Biomedical subjects

H T Agostini

Publications and source records attributed to H T Agostini.

29 records · Page 2Linked to original sources

PubMed1997

JC virus regulatory region rearrangements and genotypes in progressive multifocal leukoencephalopathy: two independent aspects of virus variation.

JC virus (JCV) causes the central demyelinating disease progressive multifocal leukoencephalopathy (PML). JCV strains excreted in the urine are distinguishable from those in PML tissue by the configuration of their regulatory region to the right of ori: the archetypal regulatory region, 267 nucleotides long, is rearranged in PML tissue by deletion and duplication. Within the coding region JCV shows variations as a result of virus evolution. Four major genotypes are distinguishable of which Type 1 is based in Europe and Type 2 in Asia. Here, the regulatory region rearrangements and the viral genotypes of 29 JCV strains from PML brain were determined. Rearrangement patterns and genotypes were not associated. In general, deletions occurred before duplications, but exceptions to this rule exist. Each configuration of the 29 rearranged regulatory regions was unique and could be derived directly from the non-rearranged, archetypal form.

Gene Rearrangement↗

PubMed1996

Genotype profile of human polyomavirus JC excreted in urine of immunocompetent individuals.

The human polyomavirus JC (JCV) causes the central demyelinating disease progressive multifocal leukoencephalopathy in about 5% of AIDS patients. To characterize the type profile of JCV in a control population in the United States, 54 females (10 to 79 years of age; average age, 43.4 years) and 51 males (18 to 94 years of age; average age, 47.9 years) were examined for the excretion of different genotypes of JCV in their urine by PCR followed by direct cycle sequencing. The group consisted of 89 patients of a general medical clinic in addition to 16 healthy volunteers. The overall incidence of JC viruria was 43 of 105 (40.9%) subjects, with a marked increase for those subjects above the age of 30 years. Two men were found to excrete two different types of JCV at the same time, indicating double infections. Of the three different genotypes of JCV identified to date, type 1 strains (European) were the most common in this cohort (64% of total strains) followed by type 2 (East Asian) (18%). No type 3 (East African) strains were detected. Indirect evidence for the existence of JCV type 3 was found in seven individuals (16%) in the form of a type 1/3 recombinant (also called type 4). In addition, a single example of JCV which differs from types 1, 2, and 3 and may represent a phylogenetically older type (type 5) was found in a 59-year-old African-American. Delineation of sequence variations between JCV types is essential for the design of primers for sensitive PCR with clinical samples.

AIDS-Related Opportunistic Infections↗

PubMed1996

Co-infection with two JC virus genotypes in brain, cerebrospinal fluid or urinary tract detected by direct cycle sequencing of PCR products.

The human polyomavirus JC (JCV), which exists in different geographically based genotypes, causes the central demyelinating disease known as progressive multifocal leukoencephalopathy (PML). A coding region recombinant JCV Type 1/Type 3 (Type 4) is excreted in the urine of some 16% of individuals in the USA. In addition, occasional 'crossovers' in viral DNA sequence at type-specific sites in the coding region occur between JCV genotypes amplified from PML brain. For recombination to occur requires the existence of two different genotypes in the same host. Here we provide evidence from direct cycle sequencing of PCR products that different genotypes of JCV can be found in a single tissue sample. After non-type-specific PCR amplification, cycle sequencing produced 'split bands' at type determining sites which were resolved into type or subtype-specific sequences by subcloning of the PCR products. PCR products with split bands at typing sites were found in two brain samples and in one cerebrospinal fluid (CSF) from AIDS patients with PML and in the urine of four immunocompetent individuals. This indicates that co-infection with two viral types does not depend on severe immunocompromise. Combinations of genotypes found were Types 1A & 1B, 1A & 2, 1B & 2 and 2 & 3. In one doubly infected patient the major JCV type excreted in the urine changed within 1 week.

Adult↗

PubMed1996

Characterization of JC virus DNA amplified from urine of chronic progressive multiple sclerosis patients.

Thirty-seven chronic progressive multiple sclerosis (MS) patients, 20 of whom were taking cyclosporine, were examined for excretion of JC virus (JCV) in the urine. Polymerase chain reaction (PCR) amplification of DNA in urinary cell extracts detected JCV in 30% of the MS urines. In the cyclosporine treated group four of 20 (20%) excreted JCV, whereas in the untreated group seven of 17 (41%) excreted JCV. Thus, cyclosporine treatment did not enhance urinary excretion of the virus. A control group consisting of an unselected series of 89 patients donating urine in a general medical clinic and 16 healthy volunteers showed 41% with detectable urinary JCV. Thirty-three percent of the control females excreted JCV (18/54), as did 49% of the control males (25/51). Although the percentage of MS patients excreting detectable virus was not increased compared to the control group, the presence of JCV in the urine provides a convenient source of the virus for further characterization. Genotyping of DNA fragments amplified from the VP1 region indicates mainly the presence of JCV Type 1 in these chronic progressive MS patients. This is also the type that predominates in the control group. An apparent recombinant between Type 1 and Type 3 (African) within the VP1 region, tentatively designated Type 1/3 (or Type 4), was found in both the MS group and the controls. A larger series of MS patients that includes relapsing/remitting disease will be required to determine whether the genotype profile of JCV excreted in the urine of MS patients differs significantly from controls.

