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PubMed1988

Rotavirus-specific cytotoxic T lymphocytes cross-react with target cells infected with different rotavirus serotypes.

Splenocytes from adult C57BL6 (H-2b) mice orally inoculated with nonmurine rotaviruses lysed syngeneic rotavirus-infected target cells. Cytotoxic T lymphocytes (CTLs) were responsible for this cytotoxic activity. Cytotoxic activity was (i) detected 7 days after primary oral inoculation; (ii) not detected in uninoculated animals; (iii) specific for rotavirus-infected target cells; (iv) eliminated by treatment with Thy 1.2-specific immunoglobulin M and complement; and (v) restricted at H-2Db. In addition, rotavirus-specific CTLs cross-reacted with target cells infected with different human or animal rotavirus serotypes. Heterotypic protection against rotavirus challenge may be mediated by cross-reactive CTLs.

Animals↗

PubMed1988

Molecular and antigenic characterization of porcine rotavirus YM, a possible new rotavirus serotype.

In 1983, we isolated a porcine rotavirus (strain YM) that was prevalent in several regions of Mexico, as judged by the frequency of its characteristic electropherotype. By a focus reduction neutralization test, rotavirus YM was clearly distinguished from prototype rotavirus strains belonging to serotypes 1 (Wa), 2 (S2), 3 (SA11), 4 (ST3), 5 (OSU), and 6 (NCDV). Minor, one-way cross-neutralization (1 to 5%) was observed when antisera to the various rotavirus strains were incubated with rotavirus YM. In addition, the YM virus was not neutralized by neutralizing monoclonal antibodies with specificity to serotypes 1, 2, 3, and 5. The subgroup of the virus was determined to be I by enzyme-linked immunosorbent assay. To characterize the serotype-specific glycoprotein of the virus at the molecular level, we cloned and sequenced the gene coding for VP7. Comparison of the deduced amino acid sequence with reported homologous sequences from human and animal rotavirus strains belonging to six different serotypes further supported the distinct immunological identity of the YM VP7 protein.

Amino Acid Sequence↗

PubMed1991

Relation of VP7 amino acid sequence to monoclonal antibody neutralization of rotavirus and rotavirus monotype.

The neutralization epitopes of the VP7 of human rotavirus RV-4 were studied by using five neutralizing mouse monoclonal antibodies to select virus variants resistant to neutralization by each of the antibodies. Antibody resistance patterns and sequence analysis of the RV-4 variants revealed that at least four sites on VP7, located at amino acids 94 (region A), 147 to 148 (region B), 213 (region C), and 291, are involved in neutralization of the human G1 rotavirus RV-4. The A-region site elicited antibody cross-reactive between G types and showed species-restricted immunodominance not related to carbohydrate attachment. The monotype 1b rotavirus M37 lacked this site. The B region contained strain-specific and cross-reactive sites, absent in monotype 1c rotaviruses. The C-region site was present in all G1 rotaviruses tested. Monotype 1a rotaviruses contained all these sites of neutralization. Virus monotype and sensitivity to monoclonal antibody neutralization usually related to the presence of a particular amino acid(s) at or next to the positions at which the mutations were selected in the virus variants.

Amino Acid Sequence↗

PubMed1987

Protection against severe rotavirus diarrhoea by rhesus rotavirus vaccine in Venezuelan infants.

The efficacy of the rhesus rotavirus vaccine candidate MMU-18006 was evaluated in a longitudinal double-blind field trial in Caracas, Venezuela. 247 infants aged 1-10 months were studied and followed for up to 1 year (201 completed the 1-year surveillance): 123 received a dose of 10(4) plaque-forming units of the vaccine orally and 124 received placebo. 21 episodes of rotavirus diarrhoea were detected, 16 in the controls and 5 in the vaccines: vaccine efficacy against any rotavirus diarrhoea was thus 68%. In the 1-5-month-old group the vaccine efficacy was 93%; only 1 episode of rotavirus diarrhoea was detected in 68 vaccinees and 15 such illnesses were observed in 65 controls (p less than 0.0001). For the entire study group vaccine efficacy was 100% against the most severe rotavirus diarrhoeal episodes.

