Characterization of hepatitis E virus (HEV) from Algeria and Chad by partial genome sequence

The purpose of this study was to analyze partial nucleotide sequences and derived peptide sequences of hepatitis E virus (HEV) from two outbreaks of hepatitis E in Africa (Chad 1983-1984; Algeria 1978-1980). A portion of ORF3 and the major portion of ORF2 were amplified by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). The PCR products were sequenced directly or after cloning into the pCRII vector. Sequences were then compared to the corresponding regions of reported full length HEV sequences. In the ORF2 and ORF3 regions, the homology between the Algerian and the Chad isolates at the nucleic acid level was 92 and 95%, respectively. At the peptide level the homology was 98% in both regions. In these regions, both strains are more related to Asian strains at the nucleic acid level (89 to 95%) and at the amino acid level (95 to 100%) than to the Mexico strain. At the peptide level the differences are less apparent. Both African isolates have amino acid changes in common with some reference strains although the Chad isolate has three unique changes. These African strains of HEV, based on the ORF2 and ORF3 phylogenetic trees, appear to be a distinct phylogenetic group, separate from the Mexican and Asian strains.

African strains of hepatitis E virus that are distinct from Asian strains

Partial genomic sequences of four hepatitis E virus (HEV) strains from Africa (Morocco and Tunisia) and one from Central Asia (Tashkent, Uzbekistan) were obtained. The reverse transcriptase-polymerase chain reaction was used to amplify 5' and hypervariable regions of open reading frame 1 (ORF1) and a region overlapping all 3 ORFs. Sequence analysis of these regions revealed the African strains to be quite distinct from all known Asian strains but more similar to them than to the Mexican strain. Sequence analysis of the Tashkent strain revealed almost complete identity with another central Asian strain from Osh, Kirgizia. These results thus further confirm the geographical origin of HEV strain divergence.

Detection of antibodies to hepatitis E virus in patients with autoimmune chronic active hepatitis and primary biliary cirrhosis

BACKGROUND

Viral hepatitis E (HIV) frequently causes epidemic outbreaks in many developing countries. It is also present in developed countries as imported cases. The role of hepatitis A virus as trigger for autoimmune chronic hepatitis has been demonstrated, and it has been suggested that this may also apply to HEV.

METHODS

The presence of anti-HEV antibodies in serum samples from patients with autoimmune chronic active hepatitis (n = 52) and with primary biliary cirrhosis (n = 25) was investigated using an Abbott assay and a peptide-based test.

RESULTS

Anti-HEV antibodies were detected with the Abbott test in 13% (7 of 52) of the patients with autoimmune chronic active hepatitis, but not of these were positive in the synthetic peptide-based test.

CONCLUSION

These findings indicate the HEV is not associated with primary biliary cirrhosis but may be implicated in some cases of autoimmune chronic active hepatitis.

Cell mediated immunity induced in mice by HPV 16 L1 virus-like particles

Recombinant human papillomavirus (HPV) type 16 L1 virus-like particles (VLPs) expressed in the baculovirus system were used to investigate the cellular immune response to human papillomavirus type 16. The cell-mediated immune response was evaluated through immunization of mice with HPV 16 L1 virus-like particles using a lymphoproliferation assay and cytokine production and cytometric analysis of lymphocyte subsets. A significant proliferative response was observed which was associated with secretion of both interferon-gamma and interleukin-2. FACS analysis of splenic lymphocytes revealed that CD8+ T-cells were increased in the immunized mice. These results demonstrate that HPV 16 L1 VLPs induce a T-cell response characterized by a Th1 profile and confirm that the HPV 16 VLP is a reasonable candidate for vaccine development.

Detection by PCR of human papillomavirus genotypes in cervical lesions of Senegalese women

In order to analyse human papillomavirus (HPV) infection in the Senegalese population, HPV DNA was sought in 65 women with evidence of cervical cytological abnormality and in 72 pregnant women. Ninety-four percent of the patients were positive for HPV DNA as compared to 24% of pregnant women. HPV 16 was detected in cervical smears in 42% of cases, HPV 18 in 39%, HPV 6 in 26%, HPV 11 in 15%, HPV 45 in 10%, HPV 52 in 3%, and HPV 31, HPV 33 and HPV 68 in 1.5%. HPV 16 and HPV 18 were detected in 16% and 7% respectively of pregnant women. HPV DNA of unknown type was detected in 6% of cases, and multiple HPV infections were observed in 28% of cases. Low risk genital HPVs (6/11) were detected in smaller proportions (17%) among high grade squamous intraepithelial lesions (SILs) than the low grade SILs (43%). High risk HPVs (16/18) were detected in high proportions both in low and high grade SIL lesions, though the highest frequency (70%) was observed among patients with high grade lesions. In conclusion, the results confirm that HPV infections are frequent in Senegal and that HPV 18 and 45 are detected in a high proportion of patients in Africa.

