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Biomedical subjects

G Jahn

Publications and source records attributed to G Jahn.

At least 91 records · Page 5Linked to original sources
PubMed1993

Herpesvirus saimiri transformed human T cell lines: a permissive system for human immunodeficiency viruses.

Human peripheral blood T lymphocytes are readily transformed to continuous growth by Herpesvirus saimiri subgroup C strains. The immortalized cells express the phenotype of mature activated T cells and bear either CD4 or CD8 surface markers. Here we report that Herpesvirus saimiri transformed CD4+ cell lines are highly susceptible to infection with human immunodeficiency viruses types 1 and 2. The prototype viruses HIV-1IIIB and HIV-2ROD replicated rapidly and caused cell death within 14 days. These cell lines did also support growth of a poorly replicating HIV-2 strain (HIV-2NEP) and of primary clinical isolates. Thus H. saimiri transformed T cells represent a new system for HIV propagation and isolation, especially for HIV-2 strains with restricted cell tropism. These cells should be considered as an alternative approach in cases where conventional attempts fail.

Cell Line, Transformed↗
PubMed1993

Cell types infected in human cytomegalovirus placentitis identified by immunohistochemical double staining.

Chronic villitis is almost always present in intrauterine infection with human cytomegalovirus (HCMV). The inflammatory response to this virus has been described in detail. However, little is known about the types of placental cells that may be infected by HCMV and six cases of HCMV placentitis were thus investigated to identify the vulnerable cell types. Immunohistochemical double staining analyses were performed using antibodies to HCMV immediate early antigens and to specific cellular marker proteins. Fixed connective tissue cells could be demonstrated to be the predominantly infected cell type in each placental tissue. Endothelial cells and macrophages were also found to be infected in all six cases, whereas evidence of trophoblast infection was obtained in four cases. It is concluded that release of infectious virus by connective tissue cells, macrophages and endothelial cells may play a critical role in transplacental transmission of HCMV. The findings further suggest that the cytopathic effect of HCMV infection on these cells might be involved in the pathogenesis of intrauterine HCMV disease.

Antigens, Viral↗
PubMed1993

Molecular and biological characteristics of a novel HIV-2 isolate, HIV-2HOM.

In 1991 a new HIV-2 isolate (HIV-2HOM) was isolated first from a German individual most likely infected in West Africa in the beginning of the 1970s. The virus was isolated from both, the plasma and the peripheral blood lymphocytes of the patient by using OKT-3-stimulated cord blood lymphocytes. The recovered viruses could be further propagated on Jurkat cells and exhibited a broad cell tropism. Biochemical and antigenic properties of HIV-2HOM were examined by radioimmunoprecipitations. For a more detailed molecular characterization, a 1520 bp DNA fragment from the env gene and a 722 bp DNA fragment from the pol gene were amplified by polymerase chain reactions, cloned and sequenced. A comparison of both sequences to prototypic HIV-2 and SIV isolates revealed a close relationship to HIV-2ST. This strain originated from an asymptomatic Senegalese individual and is supposed to be of reduced pathogenicity. Taking into account genetic data, it may be assumed that HIV-2HOM and HIV-2ST are closely related strains with different growth characteristics and pathogenic features.

Base Sequence↗
PubMed1993

Immunohistochemical detection of viral antigens in smooth muscle, stromal, and epithelial cells from acute human cytomegalovirus gastritis.

To analyze the expression of different human cytomegalovirus (HCMV) antigens in gastric biopsy samples from a renal transplant recipient suffering from HCMV gastritis, monoclonal antibodies (MAbs) were used in immunohistochemical analyses. In samples obtained before the start of specific therapy with ganciclovir, MAbs against immediate-early (E13), early (CCH2), and late antigen (XP1) reacted with cells in the smooth muscle, stromal, and epithelial layers. MAb E13 stained morphologically altered and unaltered cells; MAbs CCH2 and XP1 predominantly stained cytomegalic cells. After therapy with ganciclovir was begun, the three viral antigens were almost exclusively found in the epithelial cell layer, whereas viral antigen appeared to be cleared from smooth muscle and stromal cells. All cells stained by MAb E13 in these samples showed characteristic morphologic alterations, in contrast to cells in earlier samples. The changes in the pattern of viral antigen expression may reflect the effects of antiviral therapy.