Antibodies, Viral↗

PubMed1986

Rotavirus fecal IgA antibody response in adults challenged with human rotavirus.

Our studies of rotavirus challenge in adult volunteers enabled us to evaluate the relationship of pre-existing antirotavirus fecal IgA antibody to infection and illness and to investigate the local response to this infection. No relationship could be found between the pre-existing levels of fecal antirotavirus IgA antibody and protection from infection or illness. A greater than six-fold increase in the level of antibody was seen in 16/19 infected volunteers with determinable increases but in 0/15 controls who received less than the minimal infectious dose of rotavirus. Antibody levels increased rapidly in infected volunteers and were consistent with an anamnestic response. Two of seven volunteers who received an infectious dose of rotavirus but were considered uninfected on the basis of other laboratory methods had greater than or equal to six-fold increases of fecal antibody and one of these experienced symptoms compatible with a rotavirus infection. This finding indicates that an increase in fecal antibody may be a reliable indicator of rotavirus infection even in the absence of detectable shedding or seroconversion.

Adolescent↗

PubMed1994

Naturally occurring dual infection with human and bovine rotaviruses as suggested by the recovery of G1P8 and G1P5 rotaviruses from a single patient.

Culture adaptation of rotaviruses from an infant with severe diarrhea in Cincinnati, Ohio, yielded not only a virus with the original RNA electropherotype (CJN) but also rotaviruses with other electropherotypes, the most dominant of which was called CJN-M [Ward RL, Knowlton DR, Schiff GM, Hoshino Y, Greenberg HB (1988) in J Virol 62: 1543-1549]. RNA-RNA hybridization and sequencing studies indicated that CJN was a typical G1P8 human rotavirus while CJN-M was a G1P5 strain and contained four gene segments (including segment 4) of a bovine rotavirus. Thus, the infant was apparently dually infected with human and bovine rotaviruses.

Animals↗

PubMed1996

Divergence of VP7 genes of G1 rotaviruses isolated from infants vaccinated with reassortant rhesus rotaviruses.

A large placebo-controlled efficacy trial of the rhesus tetravalent (RRV-TV) and serotype G1 monovalent (RRV-S1) rotavirus vaccines was conducted in 1991-1992 at 24 sites across the United States. Protection was 49% and 54% against all diarrhea but 80% and 69% against very severe gastroenteritis for the two vaccines, respectively. Post-vaccination neutralizing antibody titers to the G1 Wa strain, whose VP7 protein is nearly identical to that of the D strain of rotavirus contained in both vaccines, did not correlate with protection against subsequent illness with G1 strains. This result raised the possibility that in infants who developed post-vaccination neutralizing antibody to Wa, breakthrough (i.e., vaccine failure-the occurrence of rotavirus diarrhea after immunization) may have been due to infection by G1 strains that were sufficiently antigenically distinct from the vaccine strain to evade the neutralizing antibodies elicited by vaccination. To test this hypothesis, we initially compared post-vaccination neutralizing antibody titers of vaccinees against Wa and G1 breakthrough strains using sera from subjects who experienced breakthrough. Post-immunization neutralizing antibody titers to Wa elicited by vaccination were significantly (P < 0.001) greater than to the breakthrough strains subsequently obtained from these subjects. This difference did not, however, correlate with lack of protection since similar differences in titer to Wa and breakthrough strains were found using post-vaccination sera from vaccinees who either experienced asymptomatic rotavirus infections or no infections. To determine the genetic basis for these differences, we compared the VP7 gene sequences of Wa with vaccine strain D, 12 G1 breakthrough strains, and 3 G1 control strains isolated during the same trial from placebo recipients. All breakthrough strains were distinct from Wa and D in antigenically important regions throughout the VP7 protein, but these differences were conserved between breakthrough and placebo strains. Furthermore, a comparative analysis of the deduced amino sequences form VP7 genes of G1 rotaviruses from 12 countries indicated that four distinct lineages have evolved. All breakthrough and control strains from the U.S. vaccine trial were in a lineage different from strain D, the serotype G1 vaccine strain. Although the overall results do not support our original hypothesis that immune selection of antigenically distinct escape mutants led to vaccine breakthrough in subjects with a neutralization response to Wa, it cannot be excluded that breakthrough could be partially due to antigenic differences in the VP7 proteins of currently circulating G1 strains.

