Radioimmunoprecipitation in the diagnosis of chronic active Epstein-Barr virus infection.

Chronic active Epstein-Barr virus (EBV) infection occurs sporadically in a small fraction of individuals infected with EBV. A clear definition of the disease and an unambiguous diagnostic test are still lacking. In an attempt to identify a serologic marker to facilitate the diagnosis, immunoblot and radioimmunoprecipitation assay (RIPA) were compared with standard immunofluorescence on 39 available sera. Results by RIPA revealed that antibodies to a 120 kDa viral protein correlated with the presence of chronic active EBV infection; these antibodies were not detected in sera from other EBV-seropositive individuals, with the exception of one of two patients with ataxia telangiectasia. Also, RIPA was the most sensitive technique for detecting EBV antibodies in sera weakly or doubtfully positive for antibody to EB viral capsid antigen by indirect immunofluorescence. All these sera had antibodies to the 150 kDa protein, also known as p160, the major viral capsid antigen.

Deficient expression of enhanced reactivation of parvovirus H-1 in ataxia telangiectasia cells irradiated with X-rays or u.v. light.

Cells of patients with ataxia telangiectasia (AT), an inherited disease characterized by a high propensity to cancer, are hypersensitive to ionizing radiation. We investigated whether the hyper-radiosensitivity of AT cells correlated with a defect in their constitutive and/or conditional ability to rescue a damaged exogenous virus. For that purpose, parvovirus H-1, a single-stranded DNA virus whose intranuclear replication mostly relies on host cell functions, was used as a probe. The survival of u.v.- or gamma-irradiated H-1 was measured in X-, u.v.- or mock-irradiated human cells of normal (NB-E) or AT (AT5BIVA) origin. gamma-Irradiated H-1 survived to similar extents in untreated normal and AT cell lines. Both X- and u.v.-irradiation induced normal cells to achieve an enhanced reactivation (ER) of gamma- or u.v.-damaged H-1. In contrast, neither dose-effect curves nor time course revealed significant levels of ER expression after X- or u.v.-irradiation in AT5BIVA cells. Our results suggest that the impairment of ER of damaged parvoviruses may constitute a marker of the AT cell phenotype and be related to the radiosensitivity of AT cells.

[Cells of patients with ataxia telangiectasia show a normal capacity of radio-induced reactivation of damaged HSV-1 virus]. / Les cellules de patients atteints d'ataxia telangiectasia manifestent une capacité normale de réactivation radioinduite du virus HSV-I endommagé.

Herpes Simplex Virus (HSV-1) was used to probe the expression of enhanced reactivation (ER) in cells from patients with ataxia telangiectasia (AT). The survival of UV-irradiated HSV-1 was increased as a result of UV- or X-preirradiation of both AT and normal cells. This result contrasts with our previous observation showing that contrary to normal cells AT cells are deficient for ER of a single-stranded DNA parvovirus. A difference between the molecular processes underlying ER of single- and double-stranded DNA viruses might explain these results.

Transformation and repair replication in lymphocytes from ataxia telangiectasia.

Peripheral blood leukocytes (PBL) isolated from five patients with ataxia telangiectasia (AT) proved more difficult to transform following addition of exogenous Epstein-Barr virus than PBL isolated from AT heterozygotes or normal adults. PBL isolated from one AT patient transformed within the range expected for normal PBL. Once established in culture, the resulting lymphoblastoid cell lines (LCLs) were immortal and, though they grew slower than normal control LCLs, provided useful material for studying cellular phenotypes associated with AT lymphoid cell lines. All the resulting LCLs established from ataxia were more sensitive to X-irradiation than were LCLs established from controls as measured by colony formation in microtiter plates. Furthermore, X-ray-induced inhibition of semiconservative DNA synthesis in ataxia LCLs was less than that seen in normal LCLs. These results are in agreement with those obtained using cultured AT fibroblasts, indicating that in vitro transformation by exogenously added Epstein-Barr virus does not alter the phenotype of the ataxia cell as measured by these two parameters. However, no deficiency in X-ray-induced excision repair of DNA was demonstrable in LCLs established from four AT patients. Nor was there a deficiency in AT LCL host cell reactivation of herpes simplex virus X-irradiated under anoxic conditions. Taken together, these data point toward a defect in ataxia lymphoblasts other than repair enzyme(s) per se, one possibly associated with chromosomal structure, function, or modification.

Retrovirus-like particles in EBV-negative Burkitt's lymphoma cell line but not in EBV-DNA-positive lines from patients with ataxia telangiectasia and Down's syndrome.

Retrovirus-like particles can be recovered by arginine deprivation from the BJAB-1 Epstein-Barr virus (EBV) negative cell line derived from an African patient with typical Burkitt's lymphoma. These particles resemble retroviruses in their morphology and in their physicochemical properties. Particles with a similar morphology were obtained from derivative cell lines established by infecting BJAB-1 cells with EBV. On the other hand, retrovirus-like particles could not be induced in EBV-DNA-positive lymphoblastoid cell lines derived from non-leukaemic patients with ataxia telangiectasia and Down's syndrome and from a patient with infectious mononucleosis.