Hepatitis A virus cDNA and its RNA transcripts are infectious in cell culture

A full-length cDNA copy of an attenuated, cell culture-adapted hepatitis A virus (HAV HM-175/7 MK-5) genome was constructed in the PstI site of plasmid vector pBR322. Transfection of monkey kidney cells with this plasmid failed to induce the production of hepatitis A virus (HAV). The HAV cDNA was excised from pBR322 and inserted, without the oligo(dG) X oligo(dC) tails, into an RNA transcription vector to yield plasmid pHAV/7. Transfection of monkey kidney cells with pHAV/7 DNA induced HAV infection. Transfection with RNA transcripts produced in vitro from pHAV/7 yielded about 10-fold more HAV than did transfection with pHAV/7 DNA. Marmosets inoculated with transfection-derived virus developed anti-HAV antibodies and had liver enzyme patterns that closely resembled the liver enzyme patterns seen in animals inoculated with virus from a comparable level of cell culture passage. Infectious RNA transcripts from HAV cDNA should be useful for studying the molecular basis of cell culture adaptation and attenuation as well as for studying specific viral functions.

Determining the size of non-A, non-B hepatitis virus by filtration

The approximate size of the H strain of non-A, non-B (NANB) hepatitis virus was determined by filtration through polycarbonate membranes. The accuracy and reproducibility of such filtrations were monitored by filtering selected reference viruses. These studies indicate that strain H, representative of the principal blood-borne NANB hepatitis virus, is 30-60 nm in diameter. It is therefore highly unlikely that NANB hepatitis virus is a retrovirus, as has been suggested.

Detection of hepatitis A virus by extraction of viral RNA and molecular hybridization

Hepatitis A virus (HAV) RNA was extracted from cell culture, serum, liver, and feces and then detected by molecular hybridization with cloned HAV cDNA. Hybridization was approximately 10-fold more sensitive than immune electron microscopy or radioimmunoassay was and less sensitive than was assays of HAV infectivity in primates or in cell culture. As little as 10(3) 50% infective doses of HAV, or approximately 0.1 pg of viral RNA, was detected by this method. Analysis of fecal specimens from an experimentally infected marmoset and an epidemic of hepatitis A showed that HAV excretion could often be detected later in the illness by hybridization than by radioimmunoassay. This technique should be widely applicable for detection and analysis of HAV RNA.

Detection of hepatitis B virus DNA in asymptomatic hepatitis B surface antigen carriers: relation to sexual transmission

The authors tested, by molecular hybridization, for hepatitis B virus DNA in serum specimens of 182 asymptomatic hepatitis B surface antigen (HBsAg) Greek carriers who were heterosexual partners of patients with acute hepatitis B (group A: 96 cases) or healthy subjects who were susceptible to hepatitis B (group B: 86 cases). The mean age (34.1 +/- 10.4 vs. 33.9 +/- 8.4 years) and the mean duration of sexual contact (6.9 +/- 8.9 vs. 7.2 +/- 6.3 years) were similar in the two groups of carriers. Hepatitis B virus DNA was detected significantly more frequently in group A than in group B (59.4% vs. 11.6%, p less than 0.001). In particular, in group A, hepatitis B virus DNA was detected in 96.9% of hepatitis B e antigen (HBeAg)-positive and 41% of antibody to HBeAg (anti-HBe)-positive carriers. In contrast, in group B, hepatitis B virus DNA was identified in only 10.8% of anti-HBe-positive carriers (p less than 0.001). These differences were especially significant in the young and middle-aged carriers (16-49 years old) and during the first four years of sexual contact. These data suggest that 1) there is a positive correlation between the presence of hepatitis B virus DNA in serum and the epidemiologic evidence of sexual transmission of hepatitis B virus, 2) hepatitis B virus DNA is a better indicator of infectivity than HBeAg/anti-HBe, and 3) the detection of hepatitis B virus DNA in serum probably identified carriers with high infectivity and potentially higher risk of transmitting hepatitis B virus to their sexual partners.

