Search PubMed⌕ Search

Biomedical subjects

V A Sundqvist

Publications and source records attributed to V A Sundqvist.

At least 19 recordsLinked to original sources
PubMed2000

Growth phenotypes of cytomegalovirus isolates do not correlate with glycoprotein B, major immediate early genotypes or antiviral sensitivity.

Human Cytomegalovirus (CMV) is generally described from in vitro experiments as a slowly replicating virus. A doubling time of one day in blood, however, has been shown in vivo. The growth phenotypes of CMV isolates and laboratory strains were studied in human fibroblasts. The viruses were found to replicate either rapidly or slowly. Comparison of CMV protein expression in lung and foreskin fibroblast cultures showed that two tissue culture adapted CMV strains (AD169 and Towne) and 3 clinical isolates belonged to the rapidly replicating viruses, whereas another 3 clinical isolates replicated slowly. CMV antigen concentrations were 6-fold and virus yields were 10-1000-fold higher for the rapidly replicating viruses than for the slow replicators. The antigen expression of two slowly replicating isolates was enhanced after 20 passages compared to the isolates at passage 5, but it was not as efficient as that of strain Towne. Slow or fast replication was related neither to major immediate early gene exon 4, and gB genotypes, nor to antiviral susceptibility. Proteins of the beta cascade may contribute to differences in the replication rate of CMV isolates.

Antiviral Agents↗
PubMed1998

Solid phase ELISA for determination of the virus dose dependent sensitivity of human cytomegalovirus to antiviral drugs in vitro.

The main problems in determining the true in vivo susceptibility of human cytomegalovirus (CMV) to antiviral compounds are the influence of the size of the viral inoculum, the variation in the replication capacity of different CMV strains and the subjective evaluation of the inhibition of viral growth in the plaque assay. In this study, a specific assay was developed which reproducibly determines the sensitivity of primary isolates of CMV. The assay includes simultaneous virus titration and determination of the antiviral sensitivity. When individual virus doses were evaluated, the IC50 was generally dependent on the virus dose, except for resistant isolates, where the IC50 did not change irrespective of the dose of virus. The novel method of IC50 calculation takes into account all values derived from the linear part of the inhibition curve. This may better reflect the in vivo conditions, where the antiviral drug encounters different amounts of virus in different organs. Two human fibroblast-derived cell lines showed similar results.

Antiviral Agents↗
PubMed1998

Infrequent detection of cytomegalovirus and Epstein-Barr virus DNA in synovial membrane of patients with rheumatoid arthritis.

OBJECTIVE: To study the role of the cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus types 1 and 2 (HSV-1 and 2), varicella zoster virus (VZV), and human herpes virus 6 (HHV-6) in the etiology of rheumatoid arthritis (RA). METHODS: Polymerase chain reaction (PCR) was used to detect DNA of the different herpes viruses in synovial membranes from 31 patients with chronic RA and 14 control patients. Specific antibodies were determined by indirect immunofluorescence and ELISA. RESULTS: Out of 31 patients with RA, CMV DNA was detected in synovial membranes from 2 patients and EBV DNA was detected in synovial membranes from 2 other patients. All samples from the patients with RA were negative for DNA from HSV-1 and 2, VZV, and HHV-6. All samples from the 14 control patients were negative in all PCR assays. No statistically significant differences in IgG antibodies were found for CMV, HSV-1, VZV, and HHV-6 in patients with RA compared to controls. Higher titers of IgG antibodies against EBV viral capsid antigen were found in patients with RA, with a significance of p < 0.05. CONCLUSION: Both CMV and EBV DNA were detected in synovial membranes from 6% of the patients with RA. We cannot exclude the possibility that these viruses were associated with disease development in a minority of patients with RA.

Adult↗
PubMed1997

Cytomegalovirus glycoprotein B-specific antibody analysis using electrochemiluminescence detection-based techniques.

