Cross-antigenicity among EV71 strains from different genogroups isolated in Yamagata, Japan, between 1990 and 2007.

We isolated and identified six subgenogroups (B2, B4, B5, C1, C2, and C4) of enterovirus 71 (EV71) between 1990 and 2007 in Yamagata, Japan. We measured neutralizing antibody (NT Ab) titers against those subgenogroup strains and the BrCr reference strain for antigenic analysis. Serological analysis of 83 residents in Yamagata in 2004 showed that differences in the NT Ab titer of each individual against the different subgenogroups were mostly within 4-fold. Furthermore, sera from guinea pigs, immunized with the B2 and C1 strains indicated cross-antigenicity among the seven different subgenogroups. In conclusion, our results showed that cross-antigenicity exists among EV71 strains from different subgenogroups circulating in the community through genomic evolution. Our results also suggest that eliciting neutralizing antibodies against one genotype is likely to confer cross-neutralization against other genotypes.

Outbreak of human metapneumovirus detected by use of the Vero E6 cell line in isolates collected in Yamagata, Japan, in 2004 and 2005.

A number of epidemiological studies have shown human metapneumovirus (hMPV) to be one of the most important viral agents associated with acute respiratory infections in humans. However, due to the difficulty in growing the virus, all epidemiological studies of hMPV infection have been performed on the basis of the molecular method. Thus, the development of a cell line suitable for the isolation of hMPV from clinical specimens is a crucial step for further research. Using the Vero E6 cell line, which could be stably maintained for 1 month without passage or medium change, we succeeded in isolating 79 strains from 4,112 specimens obtained in Yamagata, Japan, in 2004 and 2005. The total isolation rate was 1.9% (79/4,112). The monthly distribution revealed that hMPV infections occurred between February and April in 2004 and throughout most of the year in 2005. Phylogenetic analysis indicated that subgenogroup B2 was predominant in 2004, whereas three subgenogroups, A2, B1, and B2, had cocirculated in 2005. Although multiple subgenogroups cocirculated in 2005, each individual subgenogroup strain was found to predominate at specific sites. An infectivity assay of hMPV strains also indicated that the infection efficiency in Vero E6 cells was better than that in LLC-MK2 cells. Finally, we found that Vero E6 cells are useful for the isolation of hMPVs and that this utility might aid further research into hMPVs beyond the epidemiological data shown in this study.

Longitudinal investigation of epidemiologic feature of adenovirus infections in acute respiratory illnesses among children in Yamagata, Japan (1986-1991).

Using human embryonic fibroblast (HEF) and HEp-2 cell cultures, adenoviruses were isolated from 989 (3.7%) out of 26,793 pediatric patients with ARI in Yamagata, Japan from January, 1986 to December, 1991. All isolates were identified as types 1 (Ad1)-6 and no other serotypes were identified. Epidemiologic feature was different depending on the subgenus group. Ad1, 2, 5 and 6 (group C) were endemic and the infections occurred frequently in the summer season. Ad3 (group B) was epidemic in the autumn to winter season, although the virus was isolated every month in non-epidemic season. No seasonal distribution of Ad4 (group E) could be determined because the number of patients was limited. Neutralizing antibody positive ratio for group C were more than 40% at 1-2 years of age and almost 100% by 10 years of age but those for Ad3 (group B) were 40% by 10 years of age. The neutralizing antibodies for Ad4 (group E) or Ad7 (group B) became negative by 10 years of age. With group C infections, most cases were infants and young children less than 2 years of age, but Ad3 infections were older children with the peak at 4 and 5 years of age.

Cocirculation of two distinct groups of influenza C virus in Yamagata City, Japan.

