TABLE 2.

Prevaccination statistics and positive response definition for each assay performed in the trial

Assay antigen stimulantUnitAssay statisticsDefinition of a positive response
Prevaccination or placebo responseHighest prevaccination levelaHighest placebo levelaPositive responseaReplicate variationRequirements for controls
nMeanaMediana99%
Ex vivo IFN-γ ELISPOT for pool 90, pools 1 to 4, and pool 9SFC/106 cells2520.490.008.7510.05.01 pool = 38b; 2 pools = 30bCVc < 70%Mock < 55, >4× mock
IL-7-IL-15 ex vivo IFN-γ ELISPOT and for pool 90, pools 1 to 4, and pool 9SFC/106 cells2203.790.0092.581.3163.81 pool > 163; 2 pools > 93CV < 70%>4× mock
Cultured IFN-γ ELISPOT performed on pool 9 STCLSFC/106 cells54−6.0−6.368.85669
Cultured IFN-γ ELISPOT performed on pool 90 STCLSFC/106 cells2813112.5263269269
Cultured IFN-γ ELISPOT for total of pools 90 and 9SFC/106 cells335256.32632692691 pool = 300dCV < 70%Mock < 250, >4× mock, phytohemagglutinin > 1,000
[3H]thymidine proliferation for pools 90 and 9SI2330.940.863.183.583.055SEB > 20
CFSE proliferation for pools 90 and 9PI161−0.0020.0000.0150.0150.0100.03SEB > 0.5, >4× mock
WB IFN-γ ICS for pool 90, pools 1 to 4, and pool 9% CD3/CD4 CD69/IFN-γ+2920.0010.0000.0250.0220.0541 pool = 0.055Mock < 0.03,e >4× mock
  • a Data are for mock (background)-subtracted response of cells stimulated with peptide antigens for pool 90, pools 1 to 4, and pool 9.

  • b This cutoff is based on IAVI CORE laboratory data from trial 006 (n = 1,216 assays, highest prevaccinnation or placebo response, 38 SFC/106 cells).

  • c CV, coefficient of variation.

  • d Due to detection of an HIVA-specific response to pool 10 detectable in prevaccination samples and healthy laboratory workers, a positive response in this assay required >300 SFC/106 in wells stimulated with pool 9 or a similar response to pool 90 together with at least one from pool 1, 3, or 4 or peptide 42. Assays with positive responses to pool 90 and pool 10 (pool 10 is identical to pool 2 but lacks peptide 42) only were excluded from analysis.

  • e Minimum of events in the CD3+ CD4+ gate required was dependent on the following background levels: 0.00 to 16,000 events, 0.01 to 20,000 events, 0.02 to 30,000 events, and 0.03 to 35,000 events.