An electrochemiluminescence technique was used to develop versatile and sensitive assay strategies for determination of seroreactivities against biologically important cytomegalovirus neutralization epitopes expressed on glycoprotein B. Indirect binding assays showed wide linear assay ranges and revealed that serum samples diluted in parallel with a monoclonal antibody-based standard, simplifying quantitative analytical assessments.

Antibodies, Viral↗
PubMed1995

Cytomegalovirus DNA in peripheral blood leukocytes and plasma from bone marrow transplant recipients.

Granulocytes, monocytes, and T- and B-lymphocytes were separated from 28 blood samples collected from 5 bone marrow transplant (BMT) recipients. About 40% of granulocyte, monocyte, and B-lymphocyte samples were CMV DNA-positive by polymerase chain reaction in recipients with cytomegalovirus (CMV) infection. CMV DNA was rarely detected in separated T-lymphocytes. Within each of the simultaneously separated paired samples, there were several with single positive cell subtypes. Monocytes, granulocytes, and B-lymphocytes were the single positive samples in some instances. Thus, it is important to have all of the different cell subtypes present in samples for detection of CMV DNA in peripheral blood. We also studied the appearance of CMV DNA in plasma and peripheral blood leukocytes (PBLs) from 351 blood samples collected from 30 BMT recipients during a follow-up period of at least 3 months after BMT. All cell subtypes were represented in the PBL samples. In the 13 recipients who developed symptoms possibly associated with CMV infection or CMV disease, a correlation with the detection of CMV DNA in < or = 2 x 10(5) PBLs was found. In PBLs from 11 of the 13 BMT recipients, CMV DNA was detected before the onset of symptoms. CMV DNA was not detected in < or = 2 x 10(5) PBLs from recipients without CMV infection. The virus load in PBLs decreased during ganciclovir treatment. Nine of the 13 recipients displayed PCR-positive plasma samples, and CMV DNA was detected frequently after the onset of symptoms.

Adolescent↗
PubMed1995

Human antibody reactivity against the lower matrix protein (pp65) produced by cytomegalovirus.

The lower matrix protein (pp65) is a major product of many laboratory strains of cytomegalovirus (CMV). It is thus an integral part of many CMV serological assays based on native antigen. Recombinant fragments of pp65 have previously been investigated for their usefulness in more-defined assays. The latter antigens have, however, failed to develop a positive response with serum samples derived from a substantial number of infected individuals. Here we show that the human humoral immune response to CMV pp65 is highly diverse and recognizes at least seven distinct but in some cases partly overlapping epitopes. Most of these epitopes could not be mimicked by any of the investigated recombinant or synthetic antigens. Furthermore, when we investigated the ability of human CMV-seropositive serum samples to block the reactivity of pp65-specific antibodies recognizing five different epitopes within pp65, it was evident that several sera did not contain significant levels of antibodies against any of these or overlapping structures. It was thus concluded that the antibody response against CMV pp65 is weak in some CMV-infected individuals, making this antigen unsuitable for use alone in serological screening systems for CMV infection.

Animals↗
PubMed1995

Enzyme-linked immunosorbent assay-based inhibition test for neutralizing antibodies to polioviruses as an alternative to the neutralization test in tissue culture.

A poliovirus-binding inhibition test (PoBI test) was established for the quantitative determination of antibodies to polioviruses and was evaluated in comparison with the conventional neutralization test (NT). The first step of the PoBI test is an incubation of serial dilutions of test samples with inactivated poliovirus followed by the detection of free viral epitopes by a double antibody sandwich enzyme-linked immunosorbent assay with type-specific capture polyclonal antisera and type-specific neutralizing monoclonal indicator antibodies. A comparison of the PoBI test with the conventional NT for antibodies to all three types in 100 human serum samples showed excellent correlations (r > 0.95) over a wide range of antibody concentrations. The PoBI test, not necessitating live virus and tissue culture facilities, could be a simple alternative to the NT, and the principle of the assay is potentially applicable to other microbial systems.

