed to cope with the number of specimens processed.

OBJECTIVES

A comparison was made of centrifugation-enhanced shell vial culture and standard tissue culture using B95a cells for the isolation of MV from throat swabs and urine.

STUDY DESIGN

The rapid method was initially evaluated using Schwarz vaccine virus and then compared to standard culture using throat swab specimens.

RESULTS

The shell via assay proved to be ten times more sensitive than standard culture in the initial evaluation. Of 43 throat swab specimens, 37 (86%) were positive and 6 (14%) negative in standard culture using B95a cells. The specimens were removed after adsorption in standard culture, frozen and then used in the shell vial assay. It was found that 16/27 were positive in the shell vial assay (24 of these 27 being positive in standard culture,) and 8 negative and 8 specimens gave an indeterminate result. For the 45 urine specimens used in the shell vial assay, 71% were positive, 11% negative and 18% gave an indeterminate result, due to too few cells being present for antigen determination by indirect fluorescent antibody assay. Results were obtained in 4 days, as opposed to the average of 14 days for confirmed isolation in standard culture.

CONCLUSION

Rapid culture substantially reduced total test time, was less labour-intensive and was as sensitive as standard culture for the isolation of measles virus from clinical specimens.

Markedly elevated levels of β2-microglobulin in urine with measles viruria in patients with measles

BACKGROUND

Measles is a highly contagious infectious disease in children. However, the pathogenesis has not yet been fully defined since susceptible cells to measles virus (MV) had not been developed. Recently, B95a cells, which are very susceptible to MV, have been reported.

OBJECTIVES

To evaluate measles viruria in patients with measles, isolation of MV from urine was performed using B95a cells.

STUDY DESIGN

Isolation of MV from supernates or sediments of urine in patients with measles was performed using B95a cells. The levels of beta2-microglobulin (MG) in urine and serum were also measured.

RESULTS

MV was isolated from either supernates or sediments of urine. MV was isolated from 10 of 11 samples (91%) within 2 days of the appearance of a rash. MV was isolated from supernates of urine for up to 4 days after the appearance of a rash, and from sediments for up to 5 days. The levels of urinary beta2-MG were elevated within 2 days of the appearance of a rash. The levels of urinary beta2-MG with measles viruria were significantly higher compared to those without measles viruria.

CONCLUSIONS

Measles viruria may occur early in all patients with measles and elevated levels of urinary beta2-MG in patients with measles may be the consequence of tubular injury.

Detection of measles virus RNA in urine specimens from vaccine recipients

Analysis of urine specimens by using reverse transcriptase-PCR was evaluated as a rapid assay to identify individuals infected with measles virus. For the study, daily urine samples were obtained from either 15-month-old children or young adults following measles immunization. Overall, measles virus RNA was detected in 10 of 12 children during the 2-week sampling period. In some cases, measles virus RNA was detected as early as 1 day or as late as 14 days after vaccination. Measles virus RNA was also detected in the urine samples from all four of the young adults between 1 and 13 days after vaccination. This assay will enable continued studies of the shedding and transmission of measles virus and, it is hoped, will provide a rapid means to identify measles infection, especially in mild or asymptomatic cases.

Use of immunofluorescence to identify measles virus infections

Monoclonal antibody to measles virus was used successfully to identify measles virus antigen directly in clinical specimens, as well as in cell cultures. Pooled nasopharyngeal-throat swab specimens had a higher yield than throat swabs or urine samples for virus detection. Use of A549 cell cultures in the spin amplification vial assay proved to be highly efficient, allowing virus recognition within 1 to 2 days of inoculation. A combination of appropriately collected specimens, which includes a nasopharyngeal-throat swab, direct antigen detection with monoclonal antibody to measles in an indirect immunofluorescence system, and the spin amplification vial assay using A549 cells provides a sensitive and rapid system for isolation and/or identification of measles virus infections.

Acute infectious erythemas in children: a clinico-microbiological study

One-hundred children with an acute illness comprising fever and widespread erythematous rash were prospectively studied to determine whether clinical presentations are helpful in defining the causative agent and to identify the most appropriate microbiological specimens. An infectious agent was identified in 65 children; 72% were viruses, 20% were bacteria, 5% were Mycoplasma pneumoniae and in 3% both viruses and bacteria were detected. The most common infectious agents were picornaviruses, an atypical presentation of measles and Group A beta-haemolytic Streptococcus. Different patterns of rash occurred with each of these infections. The clinical presentation of a child with an acute febrile illness and rash was unhelpful in defining the causative agent. Routine management should include a throat swab for bacterial investigation and in selected cases a blood sample for IgM viral titres.

