Structural polymorphism of glycophorins demonstrated by immunoblotting techniques

We have explored the polymorphism of the glycophorin system in the human erythrocyte membrane using the immunoblotting techniques and examining 52 individuals selected without prior bias as to their serologic state and ten documented serologic variants of M, N, S, s blood group system. Polyclonal antisera to alpha glycophorin and to alpha glycophorin CNBr carboxyl terminal fragment C (residues 82-131) and M and N specific monoclonal antibodies (MoAbs) were used. The first two reagents detect specific regions of the alpha glycophorin molecule and all electrophoretically resolved species of glycophorins immunologically related to alpha and delta glycophorins (delta glycophorin, [alpha-delta] hybrids and other glycophorins with an alteration in the carboxyl terminal segment); the M and N MoAbs identified the glycophorin species containing or lacking the M or N determinant in the amino terminal octapeptide structures. We find that immunoblotting confirmed in all cases the serologically determined phenotype; we also find that polymorphic forms of the glycophorin system are relatively infrequent; immunoblotting, independent from serologic testing, was capable of detecting five mutants, two most likely S-s-U-phenotypes; a new glycophorin species was detected in normal red cells with both antiglycophorin and antipeptide C sera, which is not evident with MoAbs; immunoblots of known glycophorin variants (En(a-), U-, Mg, Mi I, II, III, V, and Sta) confirmed but also extended our knowledge of the abnormal glycophorins involved; and the He+ and Wrb(-) cells showed normal patterns.     

Comparative analysis of hepatitis C virus core protein in the plasma and serum samples from HCV-infected blood donors and patients with hepatitis C

The aim of the study was to develop a sensitive and specific method for revealing the direct marker of hepatitis C virus (HCV)--core protein in the serum and to test it in the laboratory setting. Experiments were made on plasma and serum samples from asymptomatic HCV-seropositive blood donors (n=65), patients with acute (AHC) and chronic (CHC) hepatitis C (n=295), and HCV-seronegative blood donors (n=20). The processing protocol for serum included their concentration by means of polyethylene glycol and subsequent treatments of pellets to detect core protein in free virions, nonenveloped nucleocapsids, and immune complexes. This allowed an assay to be developed for the detection of core protein, by using a sandwich ELISA. Inclusion of a combination of three original monoclonal antibodies into the sandwich could reveal in the samples core proteins of at least 3 genotypes of HCV (1, 2, and 3) with a sensitivity of 20 pg/ml in the majority of HCV-infected subjects. The results of determination of core protein and HCV RNA correlated with a high degree of sensitivity. To detect HCV in the blood of patients with AHC, it was shown to be sufficient to find freely circulating virions whereas an analysis of immune complexes should be included in cases of CHC to achieve more sensitivity. The findings are a basis for developing a test system for the diagnosis of hepatitis C, including its early stages before seroconversion and for determining a viral load during interferon therapy. Introduction of the method into practice increases the reliability of the diagnosis of hepatitis C and virus-free safety of blood transfusions.     

An anti-EnaTS detected in the serum of an MiI homozygote

The serum of EH reacted with all red cells (RBCs) except her own, ficin- or trypsin-treated red cells, and En(a-) red cells. This reactivity defined an anti-EnaTS specificity. The red cells of the proposita typed as M-N+S-S+, Vw+Mur-Hil-Hut-Anek-Lane-, Wr(a-b+), EnaKT+. Red cells of five relatives were Vw+ and positive with her serum. Titration studies suggest that EH is genetically an MiI homozygote and that her Vw+ relatives are MiI heterozygotes. There is no history of consanguinity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting studies have agreed with the serologic observations. A variant sialoglycoprotein of faster mobility than normal glycoprotein A, but no normal glycoprotein A, was detected on her red cells. Treatment with N-glycanase did not alter the mobility, which indicated that there was no N-glycosylation of residue 26. These findings are in agreement with the reported properties of the Mi.I-specific glycoprotein A. The relatives' Vw+ red cells showed the variant sialoglycoprotein and normal glycoprotein A. EH appears to be the first reported MiI homozygote.     

The role of hepatitis C virus RNA detection in various substrates of patients with chronic hepatitis C

Puncture biopsy of the liver and blood count were made in 72 patients with chronic hepatitis C (CHC). Morphological alterations in the liver were assessed by Knodell index. The blood serum, lymphocytes and hepatic tissue were examined for a genome form of hepatitis C virus (HCV) RNA, blood lymphocytes and hepatic tissue--for a relevant replication form. HCV RNA was detected using "nested" RT-PCR. Only 26% patients had symptoms of asthenovegetative and dyspeptic syndromes. Normal alaninaminotransferase (ALT) level was observed in 24% patients, the rest had it high. HCV RNA was encounted more frequently in hepatic tissue than lymphocytes or serum (83, 68 and 46%, respectively). A replication form of HCV RNA was present in hepatic tissue of 31% patients and was absent in the lymphocytes. The incidence of the RNA detection was not related either to the disease symptoms or morphological alterations in hepatic tissue. The occurrence of the genome and replication forms in hepatic tissue does not correlate to ALT level. HCV RNA occurs more often in the serum, blood lymphocytes and in three substrates simultaneously in patients with hyperalatemia.     

Antibody-binding epitope differences in the nucleoprotein of avian and mammalian influenza A viruses

Abstract Influenza virus nucleoprotein (NP) binds to the viral genome RNA and forms the internal ribonucleoprotein complex of the virus particle. Avian and human influenza virus NP have characteristic differences at several amino acid positions. It is not known whether any of these differences can be recognized by antibodies. In the present study five monoclonal antibodies (MAbs) were produced against NP of A/Duck/Novosibirsk/56/05 (H5N1) influenza virus. Two MAbs discerned human and avian influenza strains on ELISA testing. The NP expressed in a prokaryotic system was used for the analysis of site-specific mutants carrying amino acid substitutions in the relevant positions. Amino acid residues in positions 100 and 101 were shown to be recognized by the MAbs. The residue in position 100 is host-specific, and its recognition by the MAb 2E6 may be useful for the differentiation of human and avian viruses. The data are discussed in view of the effects of amino acid substitutions in influenza virus NP affecting both host range and antibody-binding specificity.     

Antibiotic resistance in bacteria - an emerging public health problem

The discovery and eventual introduction of anti-microbial agents to clinical medicine was one of the greatest medical triumphs of the twentieth century that revolutionized the treatment of bacterial diseases. However, the gradual emergence of populations of antibiotic-resistant bacteria resulting from use, misuse and outright abuse of antibiotics has today become a major public health problem of global proportions. This review paper examines the origins and molecular epidemiology of resistance genes, global picture of antibacterial resistance, factors that favour its spread, strategies for its control, problems of control and the consequences of failure to contain antibiotic resistance in bacteria.