Animals↗
PubMed1994

HIV antigen-reactive T cells detected by antigen-induced interferon gamma secretion.

The T cell repertoire to human immunodeficiency virus (HIV) was studied in HIV-infected patients of different clinical stages by the detection and enumeration of cells that secreted interferon gamma (IFN-gamma) in short-term cultures of blood mononuclear cells after stimulation in vitro with the HIV recombinant antigens pB1, p121, p24-15, gp160bac, and the HIV V3 loop peptide. T cell reactivities to cytomegalovirus (CMV) and Mycobacterium tuberculosis-purified protein derivative (PPD) were examined in parallel. Among 29 patients with HIV infection, 48% had blood cells recognizing one or more of the five HIV antigens. The mean numbers of HIV antigen-reactive T cells varied between 1/approximately 6000 blood cells for pB1 and 1/approximately 20,000 cells for p24-15. None of the five HIV antigens studied was identified as an immunodominant T cell epitope in HIV infection. T cells from 20% of the patients responded to all five HIV antigens in parallel, but the antigen preferentially recognized varied from patient to patient. Those with more advanced disease had a tendency to lower numbers of HIV antigen-reactive T cells. Most HIV-infected patients had both CMV- and PPD-reactive T cells, but numbers were significantly lower in more advanced disease. It should be possible to adopt the present method to evaluate fine specificities of the T cell repertoire to other antigens and to study the involvement of other cytokines besides IFN-gamma, for example, the Th2 cell-related cytokine interleukin 4.

Adult↗
PubMed1994

Presence of autologous neutralizing antibodies against cytomegalovirus (CMV) in serum of human immunodeficiency virus type 1-infected patients shedding CMV in saliva.

This study evaluated whether cytomegalovirus (CMV) neutralizing capacity affected shedding of CMV in saliva in human immunodeficiency virus type 1 (HIV-1)-infected patients and mapped specific epitope reactivity of CMV IgG antibodies. Total CMV IgG titers were significantly higher in symptomatic than in asymptomatic HIV-1-infected patients or controls. All CMV-seropositive patients had neutralizing antibodies to CMV. Shedding of CMV in the saliva of AIDS patients occurs despite the presence of serum antibodies with a high capacity to neutralize autologous CMV isolates. The highest IgG reactivity against a CMV envelope protein (gp116), represented by a peptide, was found in patients with advanced HIV disease. In contrast, identical IgG reactivities against a peptide representing the CMV matrix protein were observed in healthy controls and HIV-1-infected persons.

Adult↗
PubMed1993

T and B cell responses to cytomegalovirus antigens in healthy blood donors and bone marrow transplant recipients.

We measured the production of interferon-gamma (IFN-gamma) from single T cells and the T cell proliferative response to different cytomegalovirus (CMV) antigens in healthy blood donors and bone marrow transplant recipients. The antigens consisted of a CMV nuclear antigen (CMV na) containing the pp65-kDa matrix protein and the immediate early antigens but lacking CMV glycoproteins, and an antigen comprising native CMV glycoproteins (CMV gp). We also measured the IgG antibodies to CMV na and CMV gp. The T cells reacted to CMV na in CMV seropositive blood donors both with the production of IFN-gamma and with proliferation, while bone marrow transplant recipients had a deficient T cell response. After stimulation with CMV gp, no T cell response could be observed in CMV seropositive subjects. IgG antibodies to CMV na coexisted in plasma with similar levels of antibodies to CMV gp.

Adolescent↗
PubMed1993

Fine specificity of the human immune response to the major neutralization epitopes expressed on cytomegalovirus gp58/116 (gB), as determined with human monoclonal antibodies.