Production of human papillomavirus type 45 virus-like particles in insect cells using a recombinant baculovirus

The L1 major capsid protein of human papillomavirus type 45 was expressed in insect cells using recombinant baculovirus technology. Human papillomavirus type 45 L1 major capsid protein self-assembled into empty virus-like particles (VLPs). These 50-60 nm diameter particles were present in the nuclei of recombinant baculovirus-infected insect cells and had a density of 1.29 - 1.30 g/cm3 in cesium chloride. The expressed human papillomavirus type 45 L1 protein sequence is identical to the reference human papillomavirus type 45 strain except for one amino acid located at position 49 of the human papillomavirus type 45 L1 protein. It must be noted that the quantity of purified human papillomavirus type 45 virus-like particles is at a lower level than that previously observed with human papillomavirus type 16. Nevertheless, the ability to generate preparative amounts of human papillomavirus type 45 virus-like particles is of great importance for the production of an anti-human papillomavirus vaccine.

Short report: polymerase chain reaction detection of hepatitis E virus in north African fecal samples

Epidemics of enterically-transmitted non-A, non-B hepatitis were described in 1983-1984 involving French soldiers in Chad and in 1979-1980 in residents of Algeria. Hepatitis E virus (HEV) was subsequently implicated by serology. In this study, the presence of HEV in patient stool specimens from both outbreaks and from sporadic cases in residents of Chad (1994) was documented. This virus was detected in fecal suspensions by antibody capture of the virus and reverse transcriptase-polymerase chain reaction amplification of the viral RNA in the 3' end of open reading frame 2. Two of five epidemic cases from Chad (1983-1984) were positive, as well as one of five sporadic cases from Chad (1994), and two of three epidemic cases from Algeria (1979-1980). Of these 13 patients, 12 had detectable anti-HEV IgG in their serum. These results confirmed that HEV was the cause of hepatitis in at least five of these 13 patients.

Detection of antibodies against human papillomavirus (HPV) type 16 virions by enzyme-linked immunosorbent assay using recombinant HPV 16 L1 capsids produced by recombinant baculovirus

The L1 major capsid protein of human papillomavirus type 16 (HPV-16) was expressed in Sf-21 insect cells with a recombinant baculovirus. Virus-like particles obtained were purified and used to develop an enzyme-linked immunosorbent assay for detection of anti-HPV-16 antibodies in sera from 76 women with evidence of genital HPV infection and 79 controls. HPV-16-infected individuals developed antibodies directed at HPV-16 virions since reactivity against recombinant HPV-16L1 capsids was observed in 50% of them compared with only 6% in the general adult population. However, some cross-reactivities with sera from women infected with others HPV types were observed.

Detection of antibodies to L1, L2, and E4 proteins of human papillomavirus types 6, 11, and 16 by ELISA using synthetic peptides

Antibodies against eight synthetic peptides spanning different epitopes located on L1, L2, and E4 proteins of human papillomavirus (HPV) types 16, 6, and 11 were examined in sera from 73 women infected by HPV and from 139 healthy controls. Only three of these peptides were reactive. Two located on proteins L2 and E4 of HPV 16 seem type specific since antibodies to these peptides were detected, respectively, in 21% and 15% of the HPV 16 infected patients and in 2.5% and none of women infected by other HPVs. The third peptide located on the L1 protein of HPV 6 bears a common epitope since antibodies to this peptide were detected not only in 85% of women infected by HPV 6 or 11, but also in 82% of women infected by other HPVs, and in 74% and 71% of the control groups (10-12-year-old children and adults, respectively). In conclusion, none of the peptides investigated seems useful to develop ELISAs for serological diagnosis of HPV infection.

Etiology of acute sporadic hepatitis in adults in Senegal and Tunisia

Markers for acute hepatitis A, B, C and E virus infections were examined in the sera of 72 patients suffering from acute hepatitis in Senegal and Tunisia. Hepatitis B was responsible for 36% and hepatitis C for 21% of the cases. Acute hepatitis A was not diagnosed. HEV infection was not observed in Senegal and represents only 4% of the acute hepatitis cases in Tunisia.

