Neutralizing antibody assessments play a central role in human immunodeficiency virus type-1 (HIV-1) vaccine development but it is unclear which assay, or combination of assays, will provide reliable ...measures of correlates of protection. To address this, an international collaboration (NeutNet) involving 18 independent participants was organized to compare different assays.
Each laboratory evaluated four neutralizing reagents (TriMab, 447-52D, 4E10, sCD4) at a given range of concentrations against a panel of 11 viruses representing a wide range of genetic subtypes and phenotypes. A total of 16 different assays were compared. The assays utilized either uncloned virus produced in peripheral blood mononuclear cells (PBMCs) (virus infectivity assays, VI assays), or their Env-pseudotyped (gp160) derivatives produced in 293T cells (PSV assays) from molecular clones or uncloned virus. Target cells included PBMC and genetically-engineered cell lines in either a single- or multiple-cycle infection format. Infection was quantified by using a range of assay read-outs that included extracellular or intracellular p24 antigen detection, RNA quantification and luciferase and beta-galactosidase reporter gene expression.
PSV assays were generally more sensitive than VI assays, but there were important differences according to the virus and inhibitor used. For example, for TriMab, the mean IC50 was always lower in PSV than in VI assays. However, with 4E10 or sCD4 some viruses were neutralized with a lower IC50 in VI assays than in the PSV assays. Inter-laboratory concordance was slightly better for PSV than for VI assays with some viruses, but for other viruses agreement between laboratories was limited and depended on both the virus and the neutralizing reagent.
The NeutNet project demonstrated clear differences in assay sensitivity that were dependent on both the neutralizing reagent and the virus. No single assay was capable of detecting the entire spectrum of neutralizing activities. Since it is not known which in vitro assay correlates with in vivo protection, a range of neutralization assays is recommended for vaccine evaluation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Receptor tyrosine kinases (RTK) are proteins that undergo dimerization and/or multimerization and autophosphorylation in response to ligand stimulation. Members of the RTK family are receptors for a ...series of growth factors that, upon stimulation, are able to start signaling events that promote cell growth and differentiation. A class of RTKs, the Eph receptors (EphRs), are found in a variety of cell types and play important roles in patterning the central and peripheral nervous systems, as well as in synapse and neural crest formation. Interaction of Eph receptors with their ephrin ligands activates signal transduction pathways that lead to cytoskeletal remodeling through formation of many stable or transient protein-protein interactions. However, these intracellular signal transduction pathways that lead to cytoskeletal remodeling are not well understood. Here, we combined Blue Native PAGE (BN-PAGE) and mass spectrometry (MS) to analyze protein-protein interactions as a result of ephrin stimulation. We analyzed both lysates and phosphotyrosine immunoprecipitate (pY99-IP) of unstimulated and ephrin-stimulated cells. Our experiments allowed us to characterize many constitutive homo- and hetero-protein complexes from the cell lysate. Furthermore, BN-PAGE and MS of the pY99-IPs from both unstimulated and stimulated cells allowed us to analyze protein-protein interactions that resulted upon ephrin stimulation. Combination of BN-PAGE and MS also has the potential for the analysis of stable and transient protein-protein interactions in other ligand-stimulated RTK-dependent signal transduction pathways.
Neutralizing antibodies provide markers for vaccine-induced protective immunity in many viral infections. By analogy, HIV-1 neutralizing antibodies induced by immunization may well predict vaccine ...effectiveness. Assessment of neutralizing antibodies is therefore of primary importance, but is hampered by the fact that we do not know which assay(s) can provide measures of protective immunity. An international collaboration (NeutNet) involving 18 different laboratories previously compared different assays using monoclonal antibodies (mAbs) and soluble CD4 (Phase I study).
In the present study (Phase II), polyclonal reagents were evaluated by 13 laboratories. Each laboratory evaluated nine plasmas against an 8 virus panel representing different genetic subtypes and phenotypes. TriMab, a mixture of three mAbs, was used as a positive control allowing comparison of the results with Phase I in a total of nine different assays. The assays used either uncloned virus produced in peripheral blood mononuclear cells (PBMCs) (Virus Infectivity Assays, VIA), or Env (gp160)-pseudotyped viruses (pseudoviruses, PSV) produced in HEK293T cells from molecular clones or from uncloned virus. Target cells included PBMC and genetically engineered cell lines in either single- or multiple-cycle infection format. Infection was quantified by using a range of assay read-outs including extra- or intra-cellular p24 antigen detection, luciferase, beta-galactosidase or green fluorescent protein (GFP) reporter gene expression.
Using TriMab, results of Phase I and Phase II were generally in agreement for six of the eight viruses tested and confirmed that the PSV assay is more sensitive than PBMC (p = 0.014). Comparisons with the polyclonal reagents showed that sensitivities were dependent on both virus and plasma.
