Adenoviruses from human immunodeficiency virus-infected individuals, including two strains that represent new candidate serotypes Ad50 and Ad51 of species B1 and D, respectively.

Adenovirus (Ad) isolates from a large number of human immunodeficiency virus (HIV)-infected individuals were compared serologically and genetically with Ad isolates from immunocompetent patients. Between 1982 and 1994, stool and urine samples from 137 subjects with AIDS hospitalized in The Netherlands yielded 143 Ad strains. Forty additional Ad strains were obtained from 35 HIV-positive patients in Manchester, United Kingdom, in 1992 and 1993. Of these 183 HIV-associated Ad strains, 84% belonged to species D and 3% belonged to species C. These strains were compared with 2,301 Ad strains collected during general diagnostic examinations in The Netherlands from 1973 to 1992. Of the latter strains, 5% belonged to species D and 49% belonged to species C. Two of the Ads isolated from fecal specimens of AIDS patients represent new serotypes: candidate Ad serotype 50 (prototype strain, Wan) of subspecies B1 and candidate Ad serotype 51 (prototype strain, Bom) of species D. The DNA restriction enzyme patterns of strains Wan and Bom differed from the patterns of all established prototypes.

Adenovirus types 2, 8, and 37 associated with genital infections in patients attending a sexually transmitted disease clinic.

Adenoviruses (Ads) are an important cause of respiratory illness, conjunctivitis, and gastroenteritis, but they are seldom recognized as a potential cause of sexually transmitted disease. We performed virus cultures on approximately 7,000 patients attending a sexually transmitted disease clinic or other health department clinics for the evaluation of genital ulcers, urethritis, or conjunctivitis. Ads were isolated from genital or conjunctival specimens obtained from 23 (0.33%) patients. Among the 20 Ad-positive men, 15 (75%) had urethritis, 12 (60%) had conjunctivitis, and 10 (50%) had both. All three Ad-positive women had vaginal discharge and genital ulcers or fissures. Ad isolates from 17 patients were available for serotyping. Ad type 37 was isolated from 14 patients, Ad type 8 was isolated from 2 patients, and Ad type 2 was isolated from 1 patient. In three of the Ad type 37 cases, Ad was recovered from both urethral and conjunctival specimens. One of the Ad type 8 cases had conjunctivitis, but the Ad type 2 case did not. Ads, particularly type 37, may be a sexually transmissible cause of genital ulcers, urethritis, and conjunctivitis.

Comparison of monoclonal biotin-avidin enzyme immunoassay and monoclonal time-resolved fluoroimmunoassay in detection of respiratory virus antigens.

BACKGROUND: Detection of respiratory viruses by time-resolved fluoroimmunoassay based on monoclonal antibodies were developed in our laboratories in the late 1980s and they have been successfully used in daily diagnosis for more than seven years. Later, similar Biotin-EIAs were developed but the sensitivities were unsatisfactory. OBJECTIVES: Further optimization of monoclonal Biotin-EIAs and comparison of the optimized assays with TR-FIAs. STUDY DESIGN: Variations in test format, diluents, incubation times and temperatures, and different monoclonal antibodies were tested, and the final comparisons were made with TR-FIA using stored nasopharyngeal aspirates. RESULTS: The improvements in Biotin-EIA featured four changes which increased sensitivity in the assay: (a) test diluent contained diethylenetriamino-pentaacetic acid; (b) antigen and biotinylated detector antibody were added simultaneously; (c) reaction time was extended from 1 h at 37 degrees C to overnight at 4 degrees C; (d) from the thirteen monoclonal antibodies used in TR-FIA, ten were optimal also in Biotin-EIA, but in the parainfluenza 1 and 2 assays other monoclonals proved more sensitive. Out of 257 originally positive specimens tested in the comparison studies, 192 (74.7%) were again positive and 54 (21.0%) were negative in both assays; nine were negative in TR-FIA but positive in Biotin-EIA, while two specimens were negative in Biotin-EIA but positive in TR-FIA. The overall agreement between the two assays was 95.7%. CONCLUSIONS: All monoclonal Biotin-EIAs can be optimized to the same sensitivity as TR-FIAs for the detection of respiratory viruses. Laboratories which have no TR-FIA expertise may use Biotin-EIA in the diagnosis of acute respiratory infections.

Neonatal pulmonary insufficiency caused by adenovirus infection successfully treated with extracorporeal membrane oxygenation.

