摘要:

Glycoprotein B (gB) of human cytomegalovirus (CMV) is the major target protein of neutralizing antibodies, and four variant types are known. A previously reported polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method was modified by eliminating the cell culture step and amplifying a CMV fragment (corresponding to a.a. 441-450 of gB) by nested PCR. DNA was extracted from the sera of 27 pediatric bone marrow transplant recipients and subjected to nested PCR. Of the samples, 20 yielded PCR products, and the gB type was determined by RFLP. Of the 20 patients, 4 (20%) had gB type 1 (Towne type), 15 patients (75%) had gB type 2 (AD 169 type), and 1 patient (5%) had gB type 3. Previous studies showed that gB type was most common among Caucasians [Chou and Dennison: J Infect Dis 1991;163:1229-1234; Fries et al: J Infect Dis 1994;169:769-774]. Thus, gB genotypes seem to be distributed differently in Caucasians and Japanese. Further, nucleotide sequence analysis of the amplified region revealed that all the type 2 viruses had the same amino acid sequences. The type 3 sample had a novel amino acid substitution at position 498. Of the type 1 samples, 3 had amino acid substitutions in various positions: 1 sample at position 493,1 sample at position 447 and 1 sample at position 452, 493 and 498.

ISSN:0300-5526    

DOI:10.1159/000150549

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The llheus (ILH) virus has long been known to belong to group B of the arboviruses. Previous attempts to relate it to existing serogroups within the Flavivirus genus using conventional serological techniques such as hemagglutination inhibition, neutralization and complement fixation tests have been inconclusive. We have first used denaturing gel electrophoresis to estimate the molecular weight of immunoprecipitated radiolabeled viral proteins and the cross-reactivity among ILH proteins and hyperimmune sera to several flaviviruses only from the mosquito-borne encephalitis virus serogroups. The estimated molecular weight for the three proteins was in the same order of magnitude, as previously established, for mosquito-borne flaviviruses. Cross-immunoprecipitation tests showed that NS3 protein is the most cross-reactive. Partial nucleotide sequence analyses of the NS3 gene, corresponding to an area linking the helicase and the RNA triphosphatase domains, revealed that ILH virus is very closely related to the Japanese encephalitis virus complex confirming earlier serological data.

ISSN:0300-5526    

DOI:10.1159/000150550

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Genome segments 2 and 3 were completely sequenced for one virulent and one avirulent bluetongue serotype 17 (BLU-17). These two segments were previously shown to exhibit virulence-associated markers. The marker on segment 2 was characterized as a change in the neutralization domain on its protein product, VP2. The nucleotide sequences for segments 2 were 94.5% identical, and their predicted proteins differed by 34 amino acids or 3.7%. Three clusters of variability were identified which may be involved with viral neutralization. These variable regions were compared to mutations for published monoclonal antibody-resistant variants of BLU. The marker on segment 3 was characterized as a mobility shift in polyacrylamide gel electrophoresis (PAGE). The nucleotide sequences were 95.0% identical, and their predicted proteins differed by four amino acids or 0.4%. These amino acid changes were relatively conserved; therefore, they are not likely responsible for virulence. The segment 3 sequences were compared to published sequences, and evidence was found to suggest that the virulent isolate had naturally reassorted between a BLU-17 and BLU-10 isolate.

ISSN:0300-5526    

DOI:10.1159/000150551

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

We have measured markers of human papillomavirus type 16 (HPV 16) infection in children (1–10 years of age) who were hospitalized for reasons unrelated to papillomavirus infection. Genital and buccal swabs obtained from 79 children were tested for the presence of HPV 16 DNA by PCR. Low-level positivity was found in 34 donors, twice as often in oral than in genital swabs. There was no sex-specific difference, but there was a trend towards a higher positivity rate with young age. Serum antibodies (IgG) were measured by ELISA based on peptides derived from the HPV 16 early proteins E4 (one peptide), E6 (two peptides) or E7 (two peptides) in 75 children and by ELISA based on virus-like particles in 66 children. Low-positivity rates were found for E6 (5.1%), E7 (2.5%) or capsid proteins (1.5%), but 20.3% of the sera reacted with the E4-specific peptide. There was no correlation between sero-positivity and the detection of HPV 16 DNA. In those instances where HPV DNA positivity in young children represents true infection and not environmental contamination, we speculate that this infection is accompanied by low-level virus replication that does not induce a measurable antibody response. Reactivity to the E4 protein is likely due to cross-reacting antibodies directed either against E4 proteins of other HPV types or against unrelated antigen