The antigenic and genetic relationships among 15 strains of influenza C virus isolated between August, 1988, and May, 1990, in Yamagata City, Japan, were investigated. Based on the results of antigenic analysis with monoclonal antibodies to the hemagglutinin-esterase (HE) glycoproteins and oligonucleotide mapping of total vRNA, the isolates were divided into two distinct groups closely related to either C/Yamagata/26/81 or C/Aichi/1/81. Antigenic differences between two groups could be detected clearly with heterogeneous antiviral sera. Comparison of the HE gene sequences between the representative Yamagata isolates and the previous isolates from other countries showed that C/Yamagata/26/81-like and C/Aichi/1/81-like viruses had high degrees of nucleotide sequence homology with C/pig/Beijing/115/81 and C/Johannesburg/1/66, respectively. These observations suggest that two lineages of influenza C virus, markedly different from each other in both antigenic and genetic structures, were simultaneously present in Yamagata City during 1988-1990 and that viruses belonging to each of the two lineages may also be prevalent in other areas of Japan and even in other countries.

Six-year longitudinal analysis of adenovirus type 3 genome types isolated in Yamagata, Japan.

Five hundred eighty-seven adenovirus type 3 (Ad3) isolates were established from children with acute respiratory infections (ARI) from 1986 to 1991, in Yamagata, Japan. Ad3 could be found in almost all the months during the 6 years when two epidemics occurred, in 1987 and 1989. A molecular epidemiological study was done on 346 of the 587 isolates, using restriction endonucleases; BamHI, HindIII, SmaI, and BgIII were used. The Ad3 isolates were classified into seven genome types. The genetic differences among the seven genome types were < 0.9%, and their phylogenetic tree, estimated by the neighbor-joining method, correlated highly with their monthly distribution. One genome type predominated for 56 months, while the other six related genome types cocirculated for a short period. These results suggested that the predominant genome type of Ad3 might have been endemically perpetuated in the Yamagata area with minor genomic variations. Furthermore, the outbreaks of Ad3 may have been due not to the appearance of a new genome type but rather to the endemic genome type.

Community-acquired influenza C virus infection in children.

To clarify the epidemiologic and clinical features of community-acquired influenza C infection in children, we took specimens throughout the year from a larger number of patients with acute respiratory illnesses in a pediatric clinic in Yamagata, Japan. During a 2-year survey, 20 strains of influenza C virus were isolated from 13,426 specimens. These isolates were recovered throughout the year. The ages of patients with influenza C virus isolates ranged from 2 months to 11 years and peaked at the age of 1 year. The clinical diagnosis of patients with influenza C virus infection included bronchitis in one child and pneumonia in four. Community-acquired influenza C infection in children can cause a variety of respiratory illnesses that cannot be clinically differentiated from those caused by other viruses.

The herald waves of influenza virus infections detected in Sendai and Yamagata cities in 1985-1990.

The community surveillance of respiratory virus infections performed during 1985-1987 in Sendai and 1988-1990 in Yamagata has identified a total of five herald waves of influenza virus infections: A/H3N2 virus infections in 1985 and 1989, A/H1N1 virus infections in 1986 and 1988, and type B virus infections in 1989. To investigate the antigenic and genetic relationships between the herald wave and epidemic strains, influenza A/H1N1 viruses isolated during the 1986 and 1988 herald waves were compared with those isolated during the 1986-1987 and 1988-1989 epidemic seasons, respectively, utilizing hemagglutination inhibition tests with anti-hemagglutinin monoclonal antibodies and oligonucleotide mapping of total viral RNAs. The results showed that multiple variants differing in antigenic and genetic properties were cocirculating during the 1986 herald wave as well as during each of the two epidemics (only one strain was isolated in the 1988 herald wave). It was also observed that viruses which had the antigenic and/or genetic characteristics closely similar to those of the viruses circulating in the 1986 and 1988 herald waves, were isolated during the winters of 1986-1987 and 1988-1989, respectively.

[A clinical evaluation of cefdinir in pediatric infections].

Cefdinir (CFDN), a new oral cephalosporin, was administered to 10 patients with various infections and the following results were obtained. 1. Clinical responses in 10 patients (1 patient with rhinitis, 2 with sinusitis, 1 with pharyngitis, 1 with tonsillitis, 4 with scarlet fever and 1 with abscess) were excellent in 6 and good in 4 with an efficacy rate of 100%. 2. Eleven species of bacteria were isolated (3 of Staphylococcus aureus, 6 of Streptococcus pyogenes and 2 of Haemophilus influenzae) and all of them were eradicated by the treatment with CFDN. 3. No side effects or abnormal laboratory test values were noted. None of the patients refused to take the drug.

