Correlation of HBV DNA and monoclonal reactivity to HBsAg in serum of patients with HBV infection

Mathematical model of antiviral immune response. I. Data analysis, generalized picture construction and parameters evaluation for hepatitis B

The present approach to the mathematical modelling of infectious diseases is based upon the idea that specific immune mechanisms play a leading role in development, course, and outcome of infectious disease. The model describing the reaction of the immune system to infectious agent invasion is constructed on the bases of Burnet's clonal selection theory and the co-recognition principle. The mathematical model of antiviral immune response is formulated by a system of ten non-linear delay-differential equations. The delayed argument terms in the right-hand part are used for the description of lymphocyte division, multiplication and differentiation processes into effector cells. The analysis of clinical and experimental data allows one to construct the generalized picture of the acute form of viral hepatitis B. The concept of the generalized picture includes a quantitative description of dynamics of the principal immunological, virological and clinical characteristics of the disease. Data of immunological experiments in vitro and experiments on animals are used to obtain estimates of permissible values of model parameters. This analysis forms the bases for the solution of the parameter identification problem for the mathematical model of antiviral immune response which will be the topic of the following paper (Marchuk et al., 1991, J. theor. Biol. 15).

In vitro inhibition of hemopoietic cell line growth by hepatitis B virus

The effects of hepatitis B virus (HBV) on established human cell lines of various tissue origins were evaluated by clonal or colorimetric assays in methylcellulose culture. HBV exposure inhibited the growth of six hemopoietic cell lines, while similar incubation did not affect the growth of seven nonhemopoietic carcinoma cell lines of breast, colon, liver, and stomach origin. The inhibition of hemopoietic cell line colony formation was dependent on the presence of intact viral (Dane) particles and the ratio of exposure of virions to cells and was reversible with antibodies to pre-S1, pre-S2, and S envelope protein epitopes. Purified HBV DNA, surface antigen pre-S antigens, and core antigen did not inhibit cell line growth. These results further demonstrate the tropism of HBV for cells of hemopoietic origin, confirming our previous findings on the effects of HBV on the growth of normal bone marrow progenitor cells in vitro. Established human tissue culture cell lines may be used to study the interactions of hemopoietic cells with HBV.

Preliminary evidence that azidothymidine does not affect hepatitis B virus replication in acquired immunodeficiency syndrome (AIDS) patients

The effect of azidothymidine (AZT) on hepatitis B virus (HBV) replication was determined in three patients with the acquired immunodeficiency syndrome (AIDS). Serum viral DNA was present, and its concentration either remained the same or increased in two patients. Since AIDS patients may be infected with a variety of viral agents in addition to the human immunodeficiency virus (HIV), the effects of the antiviral agents and biological modifiers on other common viral infections should also be determined in developing new approaches to HIV infection. Our results give preliminary evidence that AZT does not affect HBV viral replication in vivo.

Direct method for detecting small quantities of hepatitis B virus DNA in serum and plasma using the polymerase chain reaction

Serum components inhibit DNA polymerase, thereby obviating direct detection of serum viral DNA sequences by the polymerase chain reaction (PCR). This has necessitated extraction of nucleic acid from sera before performing PCR and has resulted in loss of sensitivity. By adsorbing virus to a solid surface (microcentrifuge tubes or antibody coated microparticles) followed by proteinase K digestion, as little as three viruses per 200 microliters serum may be directly detected by PCR without nucleic acid extraction. The sensitivity is dependent on the surface area of the adsorptive surface and is increased by having antibodies on the adsorptive surface. The nucleic acid sequence of the amplified DNA fragments may be directly determined by the dideoxy method. Of 24 plasma samples from HBsAg+ volunteer blood donors, HBV DNA was detected in 7 by dot blot assay, 7 by liquid hybridization, and 9 by PCR. PCR detected DNA in every sample that was positive by another assay. Analysis of serial samples of two patients with acute self-limited hepatitis B found detectable HBsAg and pre-S2 antigenemia before HBV DNA by the PCR method. These results suggest that surface antigenemia may precede viremia during acute hepatitis.

