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Biomedical subjects

G Gerna

Publications and source records attributed to G Gerna.

At least 163 records · Page 9Linked to original sources
PubMed1985

Human enteric coronaviruses: antigenic relatedness to human coronavirus OC43 and possible etiologic role in viral gastroenteritis.

In a group of infants with acute nonbacterial gastroenteritis, examination of paired sera for antibody to human coronavirus (HCV) OC43 and neonatal calf diarrhea coronavirus showed a peculiar pattern of serological response, restricted only to HCV OC43 surface antigens, in a significantly higher proportion than among age-matched controls. In another group of infants and young children with acute nonbacterial gastroenteritis, fecal excretion of coronavirus-like particles was detected by electron microscopy in 34 (16.3%) of 208 patients as compared with three (1.6%) of 182 controls (P less than .01). Two strains of human enteric coronavirus (HECV) were purified from stools of two patients, and immune sera were raised in mice and guinea pigs. Immune electron microscopy showed a two-way cross-reactivity between HECV and HCV OC43 when tested with immune sera and convalescent-phase sera from patients with infection due to HECV or HCV OC43.

Animals↗
PubMed1985

Characterization of serotypes of human rotavirus strains by solid-phase immune electron microscopy.

Serotyping of human rotaviruses (HRVs) by neutralization requires the previous adaptation of strains to growth in cell cultures, which is often unsuccessful. By using the solid-phase immune electron microscopy (SPIEM) technique with protein A and type-specific, cross-adsorbed, polyclonal immune sera, we divided 40 previously typed culture-adapted strains into the same four serotypes distinguished by neutralization, but HRV strains could also be typed directly on stool extracts. Of 171 HRV strains tested by SPIEM, 163 were typed as a single serotype, two were shown to be mixed serotypes, three could not be typed since they were partially antibody-coated, and three were lacking the common group antigen (atypical rotaviruses or pararotaviruses). In addition, strains of serotype 4 could be classified by SPIEM into two subtypes, 4A and 4B. Overall, strains of serotype 1 were detected in nearly 50% of the 171 HRV-positive stools examined by SPIEM, strains of either serotype 2 or 4 in about 20%, and strains of serotype 3 in nearly 10%. Although the data were too scarce to allow for definite conclusions, the prevalence of the four serotypes appeared to change with the geographic area and the year.

Animals↗
PubMed1984

Subgrouping of human rotavirus strains by complement fixation, indirect double-antibody sandwich enzyme-linked immunosorbent assay and solid-phase immune electron microscopy.

Complement fixation (CF), indirect double-antibody sandwich (DAS) enzyme-linked immunosorbent assay (ELISA) and solid-phase immune electron microscopy (SPIEM) were compared for their ability to subgroup 73 human rotavirus (HRV) strains from infants and young children with gastroenteritis admitted to one or the other of two different hospitals of Northern Italy. By both indirect DAS ELISA and SPIEM all 73 HRV strains were classified into one or the other of two subgroups. By CF only 67 strains could be subgrouped, as six HRV-positive stools showed anticomplementary activity which could not be eliminated. Indirect DAS ELISA required subgroup-specific, unabsorbed antisera from two different animal species. For SPIEM two antisera from a single animal species were needed, but they had to be absorbed with single-shelled bovine rotavirus for HRV subgrouping to be reliable. Indirect DAS ELISA appeared to be the technique most suitable for extensive application in epidemiological studies of HRV infections by different subgroups. However, SPIEM allowed rapid subgrouping of HRV in stool specimens showing anticomplementary activity in the CF test or non-specific reactions in the ELISA test. In one area of Northern Italy the prevalence of subgroup I HRV infections was 7.8 per cent, while in another it reached 68.1 per cent in the same period.

Antigens, Viral↗
PubMed1984

Serotyping of cell culture-adapted subgroup 2 human rotavirus strains by neutralization.

Nine human rotavirus strains from stools of infants with gastroenteritis were serially propagated in MA-104 cell cultures. All strains were identified as subgroup 2 rotaviruses by RNA gel electrophoresis, complement fixation, and enzyme-linked immunosorbent assay. The human rotavirus strains were propagated for 15 to 20 passages and then used for immunization of guinea pigs and rabbits. Animal antisera were also raised against a subgroup 1 human strain purified from stools and against the cell culture-adapted Wa strain, a reference subgroup 2 rotavirus of human origin. Cross-neutralization studies revealed the existence of two distinct serotypes within the cell culture-adapted subgroup 2 human rotaviruses: strains related and unrelated to strain Wa were classified as serotypes 1 and 3, respectively. Results with convalescent-phase sera from infants with primary rotavirus infections confirmed the existence of two serotypes within subgroup 2, and the serotypes responsible for primary subgroup 2 infections could be determined on the basis of the neutralizing reactivity of convalescent sera.

