Spontaneous mutation rate of measles virus: direct estimation based on mutations conferring monoclonal antibody resistance.

Mutations Conferring Monoclonal Antibody Virus: Direct Estimation Based on Spontaneous Mutation Rate of Measles

Identification of Drug Resistant Mutants of HBV (Hepatitis B Virus) by Direct Sequencing in Iranian Patients Treated with Lamivudine

Background and Aims: lamivudine is amongst the antiviral for drug chronic hepatitis B treatment. During therapy with lamivudine, variants may emerge with YMDD mutation in the reverse transcriptase (RT) region of polymerase gene. This mutation might have a role in drug resistant for HBV. Materials and Methods: HBV DNA extraction from serum sample of 88 patients, were subjected to nested PCR for ...

Detection of A2142C, A2142G, and A2143G Mutations in 23s rRNA Gene Conferring Resistance to Clarithromycin among Helicobacter pylori Isolates in Kerman, Iran

Background: Clarithromycin resistance in Helicbacter pylori has been found to be associated with point mutations in 23s rRNA gene leads to reduced affinity of the antibiotic to its ribosomal target or changing the site of methylation. The aim of this study was to determine the most important point mutations in 23s rRNA gene in H. pylori that are closely related to clarith-romycin resistance amo...

Construction and Expression of Hepatitis B Surface Antigen Escape Variants within the "a" Determinant by Site Directed Mutagenesis

Background: The antibody response to hepatitis B surface antigen (HBsAg) controls hepatitis B virus infection. The "a" determinant of HBsAg is the most important target for protective antibody response, diagnosis and immunoprophylaxis. Mutations in this area may induce immune escape mutants and affect the performance of HBsAg assays. Objectives: To construct clinically relevant recombinant muta...

Determination of spontaneous mutation frequencies in measles virus under nonselective conditions.

There is a paradox between the remarkable genetic stability of measles virus (MV) in the field and the high mutation rates implied by the frequency of the appearance of monoclonal antibody escape mutants generated when the virus is pressured to revert in vitro (S. J. Schrag, P. A. Rota, and W. J. Bellini, J. Virol. 73:51-54, 1999). We established a highly sensitive assay to determine frequencie...