The humoral immune response to human cytomegalovirus (CMV) membrane glycoprotein gp58/116 (gB) has been studied by establishing cell lines producing specific human monoclonal antibodies. These cell lines were generated from peripheral blood lymphocytes obtained from a healthy carrier. Hybridomas producing gp58/116-specific antibodies were detected by reactivity to procaryotically expressed proteins containing the major neutralizing epitopes of this glycoprotein complex. One antibody, ITC88, which recognized an epitope located between amino acid residues 67 and 86 of gp116, potently neutralized the virus at 1 to 2 micrograms of immunoglobulin G per ml. Only four of the six human antibodies detecting the major neutralizing domain of gp58 neutralized the virus, and none of them required complement for activity. All antibodies that bound mature, processed gp58 recognized a conformational epitope involving sequences between residues 549 and 635. However, small differences existed between the antibodies in the actual minimal requirement for C- and N-terminal parts of this epitope. By peptide mapping with several of the antibodies, the epitope was shown to consist mainly of residues between amino acids 570 to 579 and 606 to 619. Despite the conformational nature of the epitope, the antibodies recognized both reduced and denatured native antigen. Presence of carbohydrates was not required for antigen binding of these gp58-specific human antibodies, but in at least one case, it greatly enhanced antigen recognition, indicating an importance of carbohydrate structures in some epitopes within the major neutralizing specificity of gp58.

Antibodies, Monoclonal↗
PubMed1993

Diagnosis of cytomegalovirus infections using polymerase chain reaction, virus isolation and serology.

The nested Polymerase Chain Reaction (PCR) was compared with virus isolation and serology to establish which is the best method for the diagnosis of active cytomegalovirus, (CMV) infection. Samples of blood leucocytes, urine and throat washings from immunosuppressed patients and patients with congenitally acquired CMV infection, as well as from healthy persons, were examined with PCR. CMV DNA was detected in all samples from which CMV could be isolated, but not from any sample from healthy adults, whether CMV seropositive or CMV seronegative. In contrast to the findings in healthy persons, CMV genomes were frequently detected in urine and throat washings from immunosuppressed, CMV-seropositive patients without symptoms of CMV infection. The appearance of CMV genomes in blood cells in immunosuppressed CMV-seronegative patients may be the first sign of primary CMV infection. Congenital CMV infection could be rapidly and safely diagnosed when urine samples were examined by PCR. Nested PCR is a valuable tool for the diagnosis of active CMV infection, when selected materials are used.

Adolescent↗
PubMed1992

Cytomegalovirus infection of the central nervous system in patients with AIDS: diagnosis by DNA amplification from cerebrospinal fluid.

A nested polymerase chain reaction (PCR) was evaluated for the detection of cytomegalovirus (CMV) DNA in cerebrospinal fluid (CSF). CSF and serum samples from 19 AIDS patients with intracerebral CMV infection diagnosed at autopsy were retrospectively examined. As controls, CSF and serum samples from 15 AIDS patients with only extracerebral CMV involvement at autopsy, from 10 AIDS patients without CMV infection at autopsy, and from 10 anti-human immunodeficiency virus-negative patients without ongoing CMV infection, were studied. CMV DNA was detected from patients with intracerebral CMV infection in 9 of 9, 5 of 6, and 1 of 4 CSF samples collected, respectively, 1-30, 30-90, and 90-300 days before death. Twelve of 13 sera from these patients were CMV PCR-positive. None of the control patients had CMV DNA in CSF. PCR was positive in 6 of 8 sera from AIDS patients with only extracerebral CMV infection and in serum from 1 AIDS patient without CMV involvement at autopsy. CMV PCR on CSF is highly sensitive and specific. It should be considered a rapid and reliable diagnostic method for CMV infection of the central nervous system.

AIDS-Related Opportunistic Infections↗
PubMed1992

Glycoprotein gp116 of human cytomegalovirus contains epitopes for strain-common and strain-specific antibodies.

