Inactivation of E2a in recombinant adenoviruses improves the prospect for gene therapy in cystic fibrosis.

Although first generation recombinant adenoviruses, deleted of sequences spanning E1a and E1b, have been useful for in vivo applications of gene therapy, expression of the recombinant gene has been transient and often associated with the development of inflammation. We show that with first generation adenovirus-mediated gene transfer to the mouse lung, viral proteins are expressed leading to destructive cellular immune responses and repopulation of the lung with nontransgene containing cells. Second generation E1 deleted viruses further crippled by a temperature sensitive mutation in the E2a gene were associated with substantially longer recombinant gene expression and less inflammation. Stable expression of human CF transmembrane conductance regulator has been achieved in lungs of CF mice instilled with a second generation virus.

Human cytomegalovirus induces stage-specific embryonic antigen 1 in differentiating human teratocarcinoma cells and fibroblasts.

Cell surface expression of stage specific embryonic antigen 1 (SSEA-1), or Lex (III3 FucnLC4), was induced in differentiated human teratocarcinoma cells and in human diploid fibroblasts 3-6 d after infection with human cytomegalovirus (HCMV). In parallel, fucosylated lactoseries glycolipids bearing the SSEA-1/Lex epitope were readily detected in the infected cells but not in the uninfected cells. HCMV infection also results in altered expression of several glycosyltransferases. SSEA-1/Lex induction is probably a consequence of both increased expression of beta 1----3N-acetylglucosaminyltransferase, which catalyzes the rate-limiting step in lactoseries core chain synthesis, and subtle alterations in the relative competition for common precursor structures at key points in the biosynthetic pathway. Since SSEA-1 has been suggested to play a role in some morphogenetic cell-cell interactions during embryonic development, the induction of this antigen at inappropriate times might provide one mechanism whereby intrauterine infection with HCMV can damage the developing fetal nervous system.

Cytomegalovirus replicates in differentiated but not in undifferentiated human embryonal carcinoma cells.

To study the mode of action of human cytomegalovirus, an important teratogenic agent in human populations, the susceptibility of a pluripotent human embryonal carcinoma cell line to the virus was investigated. Viral antigens were not expressed nor was infectious virus produced by human embryonal carcinoma cells after infection, although the virus was able to penetrate these cells. In contrast, retinoic acid-induced differentiated derivatives of embryonal carcinoma cells were permissive for antigen expression and infectious virus production. Replication of human cytomegalovirus in human teratocarcinoma cells may therefore depend on cellular functions associated with differentiation.

Independent and joint effects of antibodies to human heat-shock protein 60 and Chlamydia pneumoniae infection in the development of coronary atherosclerosis.

BACKGROUND: Studies have suggested that the prevalence of antibodies against heat-shock proteins (HSPs), Chlamydia pneumoniae (CPN), and cytomegalovirus (CMV) is associated with coronary artery disease (CAD), but the independent or joint effects of human (h) HSP60 antibodies and these pathogens in patients have not been fully elucidated. METHODS AND RESULTS: A total of 405 subjects (276 patients with CAD and 129 control individuals) were tested for serum antibodies to hHSP60, CPN, and CMV immediate-early-1 (IE1) antigens. Patients were also assessed for serum cholesterol, triglyceride levels, and smoking habit. Significantly elevated levels of antibodies to hHSP60 and CPN but not to CMV-IE1 antigens were documented in CAD patients. Multiple logistic regression analysis and subanalyses of selected subjects showed that these associations were independent of age, sex, smoking, and serum lipid levels. Antibodies to hHSP60 and CPN did not correlate quantitatively; however, the relative risk of disease development was substantially increased in subjects with high antibody levels to both hHSP60 and CPN:, reaching an odds ratio of 82.0 (95% CI 10.6 to 625.0). CONCLUSIONS: High levels of antibodies to hHSP60 and CPN: are independent risk factors for coronary atherosclerosis, but their simultaneous presence substantially increases the risk for disease development.

Chlamydia pneumoniae in atherosclerotic middle cerebral artery.

BACKGROUND AND PURPOSE: Atherosclerotic middle cerebral arteries are frequent sites of thrombosis, leading to stroke. Previous studies have suggested a role for Chlamydia pneumoniae in the pathogenesis of atherosclerosis. However, the presence of this pathogen in atherosclerotic middle cerebral arteries has heretofore not been documented. In the present study, we analyzed atheromatous plaques from middle cerebral arteries for the presence of C pneumoniae. METHODS: Atherosclerotic middle cerebral arteries from 15 cadavers who died of natural causes and corresponding nonatherosclerotic arteries from 4 otherwise healthy trauma victims were examined. Assays for C pneumoniae DNA were carried out by nested polymerase chain reaction (nPCR) specific for the C pneumoniae ompA gene. The presence of the bacterium was assessed by transmission electron microscopy. RESULTS: Five of the 15 atherosclerotic arterial samples and none of the control tissues were positive for C pneumoniae by nPCR. Particles similar in morphology and size to C pneumoniae elementary bodies were detected by transmission electron microscopy in 4 of the 5 nPCR-positive atherosclerotic samples. CONCLUSIONS: The demonstration of C pneumoniae in atherosclerotic middle cerebral arteries is consistent with the hypothesis that this bacterium is involved in acute and chronic cerebrovascular diseases.