Two infants with fulminant early-onset sepsis syndrome and respiratory failure are described. Adenovirus was isolated from cultures from both patients. Complications during pregnancy and respiratory failure that required tracheal intubation at birth suggested congenital infection. Both infants were successfully treated with extracorporeal membrane oxygenation.

Antigen detection in human respiratory Coronavirus infections by monoclonal time-resolved fluoroimmunoassay.

BACKGROUND: The diagnosis of respiratory infections by detecting viral antigens has received considerable attention using immunofluorescent assays (IFA) and enzyme immunoassays (EIA). Time-resolved fluoroimmunoassay (TR-FIA) has been developed for several viruses. OBJECTIVES: To prepare monoclonal antibodies to coronavirus strains, to incorporate them into a TR-FIA, and test the assay on clinical specimens. STUDY DESIGN: Monoclonal antibodies were prepared to the N nucleoprotein of the two human respiratory coronaviruses, HCV strains 229E and OC43. Monoclonals to both viruses were completely type-specific; they did not cross-react between themselves or with multiple strains of other respiratory viruses. These antibodies were configured into optimized EIA and TR-FIA tests. The all-monoclonal tests were then compared to polyclonal EIA tests in terms of their ability to detect virus in clinical specimens. RESULTS: The all-monoclonal TR-FIA was uniformly the most sensitive, detecting virus in all 13 229E-positive specimens compared to 69% for the monoclonal EIA and 54% for the polyclonal EIA test. Similar results were obtained for 10 OC43-positive specimens: 100% in TR-FIA, 90% in monoclonal EIA, and 80% in polyclonal EIA. For 229E in TR-FIA, mean positive/negative (P/N) ratios were 143 for 229E-positive human embryonic lung fibroblast (HLF) cell culture fluids and 10 for positive nasopharyngeal aspirate specimens; for OC43 in TR-FIA, mean P/N values were 964 for OC43-positive rhabdomyosarcoma (RD) cell culture fluids and 174 for positive NPA specimens. The sensitivities of the TR-FIA were determined with purified virions to be 0.308 ng virus per well for HCV-229E and 0.098 ng virus per well for HCV-OC43. CONCLUSIONS: This rapid and sensitive test appears to be much more sensitive than traditional antigen detection assays but will require more extensive field testing on clinical specimens.

Subgrouping of respiratory syncytial virus strains from Australia and Papua New Guinea by biological and antigenic characteristics.

Strains of respiratory syncytial virus from 3 major areas of Australia and Papua New Guinea (PNG) were analyzed for variations in their antigenic and biological properties and in the molecular weights of their major structural proteins. Seventy-eight strains from infants and young children with LRI were collected from 1981-1984. The RSV season in the Australian cities lasted from April through September, with major peaks in July of each year, while the RSV season in tropical PNG was year-round, with small peaks in March and October of each year coinciding with excessive rainfall. Fifty-six strains were analyzed in detail; 40 were typed by time-resolved fluoroimmunoassay with monoclonal antibodies as group A strains and 16 were group B; both groups were concurrent. Three children of one family had sequential RSV infections 13 months apart, and the etiologic group A strain was identical both years in terms of growth and antigenic properties with strain-specific ferret antisera; the second infection was milder in all three children. On average, the group A strains replicated considerably better than group B strains in HEp2 cells, producing 53% more syncytia and 99% higher infectious virus titers in 31% less time in culture. Ten group A and B reference strains exhibited the same growth patterns as the A and B regional strains, respectively. Differences in antigenicity as measured with hyperimmune antisera to prototype Long strain were even greater. Group A strains exhibited a mean 68% greater IFA staining than B strains, a 71% greater EIA reaction, and were neutralized to 69% higher serum titers than B strains. Again, the reference A and B strains included as controls gave patterns identical to those of the regional strains. Finally, the P phosphoprotein had consistently higher molecular weight in A strains (mean 35,900) than B strains (mean 33,100). Small variations in the sizes of the F and G glycoproteins were not sufficient to suggest grouping on this basis.

Sequence and functional analysis of the human adenovirus type 7 E3-gp19K protein from 17 clinical isolates.