Human malignant melanoma cell line (HMV-II) for isolation of influenza C and parainfluenza viruses.

HMV-II, a human malignant melanoma cell line, was compared with other cell lines (MDCK, Vero, and LLC-MK2) and primary cultures of monkey kidney (PMK) cells for the isolation and quantification of influenza and parainfluenza viruses. HMV-II cells were superior to MDCK and LLC-MK2 cells in quantification of the influenza C virus and were used successfully in the isolation of the virus from clinical specimens. The HMV-II cell line was also more sensitive for isolating parainfluenza viruses from clinical specimens than were Vero and PMK cells; there was, however, no significant difference in the quantification of the viruses among these cultures. As far as influenza A and B viruses were concerned, the HMV-II cell line was significantly less sensitive than MDCK cells, and no virus was isolated from clinical specimens with HMV-II cells. Thus, HMV-II cells are useful for the isolation of influenza C and parainfluenza viruses as an alternative to embryonated hen's eggs and PMK cells.

Isolation and molecular characterization of a serotype 9 human rotavirus strain.

A human rotavirus strain, designated AU32, that belongs to serotype 9 was isolated and was compared by RNA-RNA hybridization with recently established two serotype 9 strains (WI61 and F45) as well as other prototype human strains. These three strains exhibited a very high degree of homology with one another and shared a high degree of homology with strains belonging to the Wa genogroup but not with strains belonging to either the DS-1 or AU-1 genogroup. These results suggest that genetic constellation of the serotype 9 strains is similar to that of the commonest human rotavirus despite the recent recognition of this serotype.

A human melanoma cell line highly susceptible to influenza C virus.

The relative amounts of influenza C virus-specific receptors of 25 established lines of mammalian cells including four lines of human malignant melanoma origin were compared by virus binding experiments. All the human melanoma cell cultures studied possessed two to four times more receptors than were found on MDCK cells, a cell line known to be highly susceptible to influenza C virus. It may therefore be a feature common to human melanoma cells that O-acetylsialic acid, a determinant for the attachment of influenza C virus, exists in large quantities on their surface. This is not specific to melanoma cells, however, since several human cell lines derived from lung cancer, gastric cancer, and placenta specimens also exhibited high levels of virus binding. Twenty of 25 virus-binding cell cultures were further examined for their ability to support the replication of influenza C virus. In the presence of trypsin (5 to 20 micrograms/ml), the virus was found to undergo multiple cycles of replication much more efficiently in the HMV-II line of human melanoma cells than in MDCK cells. Additionally, by using HMV-II cells as a host, we succeeded in isolating two influenza C strains (C/Yamagata/1/88, C/Yamagata/2/88) from 241 throat swabs collected from patients with acute respiratory illness.

Occurrence of changes in human rotavirus serotypes with concurrent changes in genomic RNA electropherotypes.

To investigate the serotypic and genetic diversity of human rotavirus strains, we have tested 513 and 519 fecal rotavirus specimens, respectively, by an enzyme-linked immunosorbent assay with serotype-specific monoclonal antibodies and by polyacrylamide gel electrophoresis of the segmented RNA genome. Of the 513 specimens, 375 were typed as serotype 1 (47.3%), serotype 2 (2.9%), serotype 3 (2.9%), or serotype 4 (17.7%). In addition, a presumptive new human serotype, tentatively referred to as serotype X in this paper, was found in 1.6% of the specimens tested. The remaining 138 specimens (26.9%) were untypeable. Considerable variation in relative frequency of circulating serotypes was observed with respect to geographic locations and observation periods. Rotavirus RNAs were visualized in 481 of 519 specimens tested. Of these, 415 were typed as 33 electropherotypes, many of which were infrequently detected and were restricted to single epidemics. Analysis of the 291 specimens whose electropherotypes and serotypes were available indicated clearly that a given RNA pattern always corresponded to a particular serotype. Heterogeneity of electropherotypes within a serotype was similarly observed in strains belonging to the four previously established serotypes. The results obtained in this study indicated that antigenic changes on the major neutralization antigen occurred always with concurrent changes of genomic RNA electropherotypes. On the other hand, serotypic changes could not be predicted from the changes in RNA electropherotypes.