Acute Disease↗
PubMed1993

Detection of varicella zoster virus DNA and viral antigen in human cornea after herpes zoster ophthalmicus.

This article describes the histopathology, immunohistochemistry, and varicella zoster virus DNA in situ hybridization of 14 corneal buttons obtained from 14 patients (average age 69.0 years) after perforating keratoplasty (four patients) or surgical enucleation (10 patients) at different times after the clinical onset of herpes zoster ophthalmicus (average 58.7 months). The main histopathologic features were intense stromal vascular scarring (12 patients) and granulomatous reaction to Descemet's membrane (nine patients). Using the peroxidase-antiperoxidase method, varicella zoster virus (VZV) antigen could be detected by immunohistochemistry in two patients within epithelial cells of the cornea and in the limbal episclera during the active phase of herpes zoster ophthalmicus. For in situ hybridization we used the 35S-labeled HindIII A and C fragment of VZV and identified viral DNA in five corneal buttons obtained 1 day to 8 years after the clinical onset of infection. Viral DNA was mainly found in mononuclear cells with eosinophilic intracytoplasmic inclusions within vascular stromal scars, in keratocytes, and in epithelial cells of the cornea. Our results show that VZV DNA is detectable in human cornea even 8 years after the clinical onset of herpes zoster ophthalmicus and may indicate VZV persistence in a latent form in corneal tissue or reactivation of the virus from an endogenous or exogenous source causing a severe and often recurrent keratitis in the progress of herpes zoster ophthalmicus.

Adult↗
PubMed1993

Diagnostics of persistent viruses: human cytomegalovirus as an example.

Infections with persistent viruses such as herpesviruses have become of significant clinical importance with the increasing number of immunocompromised patients at risk to suffer from severe disease. As antiviral chemotherapy is available for herpesvirus infections, the diagnostic methods for rapid and sensitive detection of symptomatic infection have been developed and recently refined. In human cytomegalovirus (HCMV), the use of recombinant viral antigens provides a rationale to improve serological assays. This may be of use for the discrimination of primary versus secondary infection. Early diagnosis of symptomatic HCMV infection in immunosuppressed patients can be most effectively achieved by the detection of a viral tegument protein, pp65, in peripheral blood leukocytes. This early diagnosis has been shown to be of major importance for the effective treatment of these patients. HCMV infection in solid organs can be demonstrated by immunohistochemistry using monoclonal antibodies against viral proteins. HCMV involvement in diseases of the central nervous system in AIDS patients can be verified by the detection of very small amounts of HCMV DNA in cerebrospinal fluid by polymerase chain reaction. This method may prove useful for monitoring HCMV encephalitis and neuropathy.

AIDS-Related Opportunistic Infections↗
PubMed1992

Detection of varicella zoster virus DNA and viral antigen in the late stage of bilateral acute retinal necrosis syndrome.

We describe the clinicopathologic and virologic findings in the right, blind eye of an immunocompetent 61-year-old woman. The eye was enucleated 32 months after the clinical onset of a bilateral acute retinal necrosis syndrome. Histopathologic study showed a diffuse, full-thickness, necrotizing retinitis with replacement of sensory retinal structures by glial tissue, occlusive retinal arteritis, granulomatous choroiditis, and optic neuritis with ischemic optic atrophy. Varicella zoster virus could be identified as the causative agent by DNA in situ hybridization and by immunohistochemical stains in mononuclear cells with eosinophilic intracytoplasmic inclusions. Virus was detected only within the choroid and the choriocapillaris. We conclude that these histopathologic and virologic features are consistent with a "burned-out phase" of a varicella zoster virus-induced acute retinal necrosis syndrome.

Antigens, Viral↗
PubMed1992

Early diagnosis and successful treatment of acute cytomegalovirus encephalitis in a renal transplant recipient.

We report the case of a 40-year-old male HIV-negative renal transplant patient with allograft rejection and immunosuppressive therapy who presented with acute cytomegalovirus (CMV) encephalitis. CT and MRI of the brain were normal but EEG showed diffuse slowing and dysrhythmia. In cerebrospinal fluid (CSF) initially 81 cells/microliters were found and immunocytochemistry showed a decreased CD4/CD8 ratio and increased values of activated lymphocytes, natural killer cells and immunoglobulin-containing cells. CMV-specific IgM antibodies in CSF and serum, immunostaining of CMV antigen in CSF cells and virus culture from CSF and urine were negative. During the first 3 weeks of illness no intrathecal production of immunoglobulins could be detected. Early diagnosis of CMV encephalitis was made by in situ hybridization (ISH) on CSF cell preparations and the polymerase chain reaction (PCR) which was positive in CSF and blood. On day 26 diagnosis was confirmed by detection of CMV-specific intrathecal IgG production. The patient was treated with ganciclovir, anti-CMV immunoglobulins and intrathecal beta interferon. He recovered completely after 2 months. Our data demonstrate the usefulness of ISH and PCR in the early diagnosis of CMV encephalitis and perhaps may encourage the use of intrathecal beta interferon in other patients with this disease.

