Human Biomolecules Research Articles

Characterization of Human Anti-Dengue NS1 Monoclonal Antibodies Derived from Patients Infected with DENV-2.

Mouse antibodies specific to dengue NS1 have been widely investigated for their cross-reactivity with several human biomolecules. This is the first study demonstrating the cross-reactivity of human monoclonal antibodies (HuMAbs) specific to dengue NS1 isolated from patients infected with dengue virus serotype-2 (DENV-2). Nine anti-NS1 HuMAbs, which were mainly derived from patients in convalescent-phase after secondary infection of DENV-2, were characterized. Their cross-reactivity with plasminogen, thrombin, and endothelial cells was investigated, following which plasmin-formation assays were performed. All anti-NS1 HuMAbs exhibited cross-reactivity with human plasminogen (Plg), but not with thrombin or endothelial cells. Moreover, all HuMAbs exhibiting cross-reactivity with Plg converted Plg to plasmin in the plasmin-formation assay. These results suggest the implications and drawbacks of using anti-NS1 antibodies in immunotherapy.

The examination of ancient DNA: guidelines on precautions, controls, and sample processing

The young discipline of palaeogenetics has developed into a successful and expectant field of archaeobiological research within the last decade. Palaeogenetic investigation (e.g. PCR, DNA sequencing) of ancient specimens is, however, susceptible to falsification by the presence of contamination from more recent times. Contamination which can lead to amplification of non-authentic sequences is known to stem from several sources: (i) human biomolecules derived from the persons performing the genetic experiments, perhaps also from the archeologists and other persons who have previously handled the specimens or (ii) edaphic DNA sequences derived primarily from bacterial or fungal growth upon the specimen. A third source of contamination can arise from (iii) substances used for conservation of specimens. Here we give advice on the correct processing of prehistoric bone samples when further molecular biological examination is required. Along with the demonstration of necessary precautions and working conditions, we further explain how an unequivocal DNA contamination monitoring is performed.

Molecular engineering: applications to the clinical laboratory

Advances in cellular and molecular biology methods have led to the molecular engineering of novel human biomolecules, some of which have been successfully applied to the documentation of clinical laboratory assays. Here I describe the use of engineered chimeric antibodies in the clinical immunology laboratory in three principal applications: (a) as reference proteins to document the specificity of clinical assay reagents, be used as reagent-grade purified antigens, and facilitate the epitope mapping of antibody reagents; (b) as calibration proteins to assign mass/volume estimates to proposed antibody standards; and (c) as interference proteins to study the effects of naturally occurring autoantibodies on the accuracy and sensitivity of current clinical assays. The model recombinant proteins used for these illustrations are chimeric antibodies with a defined V-region specificity for one of two haptens (nitrophenyl or dansyl) and C-region domains covering a spectrum of human isotypes. I also describe a panel of mutant human IgG1-4 anti-dansyl chimeric antibodies that have been genetically engineered with swapped, deleted, or point-mutated wild-type C-region exons and used as specialized reagents for mapping the epitopes to which clinically used human IgG-specific monoclonal antibodies bind. Finally, the use of a recombinant human IgG1 anti-human IgE Fc chimeric antibody to simulate human IgG anti-IgE autoantibody interference in assays of total serum IgE is investigated.