Prevention of rotavirus infection by oral administration of cow colostrum containing antihumanrotavirus antibody.

After immunizing 8-month pregnant Holstein cows with human rotavirus, Wa strain, cow colostrum containing neutralizing antibody to human rotavirus, designated as Rota colostrum, was obtained. After randomly grouping 13 infants from a single orphanage, 6 infants received 20 ml of Rota colostrum every morning and 7 control infants received 20 ml of market milk. One month later, rotavirus associated diarrhea was observed in 6 of the 7 infants given milk and 1 out of the 6 infants given Rota colostrum. Orally administered Rota colostrum significantly protected infants from diarrhea caused by rotavirus (P less than 0.05). Two out of 5 Rota colostrum recipients who were free from diarrhea showed rises in complement fixation (CF) antibody titer after the rotavirus infection epidemic. Thus, Rota colostrum prevented the outbreak of diarrhea but did not prevent immunological responses to natural rotavirus infection. In the therapeutic trial Rota colostrum had no effect on duration of diarrhea, bowel movements or virus shedding in stool. However, there were no side-effects of Rota colostrum.

Effect and follow-up study on varicella vaccine.

Attenuated liver varicella vaccine (Oka strain) was used to vaccinate 242 children and 5 adults between August 1976 and December 1982; namely emergency vaccinations were given to 163 cases, including 35 high risk children, on 17 occasions, and non-emergency vaccinations were given to 84 cases including 7 high risk ones in remission. The viral doses varied from 250 to 3,000 PFU. Vaccinations prevented subsequent infection in all cases. Emergency vaccinations were given within 100 h after contact of the subjects with cases of varicella. Humoral and/or cellular immunity was acquired in 97.6% (40/41) of the high risk group and 91.8% (179/195) of the non-high risk group. As clinical reactions, rashes and fever developed in 43.9% (18/41) and in 17.0% (7/41) of high risk patients, and 7.8% (16/204) and 1.0% (2/204) of the non-high risk patients respectively. Reactions were generally slight, but were severe or atypical in 3 immunocompromized patients. Follow-up studies were carried out every year since 1980. Among the 41 high risk patients, herpes-zoster developed in 4, and varicella in 5 patients. Among the 179 non-high risk patients, there were no cases of herpes-zoster but 21 cases (12.3%) of varicella, which were mostly extremely mild. Six patients were revaccinated because of their humoral and/or cellular immunity decreased, and as a result acquired an immune response again. Criteria for varicella vaccination and details of the results of vaccination and follow-up studies are described.

Changing RNA patterns in rotaviruses of human origin: demonstration of a single dominant pattern at the start of an epidemic and various patterns thereafter.

The RNA of strains of rotavirus obtained from patients hospitalized with diarrhea during two winter epidemics of rotaviral infection in successive years (November 1981 through April 1982 and December 1982 through April 1983) was analyzed by polyacrylamide gel electrophoresis. A single dominant electropherotype was found during the first two or three months of each epidemic. In contrast, various electropherotypes were identified during the latter portion of each epidemic. RNA patterns of the rotaviral strains that were dominant during the early phase of the two epidemics were different from each other.

Sinus histiocytosis with massive lymphadenopathy. A histogenic analysis of histiocytes found in the fourth Japanese case.

The present paper deals with immunohistochemical and ultrastructural study of the lymph nodes of sinus histiocytosis with massive lymphadenopathy (Rosai and Dorfman, SHML) of a 12-year-old Japanese boy. This is the fourth case in Japan. Osseous manifestation was also found in the bilateral ulnae. With hallmarks of S-100 protein and interdigitating cytoplasmic extensions, the phagocytizing histiocytes proliferating in the sinuses were considered to be derived mostly from interdigitating cells in the paracortex or T cell dependent area, which have heretofore been regarded as nonphagocytizing. Furthermore, it is most interesting that lymphoid cells bearing thymic cortical cell-antigen (OKT 6) were increasingly recognized in the patient's peripheral blood. These results suggested that SHML is a specialized reactive histiocytosis analogous to histiocytosis X and histiocytic medullary reticulosis.