Acute Disease↗
PubMed1992

The DNA-binding protein P52 of human cytomegalovirus reacts with monoclonal antibody CCH2 and associates with the nuclear membrane at late times after infection.

Monoclonal antibody CCH2 is commonly used for the detection of human cytomegalovirus (HCMV) infected cells in tissue sections as well as in cultured cells. The specificity of CCH2 was determined by screening a recombinant lambda-gt11 cDNA gene bank from HCMV-infected fibroblasts. By sequencing a reactive clone, the antigen was identified to be the non-structural DNA binding protein p52 of HCMV (UL44 reading frame). The viral insert from the lambda clone was recloned in bacterial expression vectors. For this, a new vector, pRos-RS, was constructed. The resulting clones were tested in immunoblot analyses. They were reactive with CCH2 as well as with reconvalescent sera positive for antibodies against HCMV, by this proving the specificity of CCH2. Using this monoclonal antibody in confocal microscopy, the subcellular localization of p52 in infected cells was analyzed. In these analyses, p52 was found to be nuclear and to be associated with the nuclear membrane at late times after infection.

Amino Acid Sequence↗
PubMed1992

Antibodies against p24 of HIV-1 in patients with systemic lupus erythematosus?

The involvement of retroviruses in the etiopathogenesis of autoimmunity is discussed. Recently antibodies against p24 of HIV-1 were described in patients from Texas with SLE. Therefore we investigated the presence of these antibodies in our SLE collective (German caucasians and blacks from Michigan) employing ELISA and Western blot. No anti-p24 reactivity was observed in our SLE patients in Western blots, suggesting that there may be ethnological or regional differences between our patients those from Texas.

AIDS-Related Complex↗
PubMed1992

Viral culture and p24 antigenemia of human immunodeficiency virus (HIV)-infected individuals correlated with antibody profiles determined with recombinant polypeptides of all HIV-1 open-reading frames.

The association between viral activity and antibody profiles was investigated in 202 individuals infected by the human immunodeficiency virus (HIV) grouped according to their Walter Reed clinical stage. Each study group was subdivided into subjects positive or negative for markers of active viral replication: presence of serum p24 antigen and viral culture. In Western blots using recombinant antigens, sera of HIV-positive individuals with positive viral markers had a significantly lower antibody reactivity to several viral proteins than did individuals without viral markers. Noticeably, proteins of the gag (p24, p17) and env (gp120, COOH-terminal part of gp41) open-reading frames revealed a decreased reactivity. The antibody response to the regulatory proteins revealed no or poor association with viral activity in the host. The results suggest that seroreactivity is mainly influenced by factors reflecting the viral activity of an HIV-infected individual, while the clinical stage of the patient is less important. Especially, reductions in antibodies against gp120 and p17 were useful markers associated with increased viral activity.

Adult↗
PubMed1992

Monoclonal antibody E-13 (M-810) to human cytomegalovirus recognizes an epitope encoded by exon 2 of the major immediate early gene.

Monoclonal antibody (MAb) E-13 to human cytomegalovirus is used widely for diagnostic and fundamental studies, and has been shown to be directed against an immediate early (IE) protein(s). To determine which viral antigen is detected by MAb E-13, four subfragments from the open reading frame encoded by exons 2, 3 or 4 of IE-1 were cloned in the bacterial expression vector pROS. The resulting fusion proteins contained amino acids 77 to 491 encoded by mainly exon 4, amino acids 25 to 78 encoded by exon 3, amino acids 1 to 85 encoded by exons 2 and 3, and amino acids 1 to 24 encoded by exon 2. The reactivity of MAb E-13 with the fusion proteins was assayed by Western blotting. MAb E-13 was shown to react exclusively with proteins encoded by exon 2 and therefore recognizes IE proteins which contain the N-terminal amino acid sequence encoded by exon 2, namely the major 72K IE protein, the 82K to 86K IE-2 protein and the 52K to 55K IE-2 protein. MAb E-13 can be used to detect both IE-1- and IE-2-encoded proteins, which share the polypeptide encoded by exon 2.

