Leukopak PBMC sample processing for preparing quality control material to support proficiency testing programs.

External proficiency testing programs designed to evaluate the performance of end-point laboratories involved in vaccine and therapeutic clinical trials form an important part of clinical trial quality assurance. Good clinical laboratory practice (GCLP) guidelines recommend both assay validation and proficiency testing for assays being used in clinical trials, and such testing is facilitated by the availability of large numbers of well-characterized test samples. These samples can be distributed to laboratories participating in these programs and allow monitoring of laboratory performance over time and among participating sites when results are obtained with samples derived from a large master set. The leukapheresis procedure provides an ideal way to collect samples from participants that can meet the required number of cells to support these activities. The collection and processing of leukapheresis samples require tight coordination between the clinical and laboratory teams to collect, process, and cryopreserve large number of samples within the established ideal time of ≤8 hours. Here, we describe our experience with a leukapheresis cryopreseration program that has been able to preserve the functionality of cellular subsets and that provides the sample numbers necessary to run an external proficiency testing program.

Establishment and maintenance of a PBMC repository for functional cellular studies in support of clinical vaccine trials.

A large repository of cryopreserved peripheral blood mononuclear cells (PBMCs) samples was created to provide laboratories testing the specimens from human immunodeficiency virus-1 (HIV-1) vaccine clinical trials the material for assay development, optimization, and validation. One hundred thirty-one PBMC samples were collected using leukapheresis procedure between 2007 and 2013 by the Comprehensive T cell Vaccine Immune Monitoring Consortium core repository. The donors included 83 human immunodeficiency virus-1 (HIV-1) seronegative and 32 HIV-1 seropositive subjects. The samples were extensively characterized for the ability of T cell subsets to respond to recall viral antigens including cytomegalovirus, Epstein-Barr virus, influenza virus, and HIV-1 using Interferon-gamma (IFN-γ) enzyme linked immunospot (ELISpot) and IFN-γ/interleukin 2 (IL-2) intracellular cytokine staining (ICS) assays. A subset of samples was evaluated over time to determine the integrity of the cryopreserved samples in relation to recovery, viability, and functionality. The principal results of our study demonstrate that viable and functional cells were consistently recovered from the cryopreserved samples. Therefore, we determined that this repository of large size cryopreserved cellular samples constitutes a unique resource for laboratories that are involved in optimization and validation of assays to evaluate T, B, and NK cellular functions in the context of clinical trials.

Development of a contemporary globally diverse HIV viral panel by the EQAPOL program.

The significant diversity among HIV-1 variants poses serious challenges for vaccine development and for developing sensitive assays for screening, surveillance, diagnosis, and clinical management. Recognizing a need to develop a panel of HIV representing the current genetic and geographic diversity NIH/NIAID contracted the External Quality Assurance Program Oversight Laboratory (EQAPOL) to isolate, characterize and establish panels of HIV-1 strains representing global diverse subtypes and circulating recombinant forms (CRFs), and to make them available to the research community. HIV-positive plasma specimens and previously established isolates were collected through a variety of collaborations with a preference for samples from acutely/recently infected persons. Source specimens were cultured to high-titer/high-volume using well-characterized cryopreserved PBMCs from National y donors. Panel samples were stored as neat culture supernatant or diluted into defibrinated plasma. Characterization for the final expanded virus stocks included viral load, p24 antigen, infectivity (TCID), sterility, coreceptor usage, and near full-length genome sequencing. Viruses are made available to approved, interested laboratories using an online ordering application. The current EQAPOL Viral Diversity panel includes 100 viral specimens representing 6 subtypes (A, B, C, D, F, and G), 2 sub-subtypes (F1 and F2), 7 CRFs (01, 02, 04, 14, 22, 24, and 47), 19 URFs and 3 group O viruses from 22 countries. The EQAPOL Viral Diversity panel is an invaluable collection of well-characterized reagents that are available to the scientific community, including researchers, epidemiologists, and commercial manufacturers of diagnostics and pharmaceuticals to support HIV research, as well as diagnostic and vaccine development.