Rapid identification of low level hepatitis B-related viral genome in serum

A sensitive and specific method has been developed to detect hepatitis B virus (HBV) in serum. The method involves two steps: the capture of viral genome from serum using a high affinity IgM monoclonal antibody directed against a common a domain epitope found on the envelope, and the amplification of viral DNA by the polymerase chain reaction (PCR). The amplification is initiated using "generic" primers derived from the core and pre-core sequences which are highly conserved amongst the hepadnaviruses. This rapid technique detects less than 10 infectious virions and may be useful in the study of individuals with acute and chronic liver disease of unknown etiology.

Comparison of serum hepatitis B virus replication markers in patients with chronic hepatitis B: studies on HBeAg/anti-HBe system, viral DNA polymerase and HBV-DNA

The detection of HBV-DNA in serum by molecular hybridization is the most sensitive and specific marker or replication and infectivity of hepatitis B virus and currently is proposed as a routine diagnostic technique in the follow-up of HBV-related diseases. Comparing different techniques already described, we found that direct spotting of serum samples on nitrocellulose membranes under vacuum filtration, followed by denaturing and neutralizing washes is more practical, simple, sensible and reproducible. DNA polymerase assay using phosphonoformic acid as specific viral inhibitor has shown 86.8% of concordance with HBV-DNA detection, and so, it is an useful alternative in the follow-up of hepatitis B chronic patients. We found 19.2% HBeAg positive samples with no other markers of viral replication and no anti-HBe positive sample had detectable HBV-DNA. Discordance between the 2 systems have been extensively described, and we confirm this for the first time in our country. Molecular biological techniques are essential to determine the replication status of chronic hepatitis B patients.

Isolated presence of antibody to hepatitis B core antigen in dialysis patients: occurrence of subclinical hepatitis?

Hepatitis B core antibody (anti-HBc) has recently been recognized as a paradoxical (surrogate) marker for non-A, non-B hepatitis agents in donated blood. We studied prospectively the hepatitis B virus antigen and antibody status and liver functions in 63 uremic patients admitted consecutively to our dialysis program. Nineteen percent of uremic patients, negative for hepatitis B surface antigen (HBsAg), hepatitis B virus surface antibody (anti-HBs), hepatitis B virus DNA, and antibody to delta agents, had anti-HBc in their sera at the time of admission to maintenance dialysis. This prevalence was significantly higher than that of the medical personnel working in the dialysis unit (P = 0.043) and healthy controls (P = 0.027). The prevalence of persistent presence of isolated anti-HBc increased to 31% in these uremic patients on long-term maintenance dialysis. Four patients had developed anti-HBc alone during their course of maintenance dialysis, and the appearance of anti-HBc was preceded by blood transfusion within 4 to 8 weeks. Transient or recurrent hepatic dysfunction occurred in three of these four patients. Patients with isolated anti-HBc were characterized by a higher incidence of repeated liver dysfunction (P less than 0.005), elevated alanine transaminase levels (P less than 0.005), and a higher transfusion requirement (P less than 0.01). Our data strongly suggest that these patients with isolated anti-HBc may have acquired either hepatitis B virus infection or non-A, non-B hepatitis through repeated blood transfusions despite careful screening of the donated blood to exclude transmission of hepatitis B virus.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro hepatitis B virus suppression of erythropoiesis is dependent on the multiplicity of infection and is reversible with anti-HBs antibodies

Exposure of human bone marrow mononuclear cells to hepatitis B virus results in the suppression of the in vitro growth of several hematopoietic progenitor cells. We studied the degree of inhibition of erythroid progenitor cells that results as a function of the time of exposure of mononuclear cells to hepatitis B virus and the ratio of virus to mononuclear cells, the multiplicity of infection. With an overnight incubation of mononuclear cells with hepatitis B virus-containing sera, a multiplicity of infection of greater than one virus per mononuclear cell is required to observe significant inhibition of erythroid colony formation. This multiplicity of infection effect is also observed with purified Dane particles. Exposure of mononuclear cells to an increasing number of Dane particles results in a dose-dependent suppression of erythroid colony formation with significant inhibition observed with a multiplicity of infection of virus to mononuclear cells as low as 5:1. Murine monoclonal antibodies to HBsAg completely neutralize the hepatitis B virus-mediated inhibition of CFU-E while control antibodies do not. Purified HBsAg has no effect on colony formation. In conclusion, the hepatitis B virus-mediated inhibition of erythrogenesis in vitro provides a basis for understanding the bone marrow depression observed during hepatitis B virus infections and may provide an in vitro model for examining hepatitis B virus infection.