Adult↗

PubMed1995

BK virus and a new type of JC virus excreted by HIV-1 positive patients in rural Tanzania.

HIV-1 positive patients from Tanzanian villages near Shirati were examined for urinary excretion of the human polyomaviruses JC and BK using the polymerase chain reaction (PCR). BK virus (BKV) was detected in 11 of 23 individuals tested. The BKV DNA sequences were all closely related to prototype Gardner strain and BKV (DUN). In contrast, a new type of JCV, termed Type 3 [or JCV (Shi)], was identified in seven of these same 23 individuals by comparison with Type 1 and Type 2 sequences of the VP1/intergenic/T antigen region of U.S., European and Asian strains. This suggests that JCV and BKV, although closely related, have different evolutionary histories within the African population. The six BKV regulatory regions amplified all showed the archetypal configuration. However, two of the seven JCV regulatory regions showed rearrangements: a small deletion and an inverted repeat. JCV causes a fatal demyelinating disease, progressive multifocal leukoencephalopathy (PML), in about 5% of AIDS patients in Europe and the U.S.A., but only one case has been reported in Africa. Our results suggest that this rarity of PML is not due to the absence of JCV in the African population.

Adolescent↗

PubMed1995

Monospecific polyclonal anti-anti-idiotypic antibodies to the carboxyterminal undecapeptide of the SV40 large tumour antigen.

The murine monoclonal antibody PAb1605 defines an epitope, peptide Lys(698)-Thr(708) (KT), on the carboxyterminus of the tumour(T)antigen of SV40-transformed cells. In vivo and in vitro experiments had shown that this sequence represents an epitope for both humoral and cellular immune responses. When injected into rabbits PAb1605 induces anti-idiotypic antibodies (Ab-2). Ab-2 beta (internal image type) was purified by adsorption chromatography and characterized by the ability of KT to compete with the binding of ab-2 with ab-1. Murine anti-anti-idiotypic antibodies (ab-3) were obtained by immunization of mice with ab-2 beta. Both ab-1 and ab-3 JgG showed affinities to immunoprecipitated SV40 T antigen by immunoblot analysis and to nuclear SV40 T antigen by the immunofluorescence assay. The binding of ab-3 to SV40 T antigen was completely inhibited by competition with KT. We conclude that the polyclonal ab-3 is of the ab-3 subtype and specific for only one epitope which is represented by KT and defined by ab-1. The results demonstrate that the specificity for a defined peptide epitope of an antibody was conserved even after two consecutive steps of anti-idiotypic-antibody formation in two host species. Since this postulate of network theory could be verified for a sequence of a tumour-associated antigen which represents a B- and T cell epitope, this model is of great interest for further tumour immunological studies.

Amino Acid Sequence↗

PubMed1995

Subretinal tumour in a patient with a limited form of Wegener's granulomatosis.

In 1939 F. Wegener published a report concerning a peculiar febrile syndrome with necrotizing inflammation of the upper respiratory tract, focal glomerulonephritis and systemic angiitis (Wegener 1939). Clinically Wegener's granulomatosis can be divided into a limited and a generalized form. We describe a patient presenting with unilateral ocular symptoms suspicious of a neoplasm, one episode of angina pectoris and general malaise without any clinical signs of upper respiratory tract involvement. Before Wegener's granulomatosis was diagnosed by a positive titre of antineutrophil cytoplasmic antibodies and open lung biopsy, immunoscintigraphy for malignant melanoma showed a false positive result. Systemic treatment with corticosteroids and cyclophosphamide resulted in an improvement of the ocular symptoms within weeks.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1995

Amplification of the complete polyomavirus JC genome from brain, cerebrospinal fluid and urine using pre-PCR restriction enzyme digestion.

