Geographical distribution of hepatitis C virus genotypes in blood donors:an international collaborative survey

The frequency of infection with the six classified major genotypes of hepatitis C virus (HCV) was investigated in 447 infected volunteer blood donors from the following nine countries: Scotland, Finland, The Netherlands, Hungary, Australia, Egypt, Japan, Hong Kong, and Taiwan. Viral sequences in plasma from blood donors infected with HCV were amplified in the 5'-noncoding region and were typed by restriction fragment length polymorphism analysis. Electrophoresis of DNA fragments produced by cleavage with HaeIII-RsaI and ScrFI-HinfI allowed HCV types 1 (or 5), 2, 3, 4, and 6 to be identified. Further analysis with MvaI-HinfI allowed sequences of the type 5 genotype to be distinguished from sequences of type 1 genotype. Types 1, 2, and 3 accounted for almost all infections in donors from Scotland, Finland, The Netherlands, and Australia. Types 2 and 3 were not found in the eastern European country (Hungary), where all but one of the donors were infected with type 1. Donors from Japan and Taiwan were infected only with type 1 or 2, while types 1, 2, and 6 were found in those from Hong Kong. HCV infection among Egyptians was almost always by type 4. Donors infected with HCV type 1 showed broad serological reactivity with all four antigens of the second generation Chiron RIBA-2 assay (Chiron Corporation, Emeryville, Calif.), while infection with divergent HCV genotypes elicited antibodies mainly reactive to c22-3 and c33c. Reactivities with antibodies 5-1-1 and c100-3 were infrequent and were generally weak, irrespective of the geographical origin of the donor. Because the envelope region of HCV is even more variable than the NS-4 region, it is likely that vaccines based on these proteins need to be multivalent and perhaps specifically adapted for different geographical regions.link_to_subscribed_fulltex

Fc receptors of rat peritoneal macrophages: immunoglobulin class specificity and sensitivity to drugs affecting the microfilament or microtubule system.

Macrophage-cytophilic antibody activity of various immunoglobulin classes and subclasses was tested in two different rosetting systems. Cytophilic antibody activity of IgM, IgG2a and IgG1 was verified in the SRBC system, while IgM, IgG2a and IgG2c were found to be active in the trypanosome system. Sensitivity to cytochalasin B treatment of SRBC rosette formation was dependent on the class of antibody and decreased in the following order: IgM > IgG1 > IgG2a. Trypanosome rosette formation was prevented by the same drug regardless the type of antibody. Vinblastin caused an enhancement of rosette formation in the SRBC system in low concentration, except when the antibody belonged to subclass IgG1. The enhancing effect was less pronounced in the trypanosome system