Hepatitis B virus produced by transfected Hep G2 cells causes hepatitis in chimpanzees

We have reported that clonal cells derived from Hep G2 cells transfected with a plasmid containing hepatitis B virus (HBV) DNA secrete spherical and filamentous forms of hepatitis B surface antigen (HBsAg), core particles, and virions into the culture medium. Here we describe the development of typical hepatitis in two chimpanzees following intravenous inoculation with the medium in which the transfected cells had grown. The liver biopsies from these animals showed characteristic lesions in parenchyma and portal tracts, more conspicuous at an earlier time in the chimpanzee that had received a greater number of virions. The amount of HBsAg in the serum of one infected chimpanzee increased with time after the initial inoculation and then decreased concomitantly with the appearance of antibodies against HBsAg and core antigens. HBsAg remained detectable in the other animal throughout the course of the experiment. The levels of hepatitis B "e" antigen in both animals peaked at week 5, signifying the acute phase of the infection. The activities of serum enzymes that are markers for necroinflammation also increased. The hepatitis HBsAg subtype of the virions isolated from the patient whose DNA was cloned and then used for transfection of the Hep G2 cells was the same as that found in the chimpanzees. Furthermore, the restriction enzyme analysis of the viral DNA isolated from the chimpanzees was identical to the cloned DNA. Thus, HBV DNA-transfected Hep G2 cells can support the replication of virions that, in turn, produce hepatitis in chimpanzees.

Natural history of acute hepatitis B surface antigen-positive hepatitis in Greek adults

We prospectively followed up 821 adults with acute viral hepatitis hospitalized at the Athens Hospital for Infectious Diseases between May 1981 and May 1983. Radioimmunoassays for the detection of serologic markers of hepatitis A virus, hepatitis B virus, and hepatitis delta virus, and molecular hybridization techniques for the detection of serum hepatitis B virus deoxyribonucleic acid and hepatitis delta virus ribonucleic acid were used. Based on the results of an enzyme immunoassay for the detection of immunoglobulin M antibody to hepatitis B core antigen (Corzyme-M), 563 cases were diagnosed as acute hepatitis B and 45 as acute hepatitis superimposed on hepatitis B surface antigen carriage. Development of the hepatitis B surface antigen carrier state was observed in only 1 (0.2%) of the 507 cases with acute hepatitis B that were followed. In contrast, hepatitis B surface antigen persisted in all the latter cases. Acute hepatitis superimposed on hepatitis B surface antigen carriage was attributed to hepatitis A virus superinfection in 2 (4.4%), hepatitis delta virus superinfection in 22 (48.9%), reactivation of chronic type B hepatitis in 12 (26.7%), seroconversion from hepatitis B e antigen-positive to anti-hepatitis B e antibody-positive in 2 (4.4%), presumed superinfection by non-A, non-B agent(s) in 6 (13.4%), and the first clinical manifestation of chronic active hepatitis in 1 (2.2%) case. These data show that acute clinical hepatitis B in adults seems to be a self-limited disease and rarely leads to the development of the carrier state in this epidemiologic setting and hepatitis delta virus superinfection and spontaneous reactivation of chronic hepatitis B are the principal causes of acute hepatitis superimposed in hepatitis B surface antigen carriers in an area with a moderately high prevalence of hepatitis B virus infections.

Complete nucleotide sequence of an attenuated hepatitis A virus: comparison with wild-type virus

The complete nucleotide sequence of an attenuated hepatitis A virus, HAV HM-175/7 MK-5, was determined from cloned cDNA. This virus was derived from wild-type HAV HM-175 after 32 passages in African green monkey kidney cells. The resultant cell culture-adapted virus is attenuated for chimpanzees. This virus was passaged an additional three times in monkey kidney cells to obtain sufficient virus for molecular cloning and was designated HM-175/7 MK-5. Three overlapping cDNA clones were obtained that together spanned the entire genome. Comparison of the nucleotide sequence of cDNA from wild-type virus (propagated in marmoset liver in vivo) with attenuated virus (grown in cell culture) showed 24 nucleotide changes distributed throughout the genome. Five base deletions occurred in the 5' noncoding region, and 12 of the 16 base substitutions in the coding region resulted in amino acid changes. Amino acid changes occurred in viral capsid proteins VP1 and VP2 and several of the nonstructural proteins. Thus, a small number of nucleotide changes are responsible for adaptation to cell culture and attenuation of HAV strain HM-175.