Cells, Cultured↗
PubMed1984

Rapid serotyping of human rotavirus strains by solid-phase immune electron microscopy.

Nine cell culture-adapted, as well as 30 clinical, human rotavirus (HRV) strains from fecal extracts of children with primary HRV infection were typed by rapid solid-phase immune electron microscopy with protein A and absorbed DS-1 (HRV serotype 2), Wa (serotype 1), and VA70 (assumed serotype 3) rabbit immune sera. As a reference typing test for cell culture-adapted strains, the neutralization assay was used, whereas for noncultivatable strains typing was done for comparison, indirectly, based upon the differential neutralization reactivity of convalescent-phase serum samples from patients with primary HRV infection versus the three reference HRV serotypes. Typing results by solid-phase immune electron microscopy for all strains examined were in complete agreement with those obtained by the neutralization assay, both on cell culture-adapted strains with the three reference rabbit antisera and on three reference HRV strains with human convalescent-phase serum samples. Since adaptation to growth in cell cultures of clinical HRV strains from stool specimens is a time-consuming procedure and is often unsuccessful, solid-phase immune electron microscopy is preferred over the neutralization assay, giving results in about 16 h and also allowing typing of HRV strains from stool specimens low in virus particles. In addition, HRV strains reacting differently from the three reference serotypes may be easily selected by solid-phase immune electron microscopy for further characterization, as was the case for one strain in this study.

Enzyme-Linked Immunosorbent Assay↗
PubMed1984

Coronaviruses and gastroenteritis: evidence of antigenic relatedness between human enteric coronavirus strains and human coronavirus OC43.

A peculiar pattern of antibody response to human coronavirus (HCV) OC43 and neonatal calf diarrhea coronavirus (NCDCV) was observed in a significantly higher proportion of children with gastroenteritis (GE) than controls. It was directed only to OC43 surface antigens and appeared to be quite different form that observed in OC43 respiratory infections, in which an antibody response to both OC43 and NCDCV surface and internal antigens was found. Subsequently, fecal excretion of CV-like particles was detected by electron microscopy in a significantly higher proportion of infants and young children with acute GE as compared to controls. Immune electron microscopy showed a two-way cross-reactivity between HCV OC43 and human enteric coronavirus (HECV), both using immune sera (raised in animals immunized with HECV strains purified from stools of two patients) and patients' convalescent sera. These data show that HECVs are antigenically related to HCV OC43 and could be somewhat involved in the etiology of GE in infants and young children.

Acute Disease↗
PubMed1984

Herpes simplex virus latency in immunosuppressed mice.

To determine the role of antibodies in establishing Herpes simplex virus (HSV) latency, immunosuppressed Swiss mice were experimentally infected in the right hind footpad with a HSV-1 x HSV-2 recombinant (C6D) with low virulence. Immunosuppression was induced by repeated intraperitoneal inoculations of Cyclophosphamide (CY) and the production of antibodies to C6D in immunosuppressed animals was monitored by Enzyme Linked Immunosorbent Assay (ELISA). Within 21 days after inoculation, C6D was able to establish a latent infection of lumbosacral spinal ganglia in both normal and CY-treated immunosuppressed animals. The data presented indicate that detectable production of antibodies is not necessary to induce HSV latency in spinal ganglia.

Animals↗
PubMed1984

Kinetics of virus-specific IgG and IgM antibody response in patas monkeys experimentally infected with Delta herpesvirus by enzyme-linked immunosorbent assay.

The kinetics of virus-specific IgG and IgM antibody response in patas monkeys experimentally infected with Delta herpesvirus (DHV), was studied using enzyme-linked immunosorbent assay (ELISA). An indirect ELISA (IE) test was used for DHV IgG determination, whereas a "double sandwich" (triple antibody layer) ELISA (DSE) test was found to be very sensitive for DHV IgM detection. In DSE test DHV IgG appeared to interfere with IgM determination only in sera containing DHV IgG levels at least 100 times higher than IgM. IgM antibodies appeared 5-8 days after monkey infection, reached a peak titer in 5-7 days, and after 7 days started to drop in titer and disappeared within two months. IgG antibodies appeared 5 days later than IgM, reaching the plateau in the following 7 days and then remaining stable for at least 2 months. Experimental infection of the patas monkey with DHV appears to be a good animal model for human varicella. IE for IgG and DSE for IgM detection are sensitive ELISA tests for determination of the immune response to DHV infection in patas monkeys.

