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. Author manuscript; available in PMC: 2010 Oct 17.
Published in final edited form as: J Infect Dis. 2008 Jun 15;197(12):1634–1642. doi: 10.1086/588385

Table 4.

Ex Vivo and Cultured IFN-γ ELISPOT Assay Responses for CMV-Seronegative Subjects

Ex vivo ELISPOT Assay
Results (SFU/106 PBMC)a 		Cultured IFN-γ ELISPOT Assay Results
(SFU/106 cultured cells)b
pp65 gB IE1 pp65 gB IE1
Group 1 Wk 32 Wk 0 Wk 32 Wk 0 Wk 32 Wk 0 Wk 32
V01OC002 0 0 0 100 242 6 1475 75 14
V01OC005 8 10 12 0 42 50 83 42 25
V01OC008c 3 3 8 36 792 0 92 17 183
V01OC009 3 1 8 0 6 50 6 250 192
V01OC013 18 29 1 125 2258 92 125 0 42
V01OC014 29 31 4 11 1967 50 4467 0 0
V01OC016 32 22 8 11 2417 47 783 14 100
V01ST001 12 23 17 6 358 217 608 75 89
Group 2 Wk 32 Wk 0 Wk 32 Wk 0 Wk 32 Wk 0 Wk 32
V01ST002 0 3 0 11 0 8 33 0 0
V01ST004 52 25 15 75 5017 56 775 14 58
V01CO001 3 9 7 17 39 53 117 36 0
V01FH001 70 40 2 33 2433 6 542 50 17
V01OC021d 90 92 25 100 6067 217 5575 111 150
V01ST005 0 3 6 0 0 8 14 17 17
V01FH004 96 33 27 61 417 8 6375 19 33
V01OC022 27 53 0 3 4517 383 1600 42 50
Group 3 Wk 16e Wk 0 Wk 16 Wk 0 Wk 16 Wk 0 Wk 16
V01OC023 14 n.d.f 0 33 58 333 538 8 11
V01OC026 56 n.d. 0 28 1900 542 1658 19 17
V01OC029 78 n.d. 0 53 1267 0 792 67 50
V01FH005 5 n.d. 5 17 1542 58 2100 25 108
V01OC030 8 n.d. 5 8 0 0 3 0 6
V01ST006 8 n.d. 0 11 583 17 950 33 92
a

A subject was considered to be a responder to the cytomegalovirus (CMV) proteins phosphoprotein 65 (pp65), glycoprotein B (gB) or immediate early antigen 1 (IE1) by ex vivo gamma interferon (IFN-γ) ELISPOT assay if the mean spot forming units per 106 peripheral blood mononuclear cells (SFU/106 PBMC) for replicate wells was greater than or equal to 50 and the mean SFU/well for replicate wells was greater than twice the mean background (without peptide) SFU/well. Positive responses are in bold type. Using the established cut-off, 63 CMV-seronegative subjects were all negative in the assay (100% specificity) and 50 CMV-seropositive subjects were all positive for at least one of the three antigens in the assay (100% sensitivity); positive responses for the CMV-seropositive subjects ranged from 50 SFU/106 PBMC to the upper limit of the assay, 6000 SFU/106 PBMC (authors’ unpublished data).

b

A subject was considered to be a responder to pp65, gB or IE1 by the cultured ELISPOT assay if the SFU/106 cultured cells were >250 and the SFU/well was >2X the SFU of wells without peptide. Data from the analysis of PBMC from CMV-seronegative subjects prior to administration of the CMV DNA vaccine suggested that some subjects may have low levels of crossreactive T-cell responses to peptides in the pools [data not shown]; therefore, the criteria for a positive response to the vaccine included the requirement that the SFU/106 cultured cells was >2X SFU/106 cultured cells at baseline. Positive responses are in bold type. Using these criteria, no positive responses were detected for PBMC stimulated with the IE1 specificity control peptides (IE1 is not encoded in the vaccine, n=22 CMV-seronegative subjects vaccinated with VCL-CB01, 100% specificity for vaccine response). The lack of IE1 responses in PBMC from CMV-seronegative subjects up to Week 32 of the study suggests that none of those subjects acquired CMV during the course of the trial.

c

Wk 0 PBMC were not available, Wk 2 PBMC were used in the assay

d

Wk 32 PBMC were not available, Wk 24 PBMC were used in the assay

e

Results from initial evaluation in the ex vivo ELISPOT assay in which pp65 peptides are split into two pools each are reported. The data reported are the sums of SFU/106 PBMC for pool I and pool II

f

n.d.,Not done