Serological response to the hepatitis delta virus in hepatitis D

Sera from 74 hepatitis B surface antigen-positive individuals, who presented with acute hepatitis delta virus (HDV) infection which ran a self-limited course in 58 and progressed to chronicity in 16, were tested over time for HDV markers. In self-limited disease the serum pattern varied from early HD-antigenaemia followed by IgM and IgG anti-HD seroconversion, to the appearance of IgM and IgG anti-HD without antigenaemia, or the isolated expression of either the IgM or the IgG antibody. The typical case of IgM anti-HD was transient and appeared with a mean delay of 10-15 days from admission in the different serological subgroups. The IgG antibody usually developed several weeks later during convalescence. In contrast, patients with disease destined to become chronic had a brisk IgM antibody response and IgG anti-HD was detectable with a mean delay of 15 days; generally, the IgM and the IgG antibody persisted over the follow-up time. IgM antibody to HDV is often the only serological test positive in the clinical stage of hepatitis D and repeated testing for this marker is necessary to diagnose acute HDV co-infection. The serological follow-up provides important prognostic information: waning of IgM confirms resolution of HDV infection, persistence predicts chronicity.

An epidemic of hepatitis A in an institution for young children

A common-source epidemic of hepatitis A occurred in an Athenian institution boarding 38 children (mean age 4.8 years). All children were examined, and blood was drawn from each at the onset of the study and repeatedly during the next three months. Only one child (2.6%) was initially immune to hepatitis A virus as a result of prior infection. The attack rate (62.2%) and the ratio of icteric to anicteric cases (1:1.3) were high despite the administration of immunoglobulin (IG). Assays for anti-HAV IgM and a rising titer of anti-HAV IgG identified 19 (82.6%) and 22 (95.7%) of the 23 hepatitis A infections, respectively. One case (4.3%) was detected only by the presence of hepatitis A virus antigen and hepatitis A virus RNA in a fecal specimen, but these assays were otherwise marginally useful in this study. Nevertheless, the use of all available tests for the detection of hepatitis A virus is mandatory for the most accurate estimation of an epidemic of hepatitis A. Prompt administration of immunoglobulin had no effect on the number of clinical cases that were in the late incubation period, but it may have diminished the clinical expression of the infection and thus made diagnosis of infection more difficult.

Hepatocarcinogenicity of the woodchuck hepatitis virus

During investigations of the evolution of experimental laboratory infections of woodchucks (Marmota monax) with the woodchuck hepatitis virus (WHV), eight hepatocellular carcinomas (HCC) were observed, six in newborns and two in young adult animals, all within 17-36 months after infection. The absence of an external cocarcinogenic effect in the well-monitored woodchucks indicates the carcinogenicity of WHV and suggests the same for the genetically and biologically similar human hepatitis B virus (HBV). Laboratory infections of woodchucks with two strains of WHV, not reported here in detail, resembled human and chimpanzee HBV infections histologically and serologically. In these studies, eight woodchucks became carriers of surface antigen of WHV for greater than 1 year. All eight woodchucks developed HCC, indicating a 100% risk of HCC in experimentally infected chronic WHV antigen carriers, which is analogous to the high risk of HCC in human hepatitis B surface antigen carriers. Histologically, the absence of cirrhosis in the examined pericarcinomatous tissue permits recognition of gradual transition from normal parenchyma to neoplastic nodules to HCC of rising anaplasia, indicating a continuum of increasingly more malignant neoplastic stages, as known for chemical carcinogenesis. The HCC developed in carrier woodchucks infected as newborns with only minor, if any, hepatitic changes but is associated with antigen-carrying hepatocytes and sometimes with hyperplastic nodules. This stage was preceded in infected adults by an early, acute, weeks-long hepatitis coinciding with the appearance of surface antigen. These findings are also analogous to typical HBV infection in human newborns and young adults, respectively. At the time of HCC development in all animals with adequate histologic material, an acute recent necroinflammation appeared around the tumor, associated with abnormal hematopoietic cells around and within the tumor. A promoting role in carcinogenesis of this necroinflammation of yet unestablished pathogenesis is being postulated, to be confirmed by determination of the status of the WHV DNA in the HCC and by prospective histologic study of the inflammatory reaction.