Animals↗
PubMed1984

Diagnosis of acute non-bacterial gastroenteritis by rotavirus detection and serology.

In 127 infants and young children suffering from acute non-bacterial gastroenteritis, diagnosis of rotavirus infection was done by virus detection and serology. Human rotavirus (HRV) detection was performed by direct electron microscopy (EM), conventional immune electron microscopy (IEM) and/or solid phase immune electron microscopy ( SPIEM ); rotavirus antigens were detected by indirect double-antibody sandwich (DAS) ELISA and HRV isolation was attempted in MA-104 or LLC-MK2 cell cultures. HRV serology was done on paired sera from all the patients by the indirect immunoperoxidase antibody (IPA) technique for HRV IgG determination, and by an indirect ELISA method using a purified HRV Wa strain as a solid phase. HRV particles were detected by EM and/or IEM in 53 cases (41.7%) and by SPIEM in 5 additional cases; HRV antigens were demonstrated by indirect DAS ELISA in the same 53 cases, whereas 40 cases (31.4%) were positive for HRV isolation in cell cultures. Sixty-four patients (50.3%) seroconverted by IPA and ELISA, including all the cases (58) positive for rotavirus detection in stools and 6 additional cases. Thus, SPIEM appears to be the most sensitive technique for detecting a few virus particles in stool specimens, but HRV serology is the most sensitive method for diagnosing HRV infections retrospectively, when paired sera are drawn at an appropriate time. However, EM possess the great advantage of detecting in fecal specimens viral agents other than rotaviruses, such as adenoviruses, enteric coronaviruses, small round viruses, astroviruses and others.

Antibodies, Viral↗
PubMed1983

Herpes simplex virus and human cancer. III. Search for relationship of herpes simplex antibodies and cervical dysplasia and labial neoplasia.

We employed the enzyme-linked immunosorbent assay (ELISA), indirect hemagglutination (IHA), and complement fixation (CF) methods to measure antibody titer to herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in patients affected by labial tumors or cervical dysplasias. No relationship of antibody titer to HSV-1 and labial tumors was detected by any of the three methods. Association between antibody titer to HSV-2 and cervical dysplasias was revealed by IHA (p less than 0.05) and ELISA (p less than 0.001); CF tests were negative. Moreover, we assayed for HSV-specific antigens in cell cultures derived from labial tumors and cervical dysplasias. In cultures from labial tumors, it was not possible to detect HSV-specific antigens. Of the 25 cultures derived from cervical dysplasias, HSV antigens were found in only 3 cultures.

Adult↗
PubMed1983

Typing of herpes simplex virus isolates by enzyme-linked immunosorbent assay: comparison between indirect and double-antibody sandwich techniques.

Indirect and double-antibody sandwich enzyme-linked immunosorbent assay techniques were compared for serotyping 42 herpes simplex virus isolates. Both procedures gave similar results, which were in complete agreement with those obtained by inhibition of the indirect hemagglutination test. The indirect technique proved to be as specific as the double-antibody sandwich enzyme-linked immunosorbent assay, but simpler and cheaper.

Antibodies, Viral↗
PubMed1982

Grouping of human adenoviruses by early antigen reactivity.

Prototype strains of human adenovirus (AV) (serotypes 1-35) as well as 49 wild strains were studied for reactivity of early antigens (EAs) with type-specific rabbit immune sera, using the immunoperoxidase antibody technique for determination of virus-specific IgG. The EAs of all AV serotypes belonging to one group reacted strongly with all type-specific immune sera of the homologous group. Reactivity with antisera to heterologous groups was moderate or absent except for the EAs of AV type 4, which reacted strongly with all AV-immune sera. Thus, on the basis of EA reactivity, all AV strains appeared to fall into five distinct groups (corresponding to DNA homology groups): group A, types 12, 18, and 31; group B, types 3, 7, 11, 14, 16, 21, 34, and 35; group C, types 1, 2, 5, and 6; group D, types 8-10, 13, 15, 17, 19, 20, 22-30, 32, and 33; and group E, type 4. For diagnostic virology, EA grouping is a valid alternative to differential hemagglutination; it is more complete, and all AV strains can be rapidly classified.