Protracted mononucleosis-like illness associated with acquired cytomegalovirus infection in a previously healthy child: transient cellular immune defects and chronic hepatopathy.

Ordinarily, severe disease due to acquired cytomegalovirus (CMV) infection does not occur in immunocompetent children. We describe a previously healthy boy who acquired primary CMV infection at approximately 2 years of age and experienced a 2-year-long debilitating multisystem illness from which he ultimately recovered. Clinical features of this illness included fatigue, poor weight gain, pallor, unexplained fever, musculoskeletal complaints, drenching night sweats, lymphadenopathy, and massive hepatosplenomegaly. Laboratory abnormalities included elevated erythrocyte sedimentation rate, lymphocytosis, and elevated immune complex levels. Cellular immune function was impaired during the illness but was demonstrably normal during convalescence, and there was no other evidence for a known immunodeficiency state. Immunoblot analysis showed enhanced antibody response to a 66-kd infected cell protein after symptomatic recovery. Despite consistently normal indices of hepatic function, liver enlargement persisted after other symptoms had resolved. Liver biopsy demonstrated a mononuclear cell portal tract infiltrate with fibrosis, but CMV could not be demonstrated directly in this tissue. Primary CMV infection has not been reported previously to cause the persistent symptoms seen in this child.

Human immunodeficiency virus type 1 tat gene enhances human cytomegalovirus gene expression and viral replication.

Clonal lines of human rhabdomyosarcoma (RD) cells, constitutively expressing human immunodeficiency virus type 1 (HIV-1) tat gene (RD tat cell lines) showed enhanced expression of human cytomegalovirus (HCMV) immediate-early (IE) and late (L) proteins upon HCMV infection, as compared with control RD cells. One of the RD tat cell lines produced infectious HCMV. The RD-tat cell lines, following transfection with recombinant plasmids containing the full length of the HCMV-IE enhancer/promoter linked to the bacterial chloramphenicol acetyltransferase (CAT) gene, exhibited an increased CAT expression by the tat product. A chronically HIV-1-infected human T-lymphoid cell line, SupT1, superinfected with HCMV, expressed HCMV-IE proteins while the parental SupT1 cells infected with HCMV were negative. Parental SupT1 cells coinfected with HIV-1 and HCMV also expressed HCMV-IE proteins, indicating that HIV-1-encoded proteins exert a positive regulatory effect on HCMV expression.

Development of a cytomegalovirus vaccine: lessons from recent clinical trials.

Cytomegalovirus-caused diseases are preventable. We believe that both neutralising antibodies and cell-mediated immunity are necessary for prevention. Of the CMV proteins, gB and pp65 are the minimum requirements in a vaccine to induced neutralising antibodies and cytotoxic T-lymphocyte (CTL) responses. Immunisation with additional proteins, e.g., gH, gN for neutralising antibodies and IE1exon 4 and pp150 for CTL responses, would strengthen protective immune responses. Approaches to development of a safe and effective cytomegalovirus (CMV) vaccine for the prevention of CMV diseases include: a) a live attenuated vaccine (Towne strain); b) recombinant constructs of the attenuated Towne and the virulent Toledo CMV strains; c) subunit glycoprotein B (gB) adjuvanted with MF59 to induce neutralising antibodies; d) phosphoprotein 65 (pp65) peptide-based vaccines to induce (CTL) for use in therapeutic vaccination; e) canarypox-CMV recombinants, e.g., ALVAC-CMV(gB) and ALVAC-CMV (pp65) to induce neutralising antibodies and CTL responses, respectively; f) DNA plasmids containing the genes for gB and pp65; g) dense bodies containing the key antigens. The attenuated Towne strain, gB/MF59, ALVAC-CMV(gB) and ALVAC-CMV(pp65) approaches have already been tested in clinical trials. The Towne vaccine induced neutralising antibodies and cell-mediated immunity (including CTLs) mitigated CMV disease in seronegative renal transplant recipients and protected against a low-dose virulent CMV challenge in normal volunteers but did not prevent infection in mothers of children excreting CMV. Immunisation with gB/MF59 resulted in high levels of neutralising antibodies in seronegative subjects. ALVAC-CMV(gB) did not induce neutralising antibodies but primed the immune system to a Towne strain challenge, while ALVAC-CMV(pp65) induced long-lasting CTL responses in all originally seronegative volunteers, with CTL precursor frequency similar to naturally seropositive individuals. These results suggest that CMV diseases can be prevented or attenuated and that a vaccine combining ALVAC-CMV(pp65) with gB/MF59 may induce sufficient CTLs and neutralising antibodies to protect against CMV diseases. Meanwhile, other approaches such as DNA peptide and dense body vaccines, should enter Phase I trials. All candidate vaccines will have to demonstrate that immunogenicity provides protection. Combined vaccines containing canarypox (ALVAC) vectors to express CMV-pp65 to induce CTLs and of subunit gB, given together with an appropriate adjuvant to induce neutralising antibodies, should be tested in a target population for the prevention of CMV infection and disease.

