Browsing by Author "Tarragona-Fiol, Tony"

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    Equivalence of ELISpot Assays Demonstrated between Major HIV Network Laboratories
    (PLOS ONE, 2010-12-14) Gill, Dilbinder K.; Huang, Yunda; Levine, Gail L.; Sambor, Anna; Carter, Donald K.; Sato, Alicia; Kopycinski, Jakub; Hayes, Peter; Hahn, Bridget; Birungi, Josephine; Tarragona-Fiol, Tony; Wan, Hong; Randles, Mark; Cooper, Andrew Raxworthy; Ssemaganda, Aloysius; Clark, Lorna; Kaleebu, Pontiano; Self, Steven G.; Koup, Richard; Wood, Blake; McElrath, M. Juliana; Cox, Josephine H.; Hural, John; Gilmour, Jill
    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-c) 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 (21.5%, 1.5%) and CEF (20.4%, 7.8%) responses, were both contained in the prespecified equivalence margin of interval [215%, 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.
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    Setting up a Standardized Peripheral Blood Mononuclear Cells Processing Laboratory to Support Multi-center HIV/AIDS Vaccine and Intervention Trials.
    (Labmedicine, 2011) Njai, Harr Freeya; Gombe, Ben; Khamis, Tomusange; Birungi, Josephine; Ruzagira, Eugene; Admassu, Dareskedar; Tarragona-Fiol, Tony; Porter, Kholoud; Stevens, Gwynneth; Mugisha, Joseph; Gilmour, Jill; Kamali, Anatoli; Kaleebu, Pontiano
    Despite infrastructure and capacity challenges in Africa, significant development has been made in the number of laboratories supporting immunological and safety studies required for large-scale HIV/AIDS vaccine or intervention trials. In Uganda, cohorts participating in HIV intervention trials are often recruited from rural areas. To avoid transporting samples from intervention trial areas over long distances (120 km) to central laboratories in Entebbe, we set up a standardized peripheral blood mononuclear cells (PBMCs) processing laboratory at a field station in Masaka, southwest Uganda. The laboratory was well equipped and enrolled into the International AIDS Vaccine Initiative (IAVI) Quality Assurance (QA) program. Staff was trained in laboratory techniques and Good Clinical Laboratory Practice (GCLP). The laboratory received IAVI and GCLP accreditation in 2008. In this paper we describe the process and achievements of measures taken to overcome challenges, to build staff capacity, and to optimize the quality of the cells yielded.