Adenoviruses, Human↗
PubMed1982

Reactivity of human coronavirus OC43 and neonatal calf diarrhoea coronavirus membrane-associated antigens.

Human embryonic lung fibroblast cultures and Vero cell cultures infected with cell culture-adapted strains of human coronavirus (HCV) OC43 or neonatal calf diarrhoea coronavirus (NCDCV) were shown to possess highly cross-reactive membrane-associated antigens (MAA) by the indirect fluorescent antibody technique (IFAMA). MAA appeared 3 h post-infection, concurrently with the appearance of cytoplasmic antigens. Electron microscopic observations of cell cultures infected with either coronavirus strain and labelled with the immunoperoxidase antibody (IPA) technique for MAA detection showed that MAA consisted mainly of a strongly labelled, discontinuous, brush-like layer of amorphous material, strictly associated with the infected cell membrane. By light microscopy, reactivity of MAA with homologous and heterologous immune serum was similar to that of antigens detected by IPA in ethanol-fixed infected cells. IPA and IFAMA, but not haemagglutination-inhibiting (HI) and neutralizing (Nt) antibody, were strongly decreased by absorption of immune sera with trypsin-treated glutaraldehyde-fixed cell cultures infected with homologous virus. MAA IgG antibodies were detected by IFAMA in both human and animal sera. Sera from infants showing an HI and Nt, but not an IPA, antibody response to HCV OC43 were also free of detectable IFAMA antibody to HCV OC43.

Animals↗
PubMed1981

Antigenic and biological relationships between human coronavirus OC43 and neonatal calf diarrhoea coronavirus.

Monospecific antisera were prepared in mice to human coronavirus OC43 and neonatal calf diarrhoea coronavirus (NCDCV) which had been previously adapted to growth in suckling mouse brain. Brain suspension from infected suckling mice was used as immunogen. The antigenic relationship between OC43 and NCDCV was studied by the indirect immunoperoxidase antibody technique, by the haemagglutination-inhibition (HI) test and a new infectious centre-reduction neutralization test. In mouse immune sera, a two-way cross-reaction between OC43 and NCDCV was detected. However, the antigenic relationship appeared to be closer for internal (as shown by immunoperoxidase staining) as compared to surface antigens (as shown by HI and neutralization). In primary infections of natural hosts there was a high degree of cross-reactivity between the two coronavirus strains for both surface and internal antigens, and homologous and heterologous titres were consistently within an eightfold dilution difference by all tests. Most human adults and calves had antibody to both OC43 and NCDCV and geometric mean titres of homologous antibody were higher than titres of heterologous antibody. Although OC43 and NCDCV share antigenic determinants, they possessed several different biological properties, including plaque morphology by the infectious centre assay, agglutination of 1-day-old chick erythrocytes and resistance of haemagglutinin to physical and chemical treatments.

Antibodies, Viral↗
PubMed1981

Antibody to human adenovirus early antigens during acute adenovirus infections.

The antibody (Ab) response to human adenovirus (AV) early antigens (EA) in acute AV infections was studied by the immunoperoxidase antibody technique for determining virus-specific immunoglobulin G (IPA-IgG). AV-EA-Ab appeared about 5 days after the onset of clinical symptoms, reached a peak 15 to 30 days later, and declined in titer after a few months. The staining pattern in the IPA-IgG reaction was usually nuclear; however, in most primary infections sera obtained 2 to 3 weeks after the onset of infection also showed cytoplasmic staining. According to the recent deoxyribonucleic acid homology classification of human AV in five groups (A, B, C, D, and E), the EA-Ab response in primary human infections was found to be group specific for groups A to D, with consistent cross-reactions with group E. In AV type 4 (group E) infections, EA-Ab appeared to be directed against all groups, although at different titers. Comparable results were obtained using AV type-specific animal antisera. Thus, it was concluded that group E shares EA with all the other groups. Furthermore, in each individual with remote AV infections, the current infection elicited an anamnestic EA-Ab response to all AV groups responsible for previous infections. In diagnostic virology these findings can be applied to the rapid diagnosis of a current for recent) AV infection on a single serum sample and to the rapid group identification of clinical isolates by using type-specific animal antisera containing EA-Ab (one for each group) or sera from patients with primary AV infections.

Acute Disease↗