A method is described for amplification of the complete genome of the human polyomavirus JC (JCV) from progressive multifocal leukuencephalopathy (PML) brain, cerebrospinal fluid (CSF) of PML patients, and from the urine of controls without neurological disease. Efficient amplification with the 'long PCR' method is achieved with primers overlapping the single BamHI or EcoRI site following digestion of the DNA sample with the restriction enzyme BamHI or EcoRI, respectively. Cutting of the supercoiled JCV genome allows full separation of the strands during the denaturation step, and permits primer annealing to compete successfully with reassociation of the genomic DNA. With this method a single PCR amplification allows restriction fragment length polymorphism (RFLP) analysis and direct cycle sequencing of any part of the viral genome. RFLP analysis of JCV amplified from CSF has identified a new mutant sequence. Sequencing of clinical samples is useful for typing of JC virus isolates as Type 1 or Type 2 and for characterization of the JCV regulatory region as archetypal or rearranged.

Base Sequence↗

PubMedDate not supplied

Rearrangements of archetypal regulatory regions in JC virus genomes from urine.

The regulatory region of progressive multifocal leukoencephalopathy-type JC virus (JCV) is rearranged in each host by a process of deletion and duplication. Of the more than 40 that have been examined, no two regulatory regions have been rearranged identically in the brain. The substrate for this rearrangement appears to be a highly stable archetypal regulatory region excreted in the urine. Its role as the transmissible form of the virus, although inferred, has never been proven. We have now amplified by PCR and cycle-sequenced the regulatory regions from 48 urinary strains of the virus. We find that the urinary form of the regulatory region is not entirely stable. Short deletions and duplications in the range of 2-16 bp were observed in seven of these strains. One of these, an inverted repeat, is a pattern of rearrangement not yet found in the brain. Two others (#208 and 230) showed a 2-bp deletion at position nos. 221 and 222, and an unusual mutation at position no. 219. These two urines were collected in different states of the USA at different times and analysed months apart. It is very unlikely that these unusual changes represent sample contamination or that they arose independently. This finding indicates that archetypal forms of the JCV regulatory region are infectious, despite their relative inactivity in tissue culture. While changes in the archetypal structure can be found, it is clear that rearrangements in the kidney are rare or rarely infectious.

Adult↗

PubMedDate not supplied

JC virus type 2B is found more frequently in brain tissue of progressive multifocal leukoencephalopathy patients than in urine from controls.

OBJECTIVES: Previous studies have shown that strains of human polyomavirus JC (JCV) of Asian origin (type 2) are much more highly represented in progressive multifocal leukoencephalopathy (PML) brain than would be expected from their frequency of excretion in urine samples of a comparable control group. The present studies were designed to test whether one subtype of type 2 was preferentially elevated. STUDY DESIGN/METHODS: The statistical relation between JCV subtypes represented in PML brain tissue from 51 probands and those in urine samples from 115 control individuals was examined. RESULTS: The proportion of the JCV subtype 2B in PML brain (36%) was highly significantly increased relative to its occurrence in control urine samples (5.9%; P < .001). Type 1 and its subtypes were not different in the PML brain and control urine cohorts. The number of type 4 strains in PML brains was reduced, although the difference did not reach statistical significance (P = .08). CONCLUSIONS: The results predict that the human immunodeficiency virus (HIV)-positive individuals at highest risk of PML infection are those carrying the JCV genotype known as type 2B. Prospective studies will be required to confirm this finding.

Adult↗

PubMedDate not supplied

Complete genome of a JC virus genotype type 6 from the brain of an African American with progressive multifocal leukoencephalopathy.

OBJECTIVES: The major genotypes of the human polyomavirus JC (JCV) include type 1 (European), type 2 (Asian), type 3 (African), and type 4 (United States). Here we report characterization of the complete genome of a genotype obtained from the brain of an African American with systemic lupus erythematosus (SLE) and progressive multifocal leukoencephalopathy (PML). STUDY DESIGN/METHODS: DNA extracted from JCV-infected brain tissue was subjected to whole-genome polymerase chain reaction (PCR) amplification and direct cycle sequencing. Relations to other JCV genotypes and the predicted amino acid sequence were analyzed. RESULTS: This African-American type 6 strain (#601) differs from strains of all other genotypes in about 2% of its DNA sequence. The length of the total coding region of strain #601 is increased to 4855 bp by the insertion of a single nucleotide in the large T-antigen intron. This strain, originally placed with the type 2 group on the basis of its sequence in the VT-intergenic region, is very closely related to strains recently identified in the urine of individuals from Ghana, West Africa. CONCLUSIONS: This is the first example of an African JCV genotype identified in the brain of an African-American PML patient. The extent of sequence divergence of JCV type 6 suggests a split of type 6 strains before the separation of types 2 and 3. These findings confirm that distinctive African genotypes of JCV have been maintained in the African-American population and that they are capable of causing PML.

Adult↗