Amino Acid Sequence↗

PubMed2005

A porcine G9 rotavirus strain shares neutralization and VP7 phylogenetic sequence lineage 3 characteristics with contemporary human G9 rotavirus strains.

Of five globally important VP7 (G) serotypes (G1-4 and 9) of group A rotaviruses (the single most important etiologic agents of infantile diarrhea worldwide), G9 continues to attract considerable attention because of its unique natural history. Serotype G9 rotavirus was isolated from a child with diarrhea first in the United States in 1983 and subsequently in Japan in 1985. Curiously, soon after their detection, G9 rotaviruses were not detected for about a decade in both countries and then reemerged in both countries in the mid-1990s. Unexpectedly, however, such reemerged G9 strains were distinct genetically and molecularly from those isolated in the 1980s. Thus, the origin of the reemerged G9 viruses remains an enigma. Sequence analysis has demonstrated that the G9 rotavirus VP7 gene belongs to one of at least three phylogenetic lineages: lineage 1 (strains isolated in the 1980s in the United States and Japan), lineage 2 (strains first isolated in 1986 and exclusively in India thus far), and lineage 3 (strains that emerged/reemerged in the mid-1990s). Currently, lineage 3 G9 viruses are the most frequently detected G9 strains globally. We characterized a porcine rotavirus (A2 strain) isolated in the United States that was known to belong to the P[7] genotype but had not been serotyped by neutralization. The A2 strain was found to bear serotype G9 and P9 specificities as well as NSP4 [B] and subgroup I characteristics. By VP7-specific neutralization, the porcine G9 strain was more closely related to lineage 3 viruses than to lineage 1 or 2 viruses. Furthermore, by sequence analysis, the A2 VP7 was shown to belong to lineage 3 G9. These findings raise intriguing questions regarding possible explanations for the emergence of variations among the G9 strains.

Amino Acid Sequence↗

PubMed1999

Effects of different adjuvants on rotavirus antibody responses and protection in mice following intramuscular immunization with inactivated rotavirus.

I.m. immunization of mice with inactivated rotavirus particles protects against subsequent infection. To optimize protection, the effects of different adjuvants (QS-21, QS-7, QUIL A, PCPP and RAS) with potential for human use were compared. Twenty-eight days after i.m. immunization with 20 microg of purified, UV/psoralen-inactivated murine rotavirus (EDIM), either with or without adjuvant, BALB/c mice were orally challenged with live EDIM and virus shedding was measured. All five adjuvants stimulated large (P < 0.001) increases in rotavirus antibody, but significant differences were found between adjuvants. The order of rotavirus IgG responses, i.e. no adjuvant < RAS < QS-7 < Quil A < QS-21 < PCPP, was the same as the order of protection except that QS-21 and PCPP were reversed. These results establish the importance of adjuvants during i.m. immunization with rotavirus and identify those with the greatest potential.

Adjuvants, Immunologic↗

PubMed2005

A hexavalent human rotavirus-bovine rotavirus (UK) reassortant vaccine designed for use in developing countries and delivered in a schedule with the potential to eliminate the risk of intussusception.

There is an urgent need for a rotavirus vaccine, because up to 592,000 infants and young children <5 years old die each year from rotavirus diarrhea, predominantly in the developing countries. We have developed a tetravalent human-bovine rotavirus (UK) reassortant vaccine with VP7 (G) specificity for serotypes 1, 2, 3, and 4, which has been shown to be safe, immunogenic, and effective in preventing severe rotavirus diarrhea. However, because of the emergence of VP7 (G) serotype 9 as an epidemiologically important serotype and the importance of VP7 (G) serotype 8 in focal areas, we are planning to add human-bovine (UK) reassortants with G8 and G9 specificity to the tetravalent vaccine, thereby formulating a "designed" hexavalent vaccine for universal use. In addition, we propose that the vaccine be administered orally in a 2-dose schedule, with the first dose given at 0-4 weeks of age and the second dose given at 4-8 weeks of age, when infants are relatively refractory to developing intussusception, thereby avoiding the age period when naturally occurring intussusception is most prevalent (i.e., ages 3-4 months through age 9 months). In this way, there may be the potential to eliminate or at least significantly decrease the risk of intussusception associated with rotavirus vaccination.