Here we further demonstrate clear differences in assay sensitivities that were dependent on both the neutralizing reagent and the virus. Consistent with the Phase I study, we recommend parallel use of PSV and VIA for vaccine evaluation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract In AIDS vaccine development the pendulum has swung towards a renewed emphasis on the potential role for neutralizing antibodies in a successful global vaccine. It is recognized that ...vaccine-induced antibody performance, as assessed in the available neutralization assays, may well serve as a “gatekeeper” for HIV-1 subunit vaccine prioritization and advancement. As a result, development of a standardized platform for reproducible measurement of neutralizing antibodies has received considerable attention. Here we review current advancements in our knowledge of the performance of different types of antibodies in a traditional primary cell neutralization assay and the newer, more standardized TZM-bl reporter cell line assay. In light of recently revealed differences (see accompanying article) in the results obtained in these two neutralization formats, parallel evaluation with both platforms should be contemplated as an interim solution until a better understanding of immune correlates of protection is achieved.
In the course of our research, we surveyed the educational programmes of the football academies of Hungary. We wished to reveal the educational aspects of the life of the students at the football ...academies. The purpose of our project is to comparatively analyse the formal and conceptual dimensions of the educational programmes of the academies through an analysis of the documents of the academies concerned. We also conducted semi-structured interviews with the heads of the social- and educational sections of the academies (N=6). We used the results of the interviews to check–confirm or refute–the results we found. We believe that the findings of our research make it possible for us to better understand the elements and value-based components of the educational dimensions of the football academies. In this way, our survey is similar to the projects of researchers who worked with local educational programmes (for example, Brezsnyánszky et al., 2000). As a conclusion of our research, we may point out that both the formal and conceptual dimensions of the educational programmes of the individual football academies are strongly heterogeneous, and the quality of their pedagogical programmes is often questionable. The results yielded by the analysis of the interviews suggest that although an educational-social department is present at each of the academies, some our former conclusions in connection with the general standards of the educational work were confirmed by the answers we received from our respondents. The academies, almost without an exception, produce their own educational programmes and carry out their educational work individually, and do not cooperate with the other institutions. There is, consequently, no uniform and standard educational work, and there is no professional documentation of the work going on either. In this way, the quality of educational work is not really able to improve.
Among the major circulating HIV-1 subtypes, subtype C is the most prevalent. To generate full-length subtype C clones and sequences, we selected 13 primary (PBMC-derived) isolates from Zambia, India, ...Tanzania, South Africa, Brazil, and China, which were identified as subtype C by partial sequence analysis. Near full-length viral genomes were amplified by using a long PCR technique, sequenced in their entirety, and phylogenetically analyzed. Amino acid sequence analysis revealed 10.2, 6.3, and 17.3% diversity in predicted Gag, Pol, and Env protein sequences. Ten of 13 viruses were nonmosaic subtype C genomes, while all three isolates from China represented B/C recombinants. One of them was composed primarily of subtype C sequences with three small subtype B portions in gag, pol, and nef genes. Two others exhibited these same mosaic regions, but contained two additional subtype B portions at the gag/pol overlap and in the accessory gene region, suggesting ongoing B/C recombination in China. All subtype C genomes contained a prematurely truncated second exon of rev, but other previously proposed subtype C signatures, including three potential NF-kappa B-binding sites in the viral promoter-enhancer regions, were found in only a subset of these genomes.
The Hungarian football academies, since they were established, have been closely bound to politics, to the person of the Prime Minister. In the first part of our study we intend to provide an insight ...into the research question and present some international examples to the reader, focusing especially on various research findings. The next chapter is devoted to the sports schools as special institutions. The closing chapter of our study deals with the three academies we included in our research and for which we had conducted a survey on location, the results of which were summed up in a previous paper. Our main aim in research was to get a general picture of the functioning and legal embedding of the Hungarian football academies. We used several methods in our research, such as document analysis and interview analysis methods. We have come to the conclusion that the football academies we have studied have different infrastructural backgrounds, coaches and employed academics.
The consultation was jointly organized by the WHO-UNAIDS HIV Vaccine Initiative and the Quality Assurance and Safety of Biologicals Team of the World Health Organization (WHO). Thirty-four experts ...from 16 developed and developing countries attended the meeting, bringing together expertise from academic institutions, clinical trial centres, national and international regulatory authorities. Representatives of major pharmaceutical companies were also invited. The primary objective of the meeting was to identify gaps that need to be addressed from regulatory perspective to ensure appropriate progress of HIV vaccine development from basic research to human trials, licensing and future application, with a special focus on needs of developing countries. As a result of discussions, the following priority needs were identified and recommendations were made in order to establish an appropriate regulatory framework for the development and evaluation of preventive HIV/AIDS vaccines, which were divided in two main areas: (a) standardization and control of candidate HIV/AIDS vaccines, and (b) approaches to the conduct of clinical trials of candidate HIV/AIDS vaccines.
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