Simultaneous injection of plasma-derived or recombinant hepatitis B vaccines with yellow fever and killed polio vaccines

Previous studies have shown an absence of interaction between hepatitis B (HB) vaccine and other vaccines used in EPI programmes except for an apparent decrease of yellow fever antibody levels when hepatitis B and yellow fever vaccines are given simultaneously. We have therefore reinvestigated the interaction of these two vaccines and assessed the absence of interaction between inactivated polio vaccine and recombinant or plasma-derived HB vaccine. The immune responses to polio vaccine injected simultaneously with plasma-derived or recombinant HB vaccine were observed to be equivalent and similar to those observed in the literature. In this randomized study, the immune responses to yellow fever injected simultaneously with plasma-derived or recombinant HB vaccine were comparable to those observed after separate administration of each vaccine. Moreover, no increase in adverse reactions was noted.

Twelve-year follow-up study of hepatitis B immunization of Senegalese infants

Numerous studies have documented the efficacy and safety of plasma-derived and recombinant hepatitis B vaccines. However, little is known about the long-term protection of hepatitis B vaccine, when anti-HBs declines to low or undetectable levels. This study reports results from a 9-12-year period follow up of infants immunized against hepatitis B in Senegal. At the end of the follow-up period anti-HBs were detected in 81% of children who received a booster dose at school age and in 68% of those who did not. HBsAg was detected in 19% of infants from the control group compared to only 2% of immunized infants, corresponding to a protective efficacy of 88%. The results show that long-term protection against HBsAg carriage of hepatitis B vaccination is very high and that a booster dose at school age does not significantly increase this protection.

Self-assembly of human papillomavirus type 16 capsids by expression of the L1 protein in insect cells

The L1 major protein of human papillomavirus type 16 was expressed in Sf-21 insect cells with a recombinant baculovirus vector. Virus-like particles similar in appearance to empty virions were identified by electron microscopy at densities of 1.29-1.30. Purified particles reacted with monoclonal anti-HPV-16-L1 antibody in Western blot and immuno dot blot suggesting that conformational epitopes are present in the recombinant particles. Immunodot blot assays using human sera correlated with the detection of HPV-16 DNA by the polymerase chain reaction. The results suggest that HPV-16-L1 virions produced by the baculovirus system might be useful for developing serologic tests to measure antibodies to conformational epitopes and may offer potential for vaccine development.

Familial clustering of hepatitis B virus infections and prevention of perinatal transmission by immunization with a reduced number of doses in an area of intermediate endemicity (Tunisia)

Hepatitis B surface antigen (HBsAg) was detected in 3.3% of 7162 pregnant Tunisian women tested and HBeAg in 9.6% of the HBsAg-positive mothers. Family members of 46 of these HBsAg-positive mothers (33 husbands and 61 children aged 1-6 years) were investigated for the presence of HBV markers. HBsAg was detected in 21% of the children and 18% of the husbands. Fifty children born to HBsAg-positive mothers received hepatitis B vaccine at birth, at the age of 2-3 months and at the age of 9 months. After immunization, anti-HBs were detected in 92% of them with an anti-HBs geometric mean titre of 415 mIU ml-1. Compared with the HBsAg carrier state in older siblings, the protective efficacy was estimated to be 60%. It was 100% for infants born to HBeAg-negative mothers, but only 31% for those born to HBeAg-positive mothers. For a better efficacy, the schedule of the EPI needs to be modified to include an immunization session at 1 month of age.

Cell abnormalities associated with human papillomavirus-induced squamous intraepithelial cervical lesions. Multivariate data analysis

One hundred ninety-six cervical scrapings were obtained for simultaneous research of cell abnormalities in Papanicolaou smears and detection of genital human papillomavirus (HPV) genotypes by polymerase chain reaction in extracted DNA from each clinical sample. The samples described by six discriminant cytologic parameters, and a synthetic HPV-presence/absence parameter provided an efficient matrix for multiple correspondence analysis. This statistical analysis displayed a plurality of HPV-related cell abnormalities in squamous intraepithelial lesions, and a high correspondence between HPV infection and the presence of multinucleated squamous cells, morphologically transformed keratinocytes (dyskaryotic cells), koilocytes, and cellular changes related to epithelial maturation. Because of the low proportion of detectable koilocytes in the HPV-infected scrapings, the authors also inferred that cellular changes related to epithelial maturation and morphologically transformed keratinocytes are the most accurate and efficient cell abnormalities, in terms of frequency and correlation, for cytodiagnosis of HPV-induced or associated squamous intraepithelial cervical lesions.