ISSN:0300-5526    

DOI:10.1159/000150552

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

An efficient purification protocol for infectivity causing a transmissible spongiform encephalopathy (TSE) is described. From fractions purified by this protocol about 3 × 108 LD50 but only 3 ng of nucleic acids per gram of brain material can be isolated from all TSE-affected brains (hamster, human, sheep, cattle). By PAGE such fractions from brains of infected and control hamsters contained only one distinct nucleic acid band of 1.5 kb together with some broader smear of nucleic acid material. Although distilled water was used for such purifications, quite often a similar nucleic acid band was isolated from blanks containing no brain material. In all instances this material proved to be DNA. The result challenges the potentially important claim that purified infectious preparations of TSE-specific amyloid are free of nucleic acids of viral size. Nucleic acids isolated by other groups from diseased brain were not detected in preparations isolated by the new protocol. The application of this purification protocol in future studies will be helpful to decide whether TSEs are caused by agents containing nucleic acid or by protein only

ISSN:0300-5526    

DOI:10.1159/000150553

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

We report five cases of human disease caused by arbovirus in 5 patients from the State of São Paulo, Brazil, residing in the municipalities of Osasco, Atibaia, Guarujá, and the capital São Paulo, respectively. One of the patients resides in São Luis, capital of the State of Maranhão. The sites of infection probably were the states of Parana and Goiás, both in cave regions, the State of Amazonas, and Rondônia in two cases. Laboratory tests for malaria were negative and 1 patient showed a positive serum reaction for leptospirosis. Serum samples from the acute and convalescent phases were tested by hemagglutination inhibition, complement fixation, and neutralization in mice. Acute phase samples were inoculated into suckling mice by the intracerebral route. A close antigenic relationship was observed between the five agents isolated and the flavivirus Ilheus. Serologic tests demonstrated the absence of antibodies in all samples from the 5 patients during convalescence and even for more than 1 year after infection in 1 o

ISSN:0300-5526    

DOI:10.1159/000150554

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

As part of our efforts to develop bovine adenoviruses into a vector system, we sequenced the region predicted to encode the terminal protein precursor of either bovine adenoviruses type 2 and bovine adenoviruses type 3. We examined the regions containing the terminal protein precursors and showed that the bovine adenovirus early region 2B had an identical organization to all adenoviruses so far examined. The bovine adenovirus terminal protein precursors and those of other adenoviruses were also compared in a sequence alignment analysis and several highly conserved structural domains were identified. Finally, we showed how the various terminal protein precursors were related in a sequence pair similarity analysis and concluded that the terminal protein precursors of bovine adenoviruses types 2 and 3 are significantly different from each other at the protein sequence level.

ISSN:0300-5526    

DOI:10.1159/000150555

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The serum levels of the β-chemokine RANTES and, albeit less, MIP-1β were found to be increased in 37 HIV-1 infected compared to seronegative individuals. In contrast the serum levels of IL-16 were only sporadically elevated in seropositives as well as in seronegatives. Concomitantly, the RANTES gene expression increased about tenfold in seropositives, whereas the MIP-1β and IL-16 mRNA levels were not elevated. No correlation between the increase of the MlP-1β and RANTES serum concentrations and the plasma virus load, the number of the peripheral CD4+ T cells or the therapy status of the patients was found. However, the increased proportion of activated CD8+CD38+ T cells in the peripheral blood of all seropositives paralleled the increased RANTES serum levels detected indicating that immune activation in HIV-1-infected individuals may contribute to increased RANTES serum lev

ISSN:0300-5526    

DOI:10.1159/000150556

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Recombinant retroviral vectors that express the Env and Rev proteins of feline immunodeficiency virus (FIV) were prepared and analyzed in a mouse model system for their ability to induce antigen-specific CD8 + CTL (cytotoxic T lymphocyte) responses. The ultimate goal of these studies is to develop effective immunogens for CTL induction in the cat. Recombinant Env/Rev retroviral vectors were used to transduce mouse fibroblasts and these cells were then inoculated intraperitoneally into syngeneic BALB/c mice. FIV Env-specific CTL responses were obtained. The potent ability of recombinant retroviral vector-transduced cells to elicit cell-mediated immunity in the mouse model offers the possibility that such delivery systems may serve as therapeutic and/or prophylactic treatments against FIV infection in the cat.

ISSN:0300-5526    

DOI:10.1159/000150557

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Among patients undergoing maintenance hemodialysis, a high prevalence of hepatitis C virus (HCV) infection can be observed. In a prospective study, sera of 273 patients were examined for the presence of HCV infection by serological tests and by PCR. Thirty-five patients (12.8%) were HCV antibody positive, and in 31 of them HCV RNA could be detected by PCR. Among the 238 seronegative patients HCV infection was detected in 12 cases (5.0%) exclusively by PCR. Only in 1 of these patients seroconversion could be observed within the 18-month follow-up period. These findings demonstrate that in hemodialysis patients PCR is necessary for the diagnosis of HCV infection.

ISSN:0300-5526    

DOI:10.1159/000150558

出版商:S. Karger AG    

年代:1997

数据来源: Karger