Titration of the infectivity of hepatitis D virus in chimpanzees

The infectivity of hepatitis D virus (HDV) was evaluated by intravenous inoculation of chimpanzees. HDV was present in the inoculum at a titer of 10(11) chimpanzee infectious doses (CID). In contrast, the titer of hepatitis B virus (HBV) in the same inoculum was 10(6) CID. All HBV-infected chimpanzees inoculated with less than or equal to 10(-11) dilutions of the HDV-positive plasma were superinfected; an animal receiving a 10(-12) dilution did not develop markers of HDV replication in serum or liver. All HDV-infected chimpanzees had marked elevations of serum alanine aminotransferase activities. The incubation period from exposure to development of hepatitis was inversely related to the dose of HDV inoculum, although the severity and duration of hepatitis were independent of it. All animals recovered and rapidly developed antibody to hepatitis D antigen.

Complete nucleotide sequence of wild-type hepatitis A virus: comparison with different strains of hepatitis A virus and other picornaviruses

The complete nucleotide sequence of wild-type hepatitis A virus (HAV) HM-175 was determined. The sequence was compared with that of a cell culture-adapted HAV strain (R. Najarian, D. Caput, W. Gee, S.J. Potter, A. Renard, J. Merryweather, G.V. Nest, and D. Dina, Proc. Natl. Acad. Sci. USA 82:2627-2631, 1985). Both strains have a genome length of 7,478 nucleotides followed by a poly(A) tail, and both encode a polyprotein of 2,227 amino acids. Sequence comparison showed 624 nucleotide differences (91.7% identity) but only 34 amino acid differences (98.5% identity). All of the dipeptide cleavage sites mapped in this study were conserved between the two strains. The sequences of these two HAV strains were compared with the partial sequences of three other HAV strains. Most amino acid differences were located in the capsid region, especially in VP1. Whereas changes in amino acids were localized to certain portions of the genome, nucleotide differences occurred randomly throughout the genome. The most extensive nucleotide homology between the strains was in the 5' noncoding region (96% identity for cell culture-adapted strains versus wild type; greater than 99% identity among cell culture-adapted strains). HAV proteins are less homologous with those of any other picornavirus than the latter proteins are when compared with each other. When the sequences of wild-type and cell culture-adapted HAV strains are compared, the nucleotide differences in the 5' noncoding region and the amino acid differences in the capsid region suggest areas that may contain markers for cell culture adaptation and for attenuation.

Fulminant hepatitis in asymptomatic hepatitis B surface antigen carriers in Greece

Eleven male fulminant hepatitis (FH) patients (mean age: 47.7 +/- 16 years) positive for hepatitis B surface antigen (HBsAg) but negative for IgM antibody to hepatitis B core antigen (IgM anti-HBc) were admitted consecutively to the Athens Hospital for Infectious Diseases between May 1981 and November 1983. Because of the absence of IgM anti-HBc, determined by an enzyme immunoassay, these patients were considered to be HBsAg carriers with a superimposed acute hepatitis. Three of the 11 patients received immunosuppressive chemotherapy during the six months before the onset of the acute hepatitis. None of the patients was homosexual or a drug addict. Infection with hepatitis A virus (HAV), hepatitis B virus (HBV), or hepatitis delta virus (HDV) was detected with serologic markers and/or molecular hybridization techniques. Fulminant hepatitis was attributed to spontaneous reactivation of chronic hepatitis B in four patients, chemotherapy-induced reactivation of chronic hepatitis B in three patients, HDV superinfection in one patient and possible superinfection by non-A, non-B agent(s), HDV, or HDV-like agents in three patients. Reactivation of chronic hepatitis B was an important cause of apparent acute hepatitis in heterosexual male HBsAg carriers from an area with a high prevalence of HBV infection.

