Represent the interquartile range, the line inside each box represents the median of the samples and the whiskers represent the range of the data. Statistical significance was tested using Wilcoxon non-parametric test. (b) A comparison of eight Tat-antibody reactive types in the six response profiles and percent inhibition of transactivation. The percent inhibition at 48 h was plotted on the y-axis with samples classified by Tat antibody response profile on the x-axis. Statistical significance was tested using Nemenyi non-parametric test. * p , 0.05 comparing HIV+Tat- and HIV- groups. #p , 0.05 comparing HIV- group. doi:10.1371/journal.pone.0060825.gTat Antibody Responses to HIV-1 InfectionTable 1. Percent inhibition of Tat-transactivation after SPDP Crosslinker 3687-18-1 site depleting anti-Tat antibodies and IgG fractions of the plasma.inhibition ( )a 74.01 76.83 80.95 70.36 82.45 78.60 74.54 72.19 70.28 68.27 inhibition ( )b 27.59 30.87 13.68 38.43 22.74 17.25 26.36 19.14 11.31 16.95 inhibition ( )c 43.85 39.63 20.54 47.42 36.72 15.37 37.31 38.95 17.29 13.profiles of response Full potential responseNo. 1 2Tat 3.216 1.166 0.774 1.861 0.681 0.476 1.561 1.706 0.264 0.Combined response (N preferred reaction)4 5 6 7N-specific response17monoclonal Tat antibody2.75.12.11.HIV+Tat-1 2 3 4 5 6 7 8 90.065 0.06 0.051 0.053 0.058 0.053 0.054 
0.067 0.063 0.22.55 18.18 9.41 26.37 17.66 7.33 15.79 23.28 13.75 12.20.12 15.20 8.57 19.26 15.33 10.02 11.78 12.12 14.00 10.18.70 19.12 7.31 22.12 13.15 9.87 9.96 17.83 12.26 12.HIV-1 2 3 4 5 6 7 8 90.087 0.076 0.058 0.071 0.072 0.071 0.083 0.064 0.087 0.11.47 18.59 23.43 8.39 19.34 3.23 15.55 24.93 16.72 9.12.42 10.78 18.72 10.80 16.54 5.33 10.40 15.87 17.80 11.13.16 17.89 21.10 7.89 13.32 7.88 7.97 16.89 14.38 7.All sera were diluted 
at 1:50 for Tat-neutralization assay. The ELISA OD values and inhibition of Tat-transactivation (inhibition ( )) are shown. “No.” represents the number of each plasma sample. a inhibition of Tat-transactivation after depleting non-specific Tat antibodies with coated pPEPTIDE2 by ELISA. b inhibition of Tattransactivation after depleting Tat antibodies with coated Tat by ELISA. c inhibition of Tat-transactivation after depleting IgG fractions with coated protein G by ELISA. doi:10.1371/journal.pone.0060825.twhich reacted with 14.3, 33.3 and 59.5 of the Tat-seropositive samples, respectively (Fig. 2b, 3a). Moreover, all Tat(1?1) positive samples were both Tat(1?8) and Tat(1?6) positive, and all Tat(1?1) or Tat(1?6) positive samples were Tat(1?8) positive (Fig. 3a). This gradient of antigenicity was also present in the reactivity levels (Fig. 3a): all Tat(1?1) samples that exhibited either strong or moderate binding reactivity also exhibited strong or moderate binding reactivity to both Tat(1?8) and Tat(1?6), and all samples that exhibited either strong or moderate binding reactivity to Tat(1?1) or Tat(1?6) also exhibited either strong or moderate binding reactivity to Tat(1?8). 