The adenovirus (Ad) early region 3 (E3) glycoprotein of 19K (gp19K) binds major histocompatibility (MHC) class I antigens in the endoplasmic reticulum (ER), and the gp19K-class I complex is retained in the ER through an ER retention signal at the C-terminus of gp19K. This retention of class I antigens blocks cytolysis of gp19K-expressing cells by cytotoxic T lymphocytes (CTL). Animal models infected with Ad mutants lacking gp19K support a role for gp19K in counteracting a CTL response. Gp19K binds with different avidities to different class I antigens, and portions of the gp19K sequence are highly variable among Ad serotypes in different subgroups (Ad3, 11, and Ad35 in subgroup B; Ad2 and Ad5 in subgroup C); this raises the possibility that certain human individuals may be more susceptible to productive or persistent infection by particular serotypes of Ad, depending on the haplotype of the individual and the type of Ad. To begin to address this possibility, the gp19K gene from 17 very diverse Ad7 (subgroup B) clinical isolates was amplified by the polymerase chain reaction, and the DNA sequences were determined. The Ad7 gp19K sequence was 98% identical to that of Ad3. Surprisingly, we found complete conservation of the amino acid sequence of gp19K from all but one of the clinical isolates; one isolate had a conservative Ala to Val substitution. Gp19K from Ad7 clinical isolates representing distinct Ad7 genotypes co-immunoprecipitated with class I antigens. Our data indicate that there is very strong evolutionary pressure to maintain the sequence of gp19K in Ad7. The only known function for gp19K from different Ad serotypes is binding to class I antigens. It is interesting to consider, therefore, what selective pressure operates to maintain the sequence of gp19K among serotypes within a subgroup, and yet allows for very significant divergence in the sequence of gp19K among serotypes in different subgroups. The possible role of MHC class I antigens in this selection process is discussed.

Epidemic keratoconjunctivitis in a chronic care facility: risk factors and measures for control.

OBJECTIVE: To study patterns of transmission of epidemic keratoconjunctivitis (EKC) in a chronic care facility and to assess control measures and prevent future outbreaks in this setting. DESIGN: A retrospective cohort study. SETTING: A 120-bed, four-unit, skilled nursing facility. PATIENTS: Residents and employees of the above facility. INTERVENTIONS: Increased frequency of cleaning; use of bleach disinfectant; universal precautions in handling eye secretions from residents with conjunctivitis; cohorting residents by unit; suspension of new admissions; closure of common gathering areas. MEASUREMENTS: Resident demographics; possible risk factors for infection among residents (including mobility, underlying illness, medications, involvement in social activity, level of confusion) and among employees (including co-morbid illnesses and eye conditions, exposures to persons with conjunctivitis, visits to eye care specialists, use of contact lenses or glasses); testing of conjunctival specimens from symptomatic persons for viral and bacterial agents. RESULTS: Of 95 residents on three chronic care units, 47 (attack rate 49%) had onset of eye symptoms consistent with EKC between September 14 and December 7, 1990. Thirty-eight (81%) of these had onset following the onset of symptoms in a resident with dementia who, despite habitual eye-rubbing and wandering into other residents' rooms, was not isolated or restricted in any way. Attack rates were higher (though not statistically significant) among more mobile residents (60% for ambulatory residents) and among those considered by staff to be confused (56%). Rapid antigen detection and culture confirmed adenovirus type 37 as the etiologic agent. CONCLUSIONS: Transmission of infection with adenovirus type 37 was successfully interrupted following strict infection control, suspension of new admissions, cohorting of residents by unit, and change to a disinfectant that inactivates adenovirus. Recognition of conjunctivitis as an appropriate reason for restricting movement of an infected resident may have prevented extensive viral transmission in this outbreak.

Detection of adenovirus in clinical specimens by polymerase chain reaction and liquid-phase hybridization quantitated by time-resolved fluorometry.

In addition to tests for the group-specific hexon antigen of adenoviruses, adenoviruses can be detected in clinical specimens by hybridization assays utilizing the widely shared base sequences of the region of the hexon gene that codes for the group-reactive determinants. We have developed a liquid-phase hybridization system with biotin- and europium-labeled probes which are reacted after DNA amplification of a 161-bp region of the hexon gene and which are quantitated by time-resolved (TR) fluorometry in streptavidin-coated microtiter wells. Polymerase chain reaction (PCR)-TR fluorometry is not a rapid test in the usual sense, but it is highly useful for specimens with inherent toxicity or with low virus yield, such as organ minces and specimens obtained late in the course of an illness. In a survey of 103 specimens tested by this method, including urine, stool, and tissue suspensions, the agreement with the hexon-specific TR fluoroimmunoassay antigen test for positive specimens was 100% and the sensitivity compared with that of virus culture was 91%. The PCR-TR fluorometry system was also shown to be advantageous as a quantitative measure of PCR products.