Administration, Oral↗

PubMedDate not supplied

Prospects for development of a rotavirus vaccine against rotavirus diarrhea in infants and young children.

Major advances have been made in elucidating the etiologic agents of severe infantile diarrhea, and it is clear that rotaviruses are the single most important etiologic agents. Progress in the development of rotavirus vaccine candidates has also moved swiftly with the "Jennerian" approach, in which a related live, attenuated rotavirus strain from a nonhuman host is used as the immunizing antigen. If this strategy is not effective against all rotavirus serotypes, reassortant rotaviruses hold great promise for the development of a multivalent vaccine. Field trials with the "Jennerian" approach vaccines are under way, and phase 1 trials with the reassortants have been initiated.

Animals↗

PubMed1992

Seroepidemiologic evaluation of antibodies to rotavirus as correlates of the risk of clinically significant rotavirus diarrhea in rural Bangladesh.

A case-control study was conducted among children and adult women in rural Bangladesh to evaluate whether serologic immunity to rotavirus was associated with a lower risk of rotavirus diarrhea of sufficient severity to cause patients to seek medical care. Acute-phase sera from 219 cases of rotavirus diarrhea, detected among patients treated in three diarrheal treatment centers, were compared with sera from 477 contemporaneously selected community controls. Overall, serum IgG antirotavirus antibody titers were nearly one-fourth as high in cases as in controls (107 vs. 417 units/ml; P less than .001). Among persons aged greater than or equal to 8 months, in whom titers of maternal antirotavirus antibodies should have been negligible, even the lowest range of detectable titers (100-200 units/ml) was associated with a substantial (75%, P less than .05) reduction of the risk of rotavirus diarrhea. We conclude that titers of serum IgG antirotavirus antibodies induced by earlier infection were inversely related to the risk of clinically significant rotavirus diarrhea.

Adult↗

PubMed1993

Protection conferred by neonatal rotavirus infection against subsequent rotavirus diarrhea.

A cohort of newborns in New Delhi who were nosocomially infected with rotavirus during their first days of life were followed twice weekly for 14-23 months to determine whether neonatal infection protected them against subsequent episodes of rotavirus diarrhea. Infection occurred in 60% by the fourth day of life, was asymptomatic, and was caused predominantly by an unusual rotavirus strain (G9 P11) not previously identified in humans. The 148 children with neonatal rotavirus infection had 46% fewer attacks of rotavirus diarrhea in the follow-up period than the 56 infants without nosocomial infection (0.23 vs. 0.42 episodes/child-year, P < .05). This protection was concentrated among infants in their first year of life and was not associated with a significant decrease in disease severity. Consideration of this strain as a vaccine candidate will require further assessment of its natural protection under field conditions.

Cohort Studies↗

PubMed1994

Anti-rotavirus G type-specific and isotype-specific antibodies in children with natural rotavirus infections.

Serum VP7 (G) type- and isotype-specific anti-rotavirus antibodies were assessed among children monitored longitudinally over one or two rotavirus seasons in day care centers. Seventy-five pairs of blood specimens from 63 children were tested for anti-rotavirus antibodies. Stool specimens were collected weekly and tested for rotavirus antigen. G typing of detected rotaviruses showed that seven outbreaks of G1 and one of G3 occurred during the two seasons. G type-specific responses to the outbreak strain occurred among 79% of infected children and 9% of children with infection not detected (P < .001). Of children infected with G1, 54% had a heterotypic response; they were older (P = .048) and had higher preexisting G1 antibody levels than children who had only homotypic responses (P = .012). Higher IgA, IgG, and homotypic antibody levels to the antigenic site C of the G1 and G3 VP7s correlated with protection against infection and illness, homotypic antibody independently of IgA or IgG titers.

Antibodies, Viral↗

PubMed1998

Longitudinal studies of neutralizing antibody responses to rotavirus in stools and sera of children following severe rotavirus gastroenteritis.