Failure to detect polyalbumin-binding sites on the woodchuck hepatitis virus surface antigen: implications for the pathogenesis of hepatitis B virus in humans

Binding sites for polymerized albumin on hepatitis B virus components were reported in human hepatitis B virus chronic carriers predominantly with active viral replication (HB e antigen positive). The presence of comparable albumin-binding sites in the woodchuck hepatitis virus (WHV) model was examined on WHV components obtained from woodchucks with active viral replication (DNA polymerase positive). Binding sites for polymerized woodchuck serum albumin were not detected on the intact WHV virion, on 22-nm woodchuck hepatitis surface antigen (WHsAg), or on WHsAg polypeptides. Woodchuck albumin was not detected in purified 22-nm WHsAg, and anti-albumin antibodies were not detected in WHV chronic-carrier woodchucks. Our results in the WHV model argue against a role for viral polyalbumin-binding sites in tissue- and host-specific virus infectivity.

Protection of chimpanzees from type B hepatitis by immunization with woodchuck hepatitis virus surface antigen

Two chimpanzees immunized with woodchuck hepatitis virus (WHV) surface antigen (WHsAg) developed antibodies cross-reactive with hepatitis B virus (HBV) surface antigen (HBsAg). After challenge with HBV, one animal was completely protected and the other experienced a subclinical infection, without evidence of liver disease. Three woodchucks immunized with HBsAg developed antibodies to HBsAg which did not cross-react with WHsAg. After challenge with WHV, all three woodchucks developed typical acute infections with associated hepatic lesions. Serological studies with the cross-reactive antibodies raised in chimpanzees suggested that the protective epitopes of WHsAg were related to the group a specificity of HBsAg. These studies indicated that cross-protective epitopes are shared by HBV and WHV; however, the humoral response to these epitopes can vary among species.

Epidemiologic aspects of Santa Marta hepatitis over a 40-year period

"Santa Marta" hepatitis has been recognized as an unusual type of severe hepatitis occurring in northern Colombia since 1930. Liver specimens from a historic viscerotomy series, used by Gast-Galvis to identify cases and describe epidemiologic features of this disease, were available for review and histopathologic staining for delta-virus. Of 86 liver specimens examined from cases of fulminant Santa Marta hepatitis, 81 showed a distinct histopathologic picture, in various stages of progression, with features of eosinophilic necrosis, microvesicular fat infiltration of the liver parenchyma and morula cells; 69% were positive for delta-antigen by immunoperoxidase staining. This disease occurred predominantly in several small towns within 50 km of Santa Marta, with mortality reaching 1.25 per 1,000 inhabitants per year during the 1940's. Children under age 15 were most commonly affected and males affected twice as frequently as females. Liver specimens obtained from children, or within 15 hr of death, or which showed early histologic stages of disease were most likely to be positive for delta-antigen. This and the accompanying study confirm the existence of a distinct type of fulminant hepatitis in Colombia for over 50 years. The epidemiologic and histopathologic features are comparable to severe hepatitis in Venezuela Indians and in the Amazon basin of Brazil, suggesting that all are caused by delta-superinfection of hepatitis B virus carriers.

Specific histologic features of Santa Marta hepatitis: a severe form of hepatitis delta-virus infection in northern South America

Stimulated by observations in an outbreak of hepatitis delta-virus infection among Yucpa Indians in Venezuela, in which unusual histologic features were found, we studied 100 cases of fatal hepatitis from Colombia, South America, which had been obtained by autopsy or viscerotomy. These cases were considered to be "Santa Marta hepatitis," or "hepatitis of the Sierra Nevada de Santa Marta," which has been observed in this region for more than 40 years. Of the 100 cases, 19 had a variety of histologic lesions or were normal, and hepatitis delta-virus antigen was not demonstrated immunocytochemically in any of them. By contrast, 81 cases had a characteristic histologic picture with intense microvesicular steatosis associated with conspicuous eosinophilic necrosis of the hepatocytes, which apparently were sluggishly removed by cytolysis. Hepatitis delta-virus antigen was detected in 70% of the 81 cases, and the absence of detection of this antigen was often associated with poor tissue preservation and more extensive hepatocyte necrosis. A smaller percentage of patients had hepatitis B virus antigens detectable in liver tissue. The characteristic lesion in these 81 cases could be distinguished from other causes of microvesicular steatosis by the extensive eosinophilic necrosis. Other variable accompanying features included intraacinar, mainly macrophagic, scavenger cell inflammation, intense portal inflammation, a parenchymal regeneration, and ductular and arteriolar proliferation. Santa Marta hepatitis as a severe form of hepatitis delta-virus infection differs markedly from fulminant delta-hepatitis in Europe and the United States in which the microsteatosis with marked eosinophilic degeneration is not found. The causes for these differences are unknown but may relate to nutritional factors or environmental toxins.(ABSTRACT TRUNCATED AT 250 WORDS)

