Detection of Epstein-Barr virus transcripts in chemically or immunologically-activated cells and in a null cell-line (HLN-STL-C) by in situ hybridization with alkaline phosphatase-linked oligonucleotide probes.

We report a simple procedure for the detection of Epstein-Barr virus (EBV) by in situ DNA-RNA hybridization with an alkaline phosphatase-linked oligonucleotide probe. EBV-producing cell lines P3HR-1 and Akata were treated with phorbol ester and n-butyrate, and anti-human IgG, respectively. This treatment resulted in highly increased populations of cells with EBV transcripts of the latent membrane protein 1 (LMP1) and envelop glycoprotein gp350/220, but not of EBV-encoded small nuclear RNAs (EBERs). Synthesis of the LMP1 protein, which was encoded by the induced mRNA, was mostly dependent on viral DNA synthesis, as shown by double or single labeling for in situ DNA-DNA hybridization with the oligo-nucleotide probe, and immunoperoxidase staining with a monoclonal antibody against LMP1. In situ hybridization of the null cell line HLN-STL-C established from an adult T-cell leukemia patient showed that 100% of the cells contained both EBERs and LMP1 mRNA and about 0.1% of the cells contained gp350/220 mRNA, indicating that a few of the null cells which carried the EBV genome spontaneously entered the late EBV replication cycle.

A novel EBV-related nucleo-cytoplasmic antigen in a null cell-line (HLN-STL-C) reactive to antibodies in the sera from patients with Sjögren's syndrome.

We have established a non-T- and non-B-cell line, HLN-STL-C(STL-C), which harbors the EBV genome, from the lymph node cells of a Japanese ATL patient. This cell line expresses a unique Epstein-Barr virus (EBV)-related nucleo-cytoplasmic (N-C) antigen which is detected by indirect immunofluorescence (IF) with the sera from patients with nasopharyngeal cancer (NPC), infectious mononucleosis (IM) or adult T-cell leukemia (ATL). One of the molecular components of this antigen is proved to be STL-C specific 125 kD molecule by immunoblot analysis (IB). To study the involvement of EBV in Sjögren's syndrome (SS), we examined the reactivity of the N-C antigen with the sera of SS patients by IF and IB. Among 24 cases examined, the sera of 21 cases (87.5%) positively stained the N-C antigen by IF. The staining patterns were divided into two types. Type I, (seven cases) showed positive staining for only N-C antigen, and Type II, (14 cases) was positive for N-C antigen associated with diffuse nuclear staining due to antinuclear antibodies in the SS patient's sera. Only one out of 11 non-Sjögren's patients' sera, which were almost all healthy controls, was positive for N-C antigen in this study. By IB, however, only two out of 15 IF-positive SS patients' sera reacted with STL-C specific 125 kD molecule. These results suggested the presence of heterogenous components in the N-C antigen. Our findings may support the hypothetical conception that EBV plays an etiological role in SS.

Human peripheral blood null lymphocytes stimulated by Staphylococcus aureus Cowan I produce atypical acid-labile interferon in vitro.

Peripheral blood mononuclear leucocytes (PBLs) stimulated in vitro by heat-killed formaldehyde-fixed Staphylococcus aureus Cowan I (SACoI) produced acid-labile alpha interferon (IFN-alpha) and, to various extents, also IFN-gamma. The IFN producers resided in nylon wool-nonadherent cells, and monocytes suppressed SACoI-induced IFN responses. Further separation of nonadherent PBLs in accordance with expression of surface antigenic markers was performed with a 'panning' technique. The SACoI induced production of IFN in cells that carried neither surface immunoglobulins nor OKT3-defined antigens. These cells were also characterized as OKM1- and OKT10-negative. In contrast, cells with natural killer (NK) activity against K562 erythroleukaemia cells were located in both OKM1- and OKT10-positive and -negative cells. At centrifugation on Percoll density gradients, cells with NK activity and IFN response against SACoI were recovered from light gradient fractions that contained mainly large granular lymphocytes (LGL). Furthermore, the IFN producers were enriched by removal of sheep erythrocyte-rosetting T cells from the Percoll fractions. These SACoI-induced IFN-producing PBLs are LGL but lack certain antigens that are frequently found on NK cells.

In vitro infection of fractionated chicken lymphocytes by infectious bursal disease virus.

Lymphocytes from bursa of Fabricius and thymus of chickens were purified and separated into the three cell subsets--T, B, and null cells--by the techniques of nylon fiber columns and cytotoxicity tests. The in vitro susceptibility of the fractionated lymphocytes to a virulent strain of infectious bursal disease virus (IBDV) was studied by using immunofluorescence as the infection criterion. B cells were highly susceptible. By contrast, T cells and null cells were insusceptible to infection by IBDV. The relationship between the target cells for virus infection and those B cells that possessed surface immunoglobulin (SIg) was tested. B cells were further divided into SIg(M)- and SIg(G)-bearing cells by immunoadsorbent columns employing anti-immunoglobulin M(IgM) (mu-specific) or anti-IgG (gamma-specific) sera coated with Sephadex. The SIg(M)-bearing cells were highly susceptible. These results suggest strongly that SIg(M)-bearing B cells were the target cells for infection by IBDV.

Epstein-Barr virus (EBV)-lymphoid cell interactions. I. Quantification of EBV particles required for the membrane immunofluorescence assay and the comparative expression of EBV receptors on different human B, T and null cell lines.

We report data on the number of Epstein-Barr virus (EBV) particles required to detect virus binding to target cells (Raji or BJA-B) by means of membrane immunofluorescence (MIF). After determining the optimum conditions for the MIF assay the following aspects of EBV-lymphoid cell interactions were examined: (i) binding of two different strains of EBV to various types of human lymphoid cell lines, (ii) expression of receptors for both EBV and complement on these lines and (iii) induction of EBV-induced nuclear antigen (EBNA) in the different target cells used. The results showed that a minimum of about 2.7 x 10(3) enveloped virus particles/cell were required for an optimum visualization of EBV binding to the target cells tested, and that a lymphoid cell may bear receptors for one prototype strain of EBV but not for the other. A number of cell lines, particularly those of T and null type which express EBV receptors, did not synthesize EBNA, thus indicating that these lines were resistant to EBV infection. Several of these lines, although expressing cell surface EBV receptors, lacked complement receptors.

Interaction of Herpes simplex virus with human cell lines at various stages of lymphoid differentiation.

The growth of herpes simplex virus (HSV) type 1 in human lymphoid cell lines, arrested at various stages of differentiation, was studied. The synthesis of viral DNA and antigens and the production of infectious virus were followed in null, B and T leukemia-lymphoma cell lines. It was found that while "nondifferentiated" null cells and cells differentiating along the B pathway, even at very early stages of differentiation, supported HSV growth, cell lines of T origin at all stages of differentiation were generally nonpermissive. The failure of T cells to support the growth of HSV did not result from inefficient adsorption to the host cells. However, viral DNA synthesis was not detected, and a significant reduction in the ability of synthesize HSV antigens was observed. It is suggested that the block in the growth cycle of the virus occurs at a stage after adsorption of the virion to the cells, but prior to synthesis of its DNA and proteins.