A rapid microneutralization assay for cytomegalovirus.

A rapid, simple and reproducible microneutralization test for human cytomegalovirus is described. The results can be read in 1-2 days and the neutralization titer detected in human and guinea pig sera and in monoclonal antibody-containing supernatants is consistent with that derived by the plaque-reduction neutralization test.

Minitransfection: a simple, fast technique for transfections.

A fast, simple and inexpensive minitransfection technique, using either a lipofection or a calcium phosphate coprecipitation method to introduce foreign DNA into living cells is presented. This technique is based on the use of 24-well or 96-well tissue culture plates and can be used for both transient and stable transfections. Because it is a microtechnique, only small amounts of DNA, cells and transfection reagents are necessary, and it is easy to handle multiple DNA transfections or cotransfections in different cell lines and in duplicates or triplicates. The technique can be used to study viral gene expression, virus replication and chloramphenicol acetyltransferase (CAT) assay in different cell lines, for example, in the large scale screening and testing of antiviral agents.

Application of near infrared spectroscopy to the determination of haemoglobin.

Seventy-two whole blood samples were investigated to determine the relationship between their spectral data measured in the near infrared (NIR) wavelength region and haemoglobin content based on laboratory data determined by a routine standard method as reference. Blood samples were obtained from the 1st Department of Medicine, Imre Haynal University of Health Sciences. Donors were selected randomly without respect to age, sex, state of health or medical treatment, from apparently healthy volunteers as well as from ambulatory and hospitalized patients. NIR spectra were measured with a SPECTRALYZER 1025 (PMC) computerized spectrophotometer in the 1000-2500 nm wavelength region. The relationship between laboratory data and values of the second derivative (i.e. second order finite difference) of the log(1/TF) spectra measured at different wavelengths was determined by multiple linear regression (MLR) using three- and four-term linear summation equations. The cross-validated standard error of performance (SEP) for haemoglobin was 1.348 g dL-1 with a three term model and 1.251 g dL-1 with a four term model over the range from 5.9 to 20 g dL-1. This preliminary study indicates that NIR measurements can be directly related to haemoglobin content and can be used to determine haemoglobin content in human whole blood.

Latent infection of mouse cells with human cytomegalovirus.

Infection of secondary mouse fibroblast cultures with human cytomegalovirus (HCMV) led to the production of viral antigens in the absence of detectable virus replication. Antigen production was not dependent on viral DNA synthesis since it was not inhibited by cytosine arabinoside. Beginning at 15 days post-infection, viral-specific antigens were no longer observable in infected cultures, but could be induced by iododeoxyuridine (IUDR) treatment. Such cultures carry HCMV genetic information in a latent, unexpressed, state. Fusion of latently-infected mouse cells with human fibroblasts also induced viral-specific antigens, but no detectable virus replication, in the resulting heterokaryons. However, upon IUDR treatment of heterokaryons, or of the mouse cells prior to fusion, antigens characteristic of the late stages of virus replication appeared, and infectious CMV could be detected. Thus, it appears that the non-permissive (mouse) cell genome is dominant, and continues to regulate viral gene expression in heterokaryons formed with permissive (human) cells.

Monoclonal antibodies directed to two groups of viral proteins neutralize human cytomegalovirus in vitro.

Monoclonal antibodies (MAbs) that neutralized human cytomegalovirus (HCMV) were produced by ten hybrid cells lines, generated from BALB/c mice immunized with HCMV-infected human fibroblasts. By immunoblot technique six antibodies detected a set of HCMV glycosylated polypeptides which, when separated under reducing conditions, migrated with apparent molecular weights (m.wt.) of 47.5K, 51K, 54K, 58K, and 60-69K. One other antibody reacted only with the 47.5 and 51K polypeptides and the 60-69K broad band. Under nonreducing conditions, these antibodies showed no reactivity with any polypeptide. The three remaining MAbs reacted with two high-m.wt. polypeptides of approximately 200K and greater than 200K when separated under nonreducing conditions. One of these antibodies showed no clear reactivity with the polypeptides, one detected a 58K and 92-94K species and one detected a 58K and 130K species, when separated under reducing conditions.