Rotavirus-neutralizing antibody responses in sera and stools of children hospitalized with rotavirus gastroenteritis and then monitored longitudinally were optimally detected by using local rotavirus strains. Stool responses were highest on days 5 to 8 after the onset of diarrhea. Longitudinal monitoring suggested that serum neutralizing antibody responses were a more useful measure of severely symptomatic rotavirus infection than stool responses but that stool antibody responses may be a useful measure of rotavirus immunity.

Antibodies, Viral↗

PubMed1987

Age-related infections with rotavirus, rotaviruslike virus, and atypical rotavirus in turkey flocks.

The genome electropherotyping technique was used in longitudinal surveys to detect group A rotavirus, rotaviruslike virus (RVLV), atypical rotavirus (ATR), and reovirus in intestinal contents or fecal specimens collected from turkeys in 10 commercial and 2 research station flocks. These viruses were detected in turkeys from 8 to 10 commercial flocks surveyed. Of 278 specimens collected from turkeys less then 29 days old in commercial flocks, 79 (28.4%) contained one or more viruses, whereas only 1 of 120 specimens collected from turkeys older than 28 days had virus. Viruses were detected in commercial turkeys between 3 and 35 days old, and over a third of the specimens collected from birds during their first week of life were positive for group A rotavirus. Between 8 and 28 days of age, commercial turkeys were infected with group A rotavirus, RVLV, ATR, and reovirus. ATR was the only virus detected in birds older than 28 days. Overall, group A rotavirus and RVLV were each detected in 39 specimens, and ATR was detected in 7 specimens; reovirus was detected in 2 specimens. Eight of the positive specimens contained two viruses. All 102 specimens collected from turkeys 1 to 56 days old in the two research station flocks were negative for virus.

Aging↗

PubMed1989

Direct identification of serotypes of natural human rotavirus isolates by hybridization using cDNA probes derived from segment 9 of the rotavirus genome.

Under stringent hybridization conditions, cDNA of segment 9 of the rotavirus genome, which codes for the viral protein VP7, permitted differentiation of serotypes of culture-grown rotaviruses and natural isolates of human rotaviruses directly from clinical specimens. This was evident for the following reasons. (i) The cDNA of one serotype selectively hybridized with the RNA of the same serotype of culture-grown rotaviruses. (ii) Natural isolates of the virus thus identified as serotype 2 were also those which gave the short electrophoretic pattern characteristic of the genome of serotype 2, subgroup 1 viruses. Isolates having the long electrophoretic pattern characteristic of the genome of subgroup 2 viruses were identified as serotype 1, 3, or 4 by this method. (iii) For patients who had previously undergone serological analysis, the serotypes being excreted were the same serotypes against which there was the most marked serum neutralizing antibody response. Although the virus population was genetically diverse, the preponderance of the population prevalent in Guangzhou and Foshan in each of the three successive years between 1982 and 1985 comprised a single serotype. The dominant serotype changed from one year to another, but there was minimal cocirculation of different serotypes in this community. All virus isolates belonged to serotype 1,2,3, or 4, and there was no evidence to suggest that the other human rotavirus serotypes were prevalent in this community.

Antigens, Viral↗

PubMed1994

Evaluation of an automated immunodiagnostic assay, VIDAS Rotavirus, for detection of rotavirus in fecal specimens.

Four hundred sixty-four fecal specimens were tested for rotavirus by three immunoassays, VIDAS Rotavirus (bioMérieux Vitek, Hazelwood, Mo.), Rotaclone (Cambridge Biotech Corporation, Worcester, Mass.), and Pathfinder Rotavirus (Sansfi Diagnostics Pasteur, Chaska, Minn.). Twenty-seven discordant specimens were evaluated by electron microscopy. The sensitivities, specificities, positive predictive values, and negative predictive values were 98, 99.3, 98.7, and 99%, respectively, for VIDAS Rotavirus; 100, 99, 98.1, and 100%, respectively, for Rotaclone; and 100, 92.4, 87.3, and 100%, respectively for Pathfinder Rotavirus.

Adolescent↗