Further studies by immunofluorescence of the monoclonal antibodies associated with experimental non-A, non-B hepatitis in chimpanzees and their relation to D hepatitis

To further investigate the specificity of the monoclonal antibodies (48-1 and S-1) associated with non-A, non-B hepatitis, extensive immunofluorescence studies were performed on liver biopsy specimens from chimpanzees with experimental hepatitis A, B, non-A, non-B or delta, or from normal chimpanzees. Both 48-1 and S-1 antibodies reacted in the same manner with liver biopsy specimens from 47 of 50 (94%) chimpanzees with acute or chronic non-A, non-B hepatitis and 15 of 18 (83%) chimpanzees with type D hepatitis. Examinations of serial liver biopsy specimens revealed that the duration of expression of the antigen reacting with the antibodies in hepatocytes of chimpanzees infected with non-A, non-B viruses appeared to be longer than that of chimpanzees infected with the hepatitis delta-virus. By thin-section electron microscopy, the presence of the microtubular aggregates, identical to those previously described for chimpanzees with non-A, non-B hepatitis and shown by immunoelectron microscopy to react with the antibodies, was noted in hepatocytes during the acute phase of hepatitis delta-virus. The antibodies did not react with liver biopsy specimens from chimpanzees acutely or chronically infected with hepatitis B virus or hepatitis A virus, or from normal chimpanzees. The present results confirm our previous observations with the 48-1 and S-1 antibodies. Furthermore, the finding that these two antibodies were also associated with hepatitis D would support the possibility that non-A, non-B agents and the hepatitis delta-virus may have a similar nature or may elicit a similar host response.

Type D hepatitis: the clinical significance of hepatitis D virus RNA in serum as detected by a hybridization-based assay

Hepatitis D virus is a defective human pathogen that requires hepatitis B virus for its replication. A hybridization-based assay for the 1.75 kb RNA genome of hepatitis D virus was developed using as probe a radiolabeled transcript of a cloned cDNA fragment (pKD3 hepatitis D virus DNA). Sera from 120 chronic carriers of HBsAg with confirmed hepatitis D virus infection were analyzed for the presence of hepatitis D virus RNA. Serum hepatitis D virus RNA was detected in 43 of 74 (58%) patients with chronic liver disease; some patients were positive for hepatitis D virus RNA in multiple samples over a period of several years. Serum hepatitis D virus RNA was present in 17 of 28 (61%) patients during the acute phase of clinical hepatitis and was not detected after recovery from acute disease or in 18 asymptomatic chronic HBsAg carriers with antibody to hepatitis D virus. The presence of hepatitis D virus RNA correlated with other known markers of active hepatitis D virus replication; all chronic active liver disease patients with serum hepatitis D virus RNA were positive for antihepatitis D antigen IgM, and 34 of 37 (92%) had hepatitis D antigen in their liver biopsy specimens. The assay for hepatitis D virus RNA provides a direct and noninvasive method for the detection of hepatitis D virus in serum and will be useful in the study of the natural history of type D hepatitis, the identification of chronic hepatitis D virus carriers likely to transmit hepatitis D virus and the selection and monitoring of patients for potential antiviral therapy.

Detection of a genome-linked protein (VPg) of hepatitis A virus and its comparison with other picornaviral VPgs

