To define protein folding patterns of HIV-1 Env subunit vaccines, we have isolated a set of 30 monoclonal antibodies (MAbs) from BALB/c mice immunized with a recombinant gp160 vaccine (rgp160) expressed in a baculovirus system. This article describes epitope mapping for the MAb panel and topology of the epitopes for rgp160 and a recombinant gp120 (rgp120) also expressed in a baculovirus system. The following results are reported: (1) rgp160 harbors a minimum of 4 antigenic domains, 3 mapping to the C1, C2, and C3/V4 regions of gp120 and 1 mapping to the cytoplasmic tail of gp41; (2) there are at least 3 adjacent or overlapping epitopes in each antigenic domain; (3) a minimum of 14 independent epitopes were mapped, all of which are continuous sites; (4) each of the epitopes is exposed on rgp160 without prior manipulation of the protein; and (5) by contrast, 6 of the 8 epitopes mapping to the C1, C2, and C3/V4 regions are not exposed on rgp120, but become exposed when the protein is denatured. Taken together, these results show that rgp160 and rgp120 are folded differently, illustrating the use of this MAb panel to compare epitope topographies of recombination HIV-1 Env proteins. This MAb panel may aid in the refinement of HIV-1 Env subunit vaccines.
The distribution of hepatitis C virus (HCV) genotypes was investigated in 89 HCV-infected Turkish patients. Blood samples were collected from haemodialysis patients (n = 45), chronic liver disease (CLD) patients (n = 38), acute non-A, non-B (NANB) hepatitis patients (n = 2) and blood donors (n = 4). HCV RNA sequences were amplified in the 5' non-coding region and were typed by restriction fragment length polymorphism analysis. The predominant genotype was 1b (75.3%), followed by 1a (19.1%), 2 (3.4%) and 4 (2.2%). While there was no significant difference in the distribution of HCV genotypes with respect to age, sex, transfusion history, alanine aminotransferase levels or liver histology (in the CLD group), type 1a-infected patients were younger than type 1b-infected patients (P < 0.05) in the haemodialysis group. Serological reactivity to recombinant HCV proteins was assessed in 58 samples using the Chiron RIBA-2 assay. The reactivity of samples from patients infected with type 1b with 5-1-1 and c100 antigens was significantly lower (P < 0.05) than the reactivity of samples from those infected with type 1a. These results, together with the results of two previous studies, indicate that HCV genotypes 1, 2, 3 and 4 are prevalent in different frequencies in the Turkish population. Determination of the genotype distribution of HCV in a geographical area may provide important clues for studying the epidemiology, transmission and pathogenesis of HCV-related diseases and may also aid in improving serological assays to detect HCV infection.
Naturally occurring YMDD motif variants were detected at a high rate in a group of lamivudine-untreated inactive HBV carriers.
Our data complement the findings that genotype D viruses are prevalent in the Turkish population. Being rapid and inexpensive, restriction enzyme analysis described in this study should be useful for large-scale epidemiological analysis of HBV infections.
It is estimated that 130-210 million people worldwide are chronically infected with the hepatitis C virus (HCV). Complications of chronic liver disease, like cirrhosis with or without hepatocellular carcinoma, will develop over many years in around 20% of these patients, making HCV infections a major public health issue (1).HCV has six major genotypes and more than 80 subtypes (2). Recently a seventh genotype was proposed (3). Genotypes may differ in their epidemiology, pathogenesis, and response to treatment (4). Type 1, 2, and 3 HCV infections are common throughout the world. Type 4 is prevalent in the Middle East and Africa and responsible for more than 80% of all HCV infections in some countries (5). Genotypes 5 and 6 are mainly found in South Africa and in Southeast Asia, respectively (6). Sustained virological response to standard pegylated interferon plus ribavirin treatment is usually lower for types Background/aim: The frequency of genotype 4 hepatitis C virus (HCV) infections is significantly higher in Kayseri compared to other provinces in Turkey. We aimed to characterize genotype 4 infections in Kayseri by analyzing the demographic and laboratory data of 218 HCV RNA-positive, treatment-naive patients admitted to the Kayseri Training and Research Hospital in 2010 and 2011. Materials and methods:The distributions of sex, age, and viral loads of these patients with respect to HCV genotypes were analyzed. We also characterized the type 4 sequences at the subtype level. Randomly selected sera from 32 of the 72 genotype 4 patients from this cohort were subjected to PCR amplification in the NS5B region and further characterized by sequencing and phylogenetic and molecular clock analysis.Results: Distribution rates of HCV genotypes 1, 4, and 2 in the 218 patients were 62.4%, 33.0%, and 4.6%, respectively. Most of the patients infected with types 1 and 4 were over the age of 40 and female. The NS5B sequences of 32 Kayseri genotype 4 isolates were closely related with type 4d sequences but formed a separate cluster. Conclusion:The introduction of type 4d HCV into the Kayseri region probably took place 30-75 years ago, as predicted by molecular clock analysis.
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