Sensitivity of NCI-H292 human lung mucoepidermoid cells for respiratory and other human viruses.

NCI-H292 mucoepidermoid carcinoma cells from human lungs were shown in an earlier report to be a fully adequate substitute for primary rhesus monkey kidney (MK) cells for the isolation and propagation of the human paramyxoviruses. Although sensitivity for ortho- and paramyxoviruses was the principal reason for using MK cells, the cells were also sensitive to many other viruses, which constituted another important value of MK cells. That MK cells supported the initial isolation and growth of so many respiratory viruses made it a mandatory cell type for any clinical laboratory. We therefore felt it was imperative to evaluate the virus spectrum of NCI-H292 cells, which are being used as a substitute for MK cells in many laboratories. In the present report, we show that NCI-H292 cells are sensitive for vaccinia virus, herpes simplex virus, adenoviruses, BK polyomavirus, reoviruses, measles virus, respiratory syncytial virus, some strains of influenza virus type A, most enteroviruses, and rhinoviruses, in addition to the parainfluenza and mumps viruses originally reported. Furthermore, these viruses replicate in NCI-H292 cells to the same virus and antigen titers and at the same speed of replication as they do in their usually preferred cells. The NCI-H292 cells are therefore an excellent substitute for MK cells in terms of laboratory safety, ease of availability, paramyxovirus isolation, and broad virus spectrum but cannot substitute for MK cells for the isolation of influenza viruses.

Isolation of parainfluenza virus type 3 from cerebrospinal fluid associated with aseptic meningitis.

Parainfluenza virus type 3 has been isolated from the cerebral spinal fluid (CSF) from six individuals--four children and two adults--over a 10-year period. All had fever, and four had signs of meningitis. All recovered uneventfully, including one child undergoing chemotherapy for medulloblastoma. The clinical presentation of this child who developed parainfluenza virus type 3 meningitis is described, and the cases of five other individuals with parainfluenza virus type 3 isolated from the CSF are briefly reviewed. The paramyxovirus parainfluenza type 3, in addition to mumps virus, may be considered capable of infecting the central nervous system.

Characterization of two divergent adenovirus 31 strains.

Two divergent strains of adenovirus type 31 were analyzed by neutralization test and restriction endonuclease (RE) patterns in an effort to find the basis for their genetic variability. One strain, isolated from the throat of a child in Maryland during an upper respiratory illness in 1968, was partially neutralized by Ad 31 antisera (to 16-fold lower than homologous titer) while its own antiserum fully neutralized prototype Ad 31 virus, but shared only 9% of comigrating RE fragments with Ad 31 prototype (vs. 30% with Ad 18 prototype); however, PCR tests specific for the inverted terminal repeat (ITR) sequence of Ads 12 and 18 were negative. The other strain, recovered from a stool sample from an infant with diarrhea in Georgia in 1979, was inhibited by Ad 31 antiserum to within 4-fold homologous titer, but shared only 15% of comigrating fragments with Ad 31 prototype (vs. 91% with Ad 18 prototype); ITR-specific PCR tests with this virus were positive for Ad 12/Ad 18. These data suggest that both strains are from separate evolutionary lines of Ad 31 unrelated to all other isolates studied to date by RE analysis, and that the partial neutralization by prototype Ad 31 antisera might represent small mutations in the hexon gene.

Time-resolved fluoroimmunoassays with monoclonal antibodies for rapid identification of parainfluenza type 4 and mumps viruses.

Monoclonal antibodies were prepared to the F and M proteins of parainfluenza 4A and 4B and to mumpsvirus to obtain reagents that could be configured into type-specific yet broadly-reactive IFA, EIA, and TR-FIA tests. Several antibodies to parainfluenza 4A also detected subtype 4B, although to a somewhat lower signal, and thus were well suited to generic parainfluenza type 4 tests that were comparable to similar tests previously described for parainfluenza types 1, 2, and 3. Monoclonals to subtype 4B were less able to detect 4A because of high background problems in one or another test. Monoclonals to mumpsvirus F protein were completely type-specific. These antibodies were screened by IFA and EIA for broad reactivity with diverse strains of each virus and were configured into optimized EIA and TR-FIA tests. The all-monoclonal tests were then compared to polyclonal tests in terms of their ability to detect virus in clinical specimens. The all-monoclonal TR-FIA was uniformly the most sensitive, detecting virus in 80% of culture-positive parainfluenza 4A specimens, 67% of parainfluenza 4B specimens, and 90% of mumps specimens, compared to 40-67% for the monoclonal EIA tests and 33-60% for the polyclonal EIA tests. For parainfluenza 4 TR-FIA, mean P/N values were 379 for subtype 4A cell culture fluids (228 for subtype 4B cultures) and 57 for 4A clinical specimens (43 for 4B specimens). For mumpsvirus TR-FIA, mean P/N values were 27 for culture fluids and 32 for clinical specimens. The sensitivities of the TR-FIA were determined with purified virus to be 0.28 ng virus per well for parainfluenza 4A and 0.70 ng virus per well for mumpsvirus.