Cloned antigens and antiidiotypes.

Both monoclonal and polyclonal antiidiotypic antibodies mimicking the human colorectal carcinoma (CRC) associated antigen CO17-1A/GA733 have induced antigen-specific humoral and cellular immunity in CRC patients. The immune responses may underlie the clinical responses observed in some of the treated patients. Recently, the CO17-1A/GA733 antigen has been molecularly cloned and expressed in baculo-, adeno-, and vaccinia viruses. In preclinical studies, these recombinant antigen preparations elicited specific humoral immunity (cytotoxic antibodies) and cellular immunity (DTH-reactive and proliferative T cells). Antibody titers elicited in animals by recombinant antigen were significantly higher than those elicited by antiidiotypes. The recombinant antigen has a potential as a vaccine for CRC patients.

Inflammatory- and immune responses in relation to bacterial replication in mice following re-infections with Chlamydophila pneumoniae.

OBJECTIVE: Investigation of chronic infections with Chlamydophila pneumoniae. METHODS: BALB/c mice were repeatedly infected with C. pneumoniae and tested during a 1-year period. Production of histamine, IFN-gamma, IL-6 and antibodies was monitored by ELISA. Live bacteria were cultured and DNA was detected by PCR. Cellular immunity was tested by ELISPOT. RESULTS: After re-infections, culture positivity and persistence of DNA in lungs and blood were shorter. Detection of DNA at late time points indicated persistent infection in a few mice. Histamine was produced after primary and re-infections, and the level correlated with the number of viable bacteria in lung. IFN-gamma, IL-6 levels, IgG2/IgG1 ratio, IgA titres, and level of chlamydial heat-shock protein antibodies were higher after re-infections. IgM antibodies were demonstrated even after re-infections. High number of IFN-gamma-producing splenocytes was observed after the third inoculation. CONCLUSION: These results promote an understanding of the patho- and immune mechanisms after C. pneumoniae re-infections.

Chronic infections and histamine, CRP and IL-6 levels after percutaneous transluminal coronary angioplasty.

OBJECTIVE AND DESIGN: Our hypothesis was that percutaneous transluminal coronary angioplasty (PTCA) reactivates certain pathogens that contribute to inflammatory processes after the intervention. SUBJECTS: We determined the levels of antibodies to human Hsp60 and levels of histamine, CRP and IL-6 in sera from 28 patients of unstable angina prior to and on days 4 and 14 after PTCA. We compared the presence of Chlamydophila pneumoniae (Cpn) and human cytomegalovirus (HCMV) DNA in peripheral blood, and levels of antibodies to Cpn, HCMV, herpes simplex virus, Epstein-Barr virus and mycobacterial Hsp65 in the serum. RESULTS: Higher prevalence of Cpn and HCMV DNA was demonstrated after PTCA than before, but titers of antibodies to the pathogens did not increase. Levels of histamine, CRP and IL-6 were enhanced after PTCA. There was no association between the levels of histamine, CRP and IL-6 and the rate of pathogen DNA, or antibody titers to the pathogens, except an association between Cpn IgA and histamine levels before PTCA. CONCLUSIONS: Reactivation of Cpn and HCMV and inflammatory change characterized by increased levels of histamine, CRP and IL-6 following PTCA are suggested. An association might exist between Cpn IgA antibody and histamine levels in patients of unstable angina.

A soluble factor(s) released by MRC-5 cells early and late after human cytomegalovirus infection induces maturation of monocyte-derived dendritic cells.

A human cytomegalovirus (HCMV) strain passaged 10 times on MRC-5 human fibroblast cells failed to express immediate early (IE) antigens in immature dendritic cells (iDCs) after infection. However, both the early and the late HCMV conditioning medium, harvested from MRC-5 cells at 24 h or 7-9 days after infection, respectively, induced a higher ratio of DCs expressing maturation markers (CD40, CD83, CD86 and HLA-DR) on the surface of the cells. HCMV conditioning medium, ultracentrifuged to remove virus particles, exhibited a similarly enhanced expression of DC maturation markers. DCs treated with HCMV conditioning medium harvested late after infection increased the percentages of autologous CD4+ and CD8+ cells of seropositive donors to produce IFN-gamma and stimulated HCMV-specific lymphoproliferative responses. The early HCMC conditioning medium was also able to induce the functional maturation of DCs, as demonstrated by supplementing this medium with a Chlamydia pneumoniae antigen.