Glycoprotein gp116 of human cytomegalovirus (HCMV) is a target for neutralizing antibodies. Gp116 is a component of the gCI complex which consists of gp58 and gp116. Like its homologue, glycoprotein B of herpes simplex virus type 1, gp116 contains a highly antigenic region in the N-terminal part of the molecule, between amino acids 28 and 84. Prokaryotic expression plasmids and synthetic peptides were used to define binding sites for mouse and human monoclonal antibodies (MAbs) as well as HCMV convalescent sera. Site I, located between amino acids 68 and 77, contains an epitope recognized by the human MAb C23, which is capable of neutralizing HCMV independently of complement and the site is conserved between HCMV strains. Of HCMV-positive human sera, 53% recognized site I. Site II was mapped using mouse MAbs as well as human sera. It is located between residues 50 and 54, an area which is not conserved between strains AD169 and Towne, the two laboratory strains of known sequence. Strain-specific antibodies were detected in 25% of human sera. Site II-specific antibodies, purified from human sera by affinity chromatography, were found to be incapable of neutralizing HCMV in tissue culture.

Amino Acid Sequence↗
PubMed1992

Antibody responses to synthetic peptides from cytomegalovirus phosphoprotein 150.

We have identified antigenic regions within phosphoprotein 150 of human cytomegalovirus (CMV pp150) to which seroreactivity appears in patients with active CMV infection or persists in seropositive persons. A range of 8.3 to 61.6% of healthy CMV-seropositive blood donors were immunoglobulin G positive for single peptides, while 91.6% reacted to a mixture of four peptides. All convalescent-phase serum samples from 26 patients with active CMV infection reacted with either of two peptides encompassing amino acids (aa) 594 to 623 and aa 614 to 643. Patients with a primary CMV infection had patterns of reactivity to single peptides different from those of patients with reactivated CMV infection. The immunoglobulin M antibodies reacted preferentially with the peptides encompassing aa 594 to 663 of CMV pp150.

Amino Acid Sequence↗
PubMed1992

Variations in the cytomegalovirus major immediate-early gene found by direct genomic sequencing.

An assay to detect and sequence DNA from human cytomegalovirus (HCMV) immediate-early gene region 1 has been developed; it involves in vitro amplification by the polymerase chain reaction and direct solid-phase sequencing of the amplified material. Urine samples from 16 patients tested positive for HCMV DNA in both a colorimetric assay for the detection of immobilized amplified nucleic acids and a standard polymerase chain reaction assay with agarose gel electrophoresis. Ten urine samples from healthy people tested negative in the same assays. Analysis of 106-bp fragments from seven patients and two laboratory HCMV strains (Ad 169 and Towne) demonstrated that the viral sequences were conserved in samples collected at different times from the same patient and in tissue-cultured samples. Two of the patient strains had variations in the amplified region, with a total of seven nucleotide substitutions yielding five amino acid alterations in the coding sequence.

Amino Acid Sequence↗
PubMed1992

Cytomegalovirus DNA detection in sera from patients with active cytomegalovirus infections.

Using a specific and sensitive polymerase chain reaction method, we detected reliably the presence of human cytomegalovirus (HCMV) DNA directly in serum samples collected at an early stage of HCMV infection, even before immunoglobulin M (IgM) antibodies were measurable. HCMV DNA was detected in serum from all patients with active HCMV infection; in 91% of these patients, HCMV DNA was found in the acute-phase serum. In 13 of 44 patients, HCMV DNA was found in serum before HCMV-specific IgM. For four kidney transplant recipients, the occurrence of HCMV DNA in serum, virus isolation from urine and leukocytes, and HCMV IgG and IgM serology were determined. We found a correlation between HCMV DNA in serum and positive virus isolation from leukocytes. In three of five congenitally infected infants, HCMV DNA and HCMV IgM were detected in the same sample. Two other infants were HCMV DNA positive, although no HCMV IgM antibodies were measurable. HCMV was found in urine from these infants either by virus isolation or with the polymerase chain reaction. Serum from one of the 22 healthy HCMV-seropositive blood donors was HCMV polymerase chain reaction positive.

Antibodies, Viral↗