Viral susceptibility of an immortalized human microvascular endothelial cell line.

CDC/EU.HMEC-1 is the first immortalized human microvascular endothelial cell line that retains morphologic, phenotypic, and functional characteristics of a normal human microvascular endothelial cell. This study evaluates a variety of viruses and their effects on this human endothelial cell line. The data indicate that adenoviruses, some herpesviruses, reoviruses and most picornaviruses grow well in HMEC-1, with distinctive cytopathic effects. The paramyxoviruses, however, do not appear to propagate, nor does HIV. The findings indicate that microvascular endothelial cells may act as a reservoir of these viruses; it also suggests the possibility that microvascular endothelium could be involved in the processing and presentation of antigen to immune cells.

Restriction endonuclease patterns of adenovirus type 12 and 18.

Restriction endonuclease analysis using 10 restriction enzymes was performed on six and three wild isolates of adenovirus (Ad) type 12 and 18, respectively. Among the Ad12 strains, five DNA variants could be identified. The degree of pairwise comigration of restriction fragments suggests a high degree of genomic diversity within Ad12. The wild isolates of Ad18, on the other hand, displayed a low degree of genetic variability and comprised one DNA variant closely related to the prototype strain. The BglII, BstEII, and HindIII restriction endonuclease patterns of Ad18 were inconsistent with those originally presented. Identical RE-patterns among Ad18 prototype strains (DC) obtained from four different sources, including directly from the American Type Culture Collection, verify that the genuine Ad18 prototype was used in the present study. Using the revised restriction patterns of BglII, BstEII, and HindIII, a proper identification of Ad18 will be facilitated.

Adenoviruses in the immunocompromised host.

Adenoviruses are among the many pathogens and opportunistic agents that cause serious infection in the congenitally immunocompromised, in patients undergoing immunosuppressive treatment for organ and tissue transplants and for cancers, and in human immunodeficiency virus-infected patients. Adenovirus infections in these patients tend to become disseminated and severe, and the serotypes involved are clustered according to the age of the patient and the nature of the immunosuppression. Over 300 adenovirus infections in immunocompromised patients, with an overall case fatality rate of 48%, are reviewed in this paper. Children with severe combined immunodeficiency syndrome and other primary immunodeficiencies are exposed to the serotypes of subgroups B and C that commonly infect young children, and thus their infections are due to types 1 to 7 and 31 of subgenus A. Children with bone marrow and liver transplants often have lung and liver adenovirus infections that are due to an expanded set of subgenus A, B, C, and E serotypes. Adults with kidney transplants have viruses of subgenus B, mostly types 11, 34, and 35, which cause cystitis. This review indicates that 11% of transplant recipients become infected with adenoviruses, with case fatality rates from 60% for bone marrow transplant patients to 18% for renal transplant patients. Patients with AIDS become infected with a diversity of serotypes of all subgenera because their adult age and life-style expose them to many adenoviruses, possibly resulting in antigenically intermediate strains that are not found elsewhere. Interestingly, isolates from the urine of AIDS patients are generally of subgenus B and comprise types 11, 21, 34, 35, and intermediate strains of these types, whereas isolates from stool are of subgenus D and comprise many rare, new, and intermediate strains that are untypeable for practical purposes. It has been estimated that adenoviruses cause active infection in 12% of AIDS patients and that 45% of these infections terminate in death within 2 months. In all immunocompromised patients, generalized illness involving the central nervous system, respiratory system, hepatitis, and gastroenteritis usually have a fulminant course and result in death. Treatments for adenovirus infections are of little proven value, although certain purine and pyrimidine analogs have shown beneficial effects in vitro and may be promising drugs.

Astrovirus and adenovirus associated with diarrhea in children in day care settings.