The nucleotide sequence corresponding to the P3 region of the hepatitis A virus (HAV) polyprotein genome was determined from cloned cDNA and translated into an amino acid sequence. Comparison of the amino acid sequences of the genome-linked proteins (VPgs) of other picornaviruses with the predicted amino acid sequence of HAV was used to locate the primary structure of a putative VPg within the genome of HAV. The sequence of HAV VPg, like those of other picornaviral VPg molecules, contains a tyrosine residue as a potential binding site for HAV RNA in position 3 from its N terminus. The potential cleavage sites to generate VPg from a putative HAV polyprotein are between glutamic acid and glycine at the N terminus and glutamic acid and serine or glutamine and serine at the C terminus. A synthetic peptide corresponding to 10 amino acids of the predicted C terminus of HAV VPg induced anti-peptide antibodies in rabbits when it was conjugated to thyroglobulin as a carrier. These antibodies were specific for the peptide and precipitated VPg, linked to HAV RNA, from purified HAV and from lysates of HAV-infected cells. The precipitation reaction was blocked by the synthetic peptide (free in solution or coupled to carrier proteins) and prevented by pretreatment of VPg RNA with protease. Thus, our predicted amino acid sequence is colinear with the nucleotide sequence of the VPg gene in the HAV genome. From our results we concluded that HAV has the typical organization of picornavirus genes in this part of its genome. Similarity among hydrophobicity patterns of amino acid sequences of different picornaviral VPgs was revealed in hydropathy plots. Thus, the VPg of HAV appears to be closely related to VPg1 and VPg2 of foot-and-mouth disease virus. In contrast, HAV VPg has a unique isoelectric point (pI = 7.15) among the picornavirus VPgs.

Significance of IgM antibody to hepatitis B core antigen in a Greek population with chronic hepatitis B virus infection

IgM antibody to hepatitis B core antigen (IgM anti-HBc) may indicate an active immune response to persistent infection with hepatitis B virus (HBV). We studied 186 Greek HBsAg carriers for IgM anti-HBc and attempted to correlate it with other HBV and hepatitis delta virus (HDV) markers. Overall, IgM anti-HBc was detected more frequently than HBV DNA in this population (50% vs 34, p less than 0.001); this was also true for the 149 of the 186 HBsAg carriers with antibody to hepatitis B e antigen (anti-HBe) (48% vs 22%, p less than 0.001). The opposite was found in the carriers positive for hepatitis B e antigen (HBeAg): HBV DNA was observed in 93% and IgM anti-HBc in 64% of the cases (p less than 0.05). The detection of these markers was independent of sex. Serum alanine aminotransferase (ALT) levels were significantly more elevated in patients with positive tests for IgM anti-HBc and HBV DNA than in patients positive only for HBV DNA (p less than 0.001) irrespective of their HBeAg or anti-HBe status. Moreover, the detection of elevated ALT was independent of the intensity of the HBV DNA hybridization signal. Antibodies to hepatitis delta antigen (HDAg) were only found in 4 (2.4%) of 167 patients tested.

Inactivation of human T-cell lymphotropic virus, type III by heat, chemicals, and irradiation

Infectivity of human T-cell lymphotropic virus, Type III (HTLV-III) was inactivated by heat more rapidly if in liquid medium than if lyophilized and more rapidly at 60 degrees than 56 degrees C. When HTLV-III was added to factor VIII suspension, then lyophilized and heated at 60 degrees C for 2 hours or longer there was elimination of 1 X 10(6) in vitro infectious units (IVIU) of virus. Much of the viral inactivation appeared to result from lyophilization. The application of water-saturated chloroform to the lyophilized material containing virus also resulted in elimination of infectivity. HTLV-III was efficiently inactivated by formalin, beta-propiolactone, ethyl ether, detergent, and ultraviolet light plus psoralen. The results are reassuring regarding the potential safety of various biological products.

Fecal excretion of Greek strains of hepatitis A virus in patients with hepatitis A and in experimentally infected chimpanzees

The presence of hepatitis A virus (HAV) in stool samples was determined in 36 children (mean age, 8.9 years) and 38 adults (mean age, 19.9 years) with acute type A hepatitis. Three stool samples, taken on admission and thereafter at three-to-five-day intervals, were collected from each patient. The first day of dark urine was considered to be the onset of illness. Molecular hybridization of cloned HAV cDNA to fecal extracts was used to detect HAV RNA; radioimmunoassay was used to detect HAV antigen. In all of the samples tested, HAV RNA was detected significantly more frequently than HAV antigen (28.4% vs. 8.1%, P less than .001). HAV RNA was detected with equal frequency in both children and adults during the first week of illness. However, HAV RNA was detected more frequently in children than in adults during the second week of illness (45.7% vs. 18.9%, P less than .05). Among patients with HAV RNA, detection in multiple samples was more frequent in children than in adults (38.9% vs. 7.9%, P less than .01), especially among males.