Antibodies, Monoclonal↗
PubMed1992

The lower matrix protein pp65 is the principal viral antigen present in peripheral blood leukocytes during an active cytomegalovirus infection.

During an active infection with human cytomegalovirus (HCMV), viral antigen is consistently present in peripheral blood leukocytes. Two monoclonal antibodies (MAbs), CMV-C10 and CMV-C11, are commonly used in the HCMV antigenaemia assay to detect these cells in the peripheral blood of patients suspected of having an active HCMV infection. We demonstrate that the viral antigen detected by these MAbs is the viral structural protein pp65 and not an immediate early antigen as previously reported. Furthermore, significantly fewer leukocytes were found to be positive with MAbs specific for immediate early antigens.

Antibodies, Monoclonal↗
PubMed1992

Detection of cytomegalovirus antibodies by an enzyme-linked immunosorbent assay using recombinant polypeptides of the large phosphorylated tegument protein pp150.

Parts of the large phosphorylated tegument protein, pp150, of human cytomegalovirus (HCMV) were expressed in bacteria. The resulting fusion proteins were tested in a Western blot (immunoblot) assay for reactivity with a monoclonal antibody against pp150, with a polyspecific rabbit antiserum, and with human reconvalescent-phase sera. Those fusion proteins that performed well in the Western blot assay were used as antigens in enzyme-linked immunosorbent assays (ELISAs) for the detection of antibodies against HCMV. Five different recombinant beta-galactosidase fusion proteins were evaluated by ELISA using 62 seropositive and 38 seronegative human serum samples. Of all the proteins tested, one peptide representing 162 amino acids of pp150 was superior to the others with regard to sensitivity and specificity. All sera known to be positive for antibodies against HCMV were identified by combining the results of the ELISAs with the different pp150 fusion proteins. Therefore, it appears that peptides from a single protein of HCMV might be sufficient to identify HCMV-seropositive individuals by recombinant ELISA.

Animals↗
PubMed1992

Recombinant antigens in viral diagnosis.

DNA-fragments coding for a variety of different viral antigens have been cloned and expressed in E. coli. Selected purified recombinant antigens were used for detection of specific antibodies by the means of ELISA technique. This approach has been used for the development of four different ELISA's for the detection of HIV- and EBV-specific antibodies.

Antibodies, Viral↗
PubMed1992

Recombinant antigens in viral diagnosis.

DNA fragments coding for a variety of different viral antigens have been cloned and expressed in Escherichia coli. Selected purified recombinant antigens were used for detection of specific antibodies by means of the ELISA technique. This approach has been used for the development of four different ELISAs for the detection of HIV- and EBV-specific antibodies.

Antibodies, Viral↗
PubMed1991

Alpha-lipoic acid is an effective inhibitor of human immuno-deficiency virus (HIV-1) replication.

Alpha-lipoic acid, a naturally occurring disulfide-compound that acts as a cellular coenzyme, inhibits replication of HIV-1 in cultured lymphoid T-cells. Alpha-lipoic acid was added 16 hours after infection of the T-cell lines Jurkat, SupT1 and Molt-4 with HTLV IIIB and HIV-1 Wal (a wild type HIV-1 isolate). We observed a dose dependent inhibition of HIV-1-replication in CPE (Cytopathic effect) formation, reverse transcriptase activity and plaque formation on CD4-transformed HeLa-cells. An over 90% reduction of reverse transcriptase activity could be achieved with 70 micrograms alpha-lipoic acid/ml, a complete reduction of plaque-forming units at concentrations of greater than or equal to 35 micrograms alpha-lipoic acid/ml. An augmentation of the antiviral activity was seen by combination of zidovudine and low dose of alpha-lipoic acid (7 micrograms/ml). Trypan blue staining revealed no toxic effects of alpha-lipoic acids on peripheral blood mono-nuclear cells and T-cell lines even in concentrations of greater than or equal to 70 micrograms/ml. Therefore, we propose the inclusion of alpha-lipoic acid into chemotherapy trials in combination with zidovudine.

Cells, Cultured↗