The relative importance of astrovirus and adenoviruses as etiologic agents of diarrhea among children in day care was examined. Stool specimens from this prospective study were screened for both astrovirus and adenovirus hexon with two new indirect double-antibody assays and for enteric adenoviruses with an EIA specific for serotypes 40 and 41. Astrovirus was detected in a significantly greater percentage of children with diarrhea (4%, 21/524) than of those without (less than 1%, 1/138) (P less than .05); however, no difference between such such children with adenovirus infections was found (8%, 43/565, and 8%, 10/129, respectively). Overall, 30% (13/43) of all adenovirus hexon-positive specimens were enteric serotypes, and by extrapolation, enteric adenoviruses were identified in an equal percentage of children (2%) with and without diarrhea. This study documents the presence of astrovirus and enteric adenoviruses among children in day care in the United States, associates astrovirus with diarrhea in this setting, and suggests that viral agents may be the most common enteric pathogens among children with diarrhea in day care.

Genome analysis of adenovirus type 31 strains from immunocompromised and immunocompetent patients.

Adenovirus type 31 (Ad31) was isolated from 15 immunocompromised patients in 12 of whom seroconversion was also recorded. Ad31 infection has a substantial clinical relevance since 8 of 10 with lower respiratory tract infection and 4 of 4 with hepatitis died. Therefore, Ad31 isolates from immunocompetent and immunodeficient hosts were compared by restriction endonuclease analysis. Nine genome types were identified among the 79 Ad31 isolates. Pairwise comparison of comigrating restriction fragments indicated that the genome types could be divided into three genomic clusters. Several Ad31 genome types were isolated from immunocompromised patients, but no highly virulent genome type could be found. A genome type was identified in a child with severe combined immunodeficiency who originally was infected with another genome type. This observation is suggested to have evolutionary implications.

Antigenic relationships among the 47 human adenoviruses determined in reference horse antisera.

Reference equine antisera to all 47 serotypes of human adenoviruses presently described have been prepared and evaluated by reciprocal neutralization and hemagglutination-inhibition tests. All tests were carried to endpoint dilutions a minimum of five times in each direction to give accurate values for homologous and heterologous antibody titers. Significant cross-reactions in the horse antisera were compared to similar data obtained from rabbit antisera. Using this analysis, major antigenic relationships exist among types 12-18-31 of subgenus A, types 7-11-14 and 34-35 of subgenus B, types 8-9-10, 10-19-37, 13-38-39, 15-22-42, 20-47, 24-32-33-46, and 29-45 of subgenus D, types 16-4 between subgenera B and E, and types 40-41 of subgenus F. Across all subgenera, types 8, 10, 13, 15, 17, 19, 26, 29, 39, 40, and 43 have antigenic moieties found most frequently in other types, averaging 12 heterologous reactions per type when summing both tests in both directions. Types 20, 30, 32, and 45 exhibit shared determinants slightly less often, with a mean of 8 heterologous reactions per type.

NCI-H292 as an alternative cell line for the isolation and propagation of the human paramyxoviruses.

Primary rhesus monkey kidney (MK) cells have long been the cells of choice for isolation and propagation of the human paramyxoviruses (parainfluenza 1, 2, 3, 4A, 4B, and mumps). However, problems with the supply and cost of MK cells and the presence of endogenous viruses, including herpes B virus and SV-5, necessitated a search for an alternative cell line. Continuous cell cultures of human origin (L132, A-549, HuT-292, HEK, G-293, G-401, A-498, A-704, CAKI-1, RD) and simian origin (LLC-MK2, BSC-1, MA-104, Vero) were evaluated for their capacity to support the growth of the human paramyxoviruses, as followed by cytopathic effect, hemadsorption, hemagglutination, and EIA. NCI-H292 (HuT-292) human lung mucoepidermoid carcinoma cells (ATCC # CRL-1848) proved to be the most sensitive line for cultivating all serotypes and strains of the paramyxoviruses. These cells were also shown to be a suitable substitute for MK in primary isolation of paramyxoviruses from clinical specimens. RPMI-1640 with 1.5 micrograms/ml trypsin was the preferred maintenance medium; alternatively, Eagle's MEM supplemented with 1.5 micrograms/ml trypsin and 0.1% ITS was satisfactory. NCI-H292 cells are a continuous line with excellent growth characteristics, although the genetic polyploidy of the cells may limit the number of passages of usable cells.