12926553 Comparing the reactivity patterns of the N antigens to each other as well as to that of fulllength Tat, Tat(1?8) and Tat(1?6) showed almost the samereactive patterns, which had a correlation coefficient value (R) of 0.941 (Fig. 3b). To our surprise, both Tat(1?8) and Tat(1?6) had highly similar reactivity patterns compared to full-length Tat, with the R values of 0.946 and 0.949, respectively. This strongly suggests that the important B-cell epitopes of full-length Tat are found in 1?8 aa. In contrast to the N antigens, the ant.Represent the interquartile range, the line inside each box represents the median of the samples and the whiskers represent the range of the data. Statistical significance was tested using Wilcoxon non-parametric test. (b) A comparison of eight Tat-antibody reactive types in the six response profiles and percent inhibition of transactivation. The percent inhibition at 48 h was plotted on the y-axis with samples classified by Tat antibody response profile on the x-axis. Statistical significance was tested using Nemenyi non-parametric test. * p , 0.05 comparing HIV+Tat- and HIV- groups. #p , 0.05 comparing HIV- group. doi:10.1371/journal.pone.0060825.gTat Antibody Responses to HIV-1 InfectionTable 1. Percent inhibition of Tat-transactivation after depleting anti-Tat antibodies and IgG fractions of the plasma.inhibition ( )a 74.01 76.83 80.95 70.36 82.45 78.60 74.54 72.19 70.28 68.27 inhibition ( )b 27.59 30.87 13.68 38.43 22.74 17.25 26.36 19.14 11.31 16.95 inhibition ( )c 43.85 39.63 20.54 47.42 36.72 15.37 37.31 38.95 17.29 13.profiles of response Full potential responseNo. 1 2Tat 3.216 1.166 0.774 1.861 0.681 0.476 1.561 1.706 0.264 0.Combined response (N preferred reaction)4 5 6 7N-specific response17monoclonal Tat antibody2.75.12.11.HIV+Tat-1 2 3 4 5 6 7 8 90.065 0.06 0.051 0.053 0.058 0.053 0.054 0.067 0.063 0.22.55 18.18 9.41 26.37 17.66 7.33 15.79 23.28 13.75 12.20.12 15.20 8.57 19.26 15.33 10.02 11.78 12.12 14.00 10.18.70 19.12 7.31 22.12 13.15 9.87 9.96 17.83 12.26 12.HIV-1 2 3 4 5 6 7 8 90.087 0.076 0.058 0.071 0.072 0.071 0.083 0.064 0.087 0.11.47 18.59 23.43 8.39 19.34 3.23 15.55 24.93 16.72 9.12.42 10.78 18.72 10.80 16.54 5.33 10.40 15.87 17.80 11.13.16 17.89 21.10 7.89 13.32 7.88 7.97 16.89 14.38 7.All sera were diluted at 1:50 for Tat-neutralization assay. The ELISA OD values and inhibition of Tat-transactivation (inhibition ( )) are shown. “No.” represents the number of each plasma sample. a inhibition of Tat-transactivation after depleting non-specific Tat antibodies with coated pPEPTIDE2 by ELISA. b inhibition of Tattransactivation after depleting Tat antibodies with coated Tat by ELISA. c inhibition of Tat-transactivation after depleting IgG fractions with coated protein G by ELISA. doi:10.1371/journal.pone.0060825.twhich reacted with 14.3, 33.3 and 59.5 of the Tat-seropositive samples, respectively (Fig. 2b, 3a). Moreover, all Tat(1?1) positive samples were both Tat(1?8) and Tat(1?6) positive, and all Tat(1?1) or Tat(1?6) positive samples were Tat(1?8) positive (Fig. 3a). This gradient of antigenicity was also present in the reactivity levels (Fig. 3a): all Tat(1?1) samples that exhibited either strong or moderate binding reactivity also exhibited strong or moderate binding reactivity to both Tat(1?8) and Tat(1?6), and all samples that exhibited either strong or moderate binding reactivity to Tat(1?1) or Tat(1?6) also exhibited either strong or moderate binding reactivity to Tat(1?8). 12926553 Comparing the reactivity patterns of the N antigens to each other as well as to that of fulllength Tat, Tat(1?8) and Tat(1?6) showed almost the samereactive patterns, which had a correlation coefficient value (R) of 0.941 (Fig. 3b). To our surprise, both Tat(1?8) and Tat(1?6) had highly similar reactivity patterns compared to full-length Tat, with the R values of 0.946 and 0.949, respectively. This strongly suggests that the important B-cell epitopes of full-length Tat are found in 1?8 aa. In contrast to the N antigens, the ant.