Hepatitis type E in a French population: detection of anti-HEV by a synthetic peptide-based enzyme-linked immunosorbent assay

Four synthetic peptides were used to develop an ELISA for detecting hepatitis type E infections. Antibodies to HEV were detected in 54 of 64 patients present during two outbreaks previously recognized as being due to hepatitis E virus. Those patients included French soldiers stationed in Chad at the time, and Algerian civilians residing in Algeria and considered as positive controls. Anti-HEV were also detected in 3 out of 74 cases of sporadic non-A, non-B, non-C hepatitis in France, and in 2 out of 150 anti-HAV-IgM-positive sporadic cases, also in France, but in none of 278 healthy adults from the general French population. Among a total of 34 anti-HEV-positive cases in French subjects, 32 were shown to be associated with travel outside of western Europe; in two cases, however, HEV transmission appeared to have taken place in Europe. Using this ELISA, a rapid drop in anti-HEV antibodies to undetectable levels following the acute phase of the disease was observed in a high proportion of the infected subjects. Thus, the present test would appear to be more suitable for diagnostic purposes than for epidemiological investigations.

High prevalence of mutations at codon 249 of the p53 gene in hepatocellular carcinomas from Senegal

In hepatocellular carcinoma, mutation within the p53 gene occurs mainly at codon 249 and its frequency has been associated with exposure to aflatoxin. As Senegal is a country where liver cancer incidence is one of the highest in the world and where people are highly exposed to aflatoxin, we screened 15 liver cancer samples from this country for mutation at codon 249 of the p53 gene. Non-tumoral DNA from the patients showed a wild type genotype. Mutation at codon 249 of the p53 gene was detected in 10 of the 15 tumour tissues tested (67%). This frequency of mutation in codon 249 of the p53 gene is the highest described. These results confirmed that there is an association between countries of high aflatoxin intake and a high frequency of mutation in codon 249 of p53 gene, and that HBV alone does not contribute to these base changes.

Random-effects models, for longitudinal data using Gibbs sampling

Analysis of longitudinal studies is often complicated through differences amongst individuals in the number and spacing of observations. Laird and Ware (1982, Biometrics 38, 963-974) proposed a linear random-effects model to deal with this problem. We propose a generalisation of this model to accommodate multiple random effects, and show how Gibbs sampling can be used to estimate it. We illustrate the methodology with an analysis of long-term response to hepatitis B vaccination, and demonstrate that the methodology can be easily and effectively extended to deal with censoring in the dependent variable.

Mapping of linear B cell epitopes on open reading frames 2- and 3-encoded proteins of hepatitis E virus using synthetic peptides

Hepatitis E virus (HEV) is the causative agent of non-A, non-B hepatitis which is transmitted by the fecal-oral route and occurs principally in the form of large epidemics and outbreaks in developing countries. Two overlapping synthetic peptides corresponding to overlapping DNA sequences of the ORF 3 of HEV genome were found to be immunoreactive with sera from patients involved in two epidemics of enterically transmitted non-A, non-B hepatitis. The results suggested the existence of two distinct epitopes. The four synthetic peptides representing these two epitopes from Burma and Mexico strains of hepatitis E virus, were used to investigate anti-HEV reactivities. HEV antibodies were detected in 84-88% of HEV-infected individuals according to the peptide used. The results suggest that a peptide-based ELISA can provide an accurate tool for the diagnosis of acute hepatitis type E.

Hepatitis E and hepatitis C virus infections among French soldiers with non-A, non-B hepatitis

Serologic markers of HCV and HEV were investigated in 74 French soldiers with non-A, non-B hepatitis and in 18 patients involved in an outbreak of non-A,non-B hepatitis in Algeria. Moreover, anti-HCV antibodies were detected in 13 patients with non-A,non-B hepatitis of parenteral origin. HEV antibodies were investigated in 61-65% of patients involved in the 2 enterically transmitted outbreaks of non-A,non-B hepatitis observed in Algeria and Chad. The third cluster of non-A,non-B hepatitis observed in French soldiers serving in French Guyana is more likely to be attributed to malaria prophylactic treatment with Amodiaquine than to a viral origin. HCV infection was observed in 93% of acute or chronic cases associated with blood transfusion or parenteral drug abuse. Among acute cases, none of the soldiers who contracted the disease in Africa or in French Guyana was found to be anti-HCV positive compared to 78% of those who contracted the disease in France. HCV infections resulted in chronic hepatitis in 61% of cases.