Equivalence of ELISpot assays demonstrated between major HIV network laboratories

Background

The Comprehensive T Cell Vaccine Immune Monitoring Consortium (CTC-VIMC) was created to provide standardized immunogenicity monitoring services for HIV vaccine trials. The ex vivo interferon-gamma (IFN-γ) ELISpot is used extensively as a primary immunogenicity assay to assess T cell-based vaccine candidates in trials for infectious diseases and cancer. Two independent, GCLP-accredited central laboratories of CTC-VIMC routinely use their own standard operating procedures (SOPs) for ELISpot within two major networks of HIV vaccine trials. Studies are imperatively needed to assess the comparability of ELISpot measurements across laboratories to benefit optimal advancement of vaccine candidates.

Methods

We describe an equivalence study of the two independently qualified IFN-g ELISpot SOPs. The study design, data collection and subsequent analysis were managed by independent statisticians to avoid subjectivity. The equivalence of both response rates and positivity calls to a given stimulus was assessed based on pre-specified acceptance criteria derived from a separate pilot study.

Findings

Detection of positive responses was found to be equivalent between both laboratories. The 95% C.I. on the difference in response rates, for CMV (−1.5%, 1.5%) and CEF (−0.4%, 7.8%) responses, were both contained in the pre-specified equivalence margin of interval [−15%, 15%]. The lower bound of the 95% C.I. on the proportion of concordant positivity calls for CMV (97.2%) and CEF (89.5%) were both greater than the pre-specified margin of 70%. A third CTC-VIMC central laboratory already using one of the two SOPs also showed comparability when tested in a smaller sub-study.

Interpretation

The described study procedure provides a prototypical example for the comparison of bioanalytical methods in HIV vaccine and other disease fields. This study also provides valuable and unprecedented information for future vaccine candidate evaluations on the comparison and pooling of ELISpot results generated by the CTC-VIMC central core laboratories.     

Looking for sex in the fungal pathogens Cryptococcus neoformans and Cryptococcus gattii

Why are we interested in understanding the mode of reproduction being used by the fungal pathogens Cryptococcus neoformans and Cryptococcus gattii? Empirical evidence has finally supported the long-held assumption that, by increasing the rate of adaptive evolution, sex increases the chances of long-term survival. Understanding the ability of pathogenic organisms to adapt to diagnostic and treatment regimes is also important in the fight against the diseases caused by these organisms. This review looks at the different approaches used to identify population structure in C. neoformans and C. gattii. These are sexual species; however, recombination in natural populations has only recently been found. We highlight the importance of population selection and the value of both indirect molecular analysis and direct biological evidence for sexual recombination, when looking for the mode of reproduction in these fungal pathogens.     

Cell cycle related proteins in hyperplasia of usual type in breast specimens of patients with and without breast cancer

Background  

Hyperplasia of usual type (HUT) is a common proliferative lesion associated with a slight elevated risk for subsequent development of breast cancer. Cell cycle-related proteins would be helpful to determine the putative role of these markers in the process of mammary carcinogenesis. The aim of this study was to analyze the expression of cell cycle related proteins in HUT of breast specimens of patients with and without breast cancer, and compare this expression with areas of invasive carcinomas.     

JLIN: A java based linkage disequilibrium plotter

Background  

A great deal of effort and expense are being expended internationally in attempts to detect genetic polymorphisms contributing to susceptibility to complex human disease. Techniques such as Linkage Disequilibrium mapping are being increasingly used to examine and compare markers across increasingly large datasets. Visualisation techniques are becoming essential to analyse the ever-growing volume of data and results available with any given analysis.     

Translation of an experimental oral vaccine formulation into a commercial product

An effective experimental vaccine may fail to become a therapeutic reality for a number of scientific, regulatory or commercial reasons. In this review, we share some of our personal experiences as University-based researchers and provide an account of some of the problems that we have encountered during preliminary scale-up and assessment of an oral influenza vaccine formulation. Many of the problems we have faced have been non-scientific and related to identifying project-funding sources, finding suitable contract manufacturing companies that are GMP compliant, and protecting intellectual property generated from the scientific studies. The review is intended as a practical guide that will allow other researchers to adopt effective strategies to permit the translation of an effective experimental formulation to a viable commercial product.     

Oral delivery of tetanus toxoid using vesicles containing bile salts (bilosomes) induces significant systemic and mucosal immunity

Protein antigens administered via the oral route are exposed to a hostile environment in the gastrointestinal tract, consisting of digestive enzymes and a range of pH (1-7.5). Using a delivery system can afford protection to entrapped components against degradation and permit delivery of antigen to the cells responsible for generating local and systemic immune responses. In this comparative study, mice were immunised orally with tetanus toxoid (40 or 200 microg dose/mouse, four doses in total) entrapped in non-ionic surfactant vesicles formulated with bile salts (bilosomes). The higher entrapped dose (BV-TT, 200 microg) induced IgG1 by study week 3 to similar levels to those observed with subcutaneous un-entrapped TT at the lower (<50 microg) dose. However, both bilosome formulations (BV-TT, low, and high doses), though not un-entrapped TT, caused a rise in the numbers of IgA positive plasma cells observed in the small intestine, primarily in the first 15 cm of the small intestine.     

The importance of pelvic lymph node dissection in men with clinically localized prostate cancer

Despite advances in noninvasive staging, pelvic lymph node dissection (PLND) remains the most accurate means of detecting lymph node metastases in men with clinically localized prostate cancer. Nomograms exist that can identify patients at low risk for lymphatic metastases according to preoperative information. In general, it seems reasonable to omit PLND in men with a biopsy Gleason sum of 6 or less and a prostate-specific antigen level of 10 ng/mL or less. Ultimately, however, this decision should be made according to physician and patient preference, considering the low contemporary morbidity associated with PLND. When PLND is performed, studies suggest that an extended dissection maximizes the detection rate of nodal involvement. Retrospective data indicate that an extended dissection might play a therapeutic role in a subset of patients with a limited lymph node burden. However, this might be an artifact of stage migration, and prospective studies are needed to evaluate this further.