Postmortem detection of measles virus in non-neural tissues in subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis, a rare, progressive, fatal central nervous system disease of children, is caused by measles virus. Clinical signs occur months to several years after recovery from acute measles infection. It is not known where the virus persists while the disease is inapparent. Involvement of organs outside the central nervous system has rarely been documented. To search for possible peripheral reservoirs of measles virus we used in situ hybridization to probe for measles virus RNA and immunocytochemical studies to localize measles virus antigens ina variety of organs taken at autopsy from confirmed cases of subacute sclerosing panencephalitis. Seven of 9 cadavers were found to contain measles virus RNA or antigens, or both, in at least one location outside the central nervous system. These sites included lymphoid organs such as thymus, spleen, lymph nodes, and tonsil, suggesting a role for lymphocytes in disease pathogenesis. Virus was also detected in kidney, lung, and glandular tissues such as pancreas, adrenal, and pituitary. These reservoirs may provide the antigenic stimulus leading to the elevated response characteristic for subacute sclerosing panencephalitis.

A fourteen-year study to identify measles antigen in urine specimens by fluorescent-antibody methods

Between 1965 and 1979 inclusive, 426 morning urine specimens from 410 patients admitted to hospital with the provisional diagnosis of measles were tested for measles antigen by fluorescent-antibody methods. One hundred and forty-two specimens (33.3 per cent) were positive. Of 74 patients who were clinically assessed not to have measles, 6/77 specimens (7.8 per cent) gave false positive results, and 71/77 (92.2 per cent) gave true negative results. Three hundred and forty-nine urine specimens were tested from 336 patients clinically judged to have had measles and 136 of these specimens (39 per cent) were positive. The positive rate was highest in a small number of specimens taken before the rash and next highest at the onset of the rash. The positive rate then fell; it rose again near the end of the first week, but the further increased positive rate after that time was associated with very small numbers of specimens. Of 12 child contacts of measles, 5/12 (41.67 per cent) had positive urine specimens and one of them developed measles two days after sampling. None of the seven patients with negative urine specimens developed measles. Measles antigen was detected in urine sediment by fluorescent-antibody tests in 39 per cent of the patients with measles studied.

Application of immunofluorescence to a study of measles

A new and rapid method for the laboratory diagnosis of measles, using the fluorescent antibody technique applied to nasopharyngeal secretions is described. The reliability of the method was best shown by correlation with clinical diagnosis, which gave an overall agreement of 95% in 53 cases of typical clinical measles and 72 control children. Correlation with results of tissue culture and serology was also good, though these methods are in practice too infrequently successful to be used as the main standards of reliability. The antiserum used for immunoflorescence showed no cross-reactivity with other viruses. Viruses could be identified by the fluorescent antibody technique from 4 days before to 10 days after the onset of the rash in a high proportion of cases. The wider applications of this method include rapid diagnosis of measles before the rash has appeared; in cases where clinical diagnosis is in doubt, especially in dark-skinned children, or when the illness has been modified by previous vaccination; prevention of cross-infection by early detection of measles; and investigation of the immune response and its relationship to nutritional status.

Pathology of measles in rhesus monkeys

Skin biopsies were taken from 16 monkeys with measles rash. Histopathological changes consisted of multinucleated epithelial giant cells in the epidermis and hair follicles, proliferative and degenerative changes of the epidermis, and mild inflammation of the dermis. Necropsies were performed on two monkeys with a typical rash and on 26 additional monkeys that died during outbreaks in the colony. Lesions attributable to rubeola virus were found in the respiratory system, lymphoid system, gastrointestinal tract, salivary glands, thyroid gland, liver, pancreas, and urinary system. In these organs the finding that was characteristic of measles was the presence of syncytial giant cells, some of which contained both intranuclear and cytoplasmic inclusions. The significance of syncytia and the mechanism of their formation are discussed.

Nephropathy and viroses

The kidneys often are involved during viral diseases, but seem to be peculiarly resistant to injury in contrast to other organs and tissues. They rarely bear the brunt of infection. Clinical evidence of viral nephritis or nephrosis seldom is of serious import and when it occurs it may be indistinguishable from that of other cause unless specific diagnostic criteria are fulfilled. With increasing interest in the subject, as happens in other circumstances, more evidence of acute or chronic viral injury to the kidneys no doubt will accrue.

Viral infections associated with renal disturbance

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