Figure 4

Detection of an antibody response to MSBI1.176 Rep protein in human plasma. (a) Thirty human plasma samples were screened for an anti-MSBI1.176 Rep protein antibody response using ELISA assays. The signal intensity is given in arbitrary units (a.u.). Signals are ordered by size and the standard deviation is given based on technical triplicates. The average signal and the sum of average signal and standard deviation of all plasma samples are indicated as dotted lines. Statistical significance as compared to background signal was assessed by student’s t-test from technical triplicates. *p < 0.05; **p < 0.01; ***p < 0.001. (b) Quantification of anti-MSBI1.176 Rep protein antibody titers in human plasma. A dilution series (1:1.000 to 1:128.000) of plasma sample # 30 (see panel (a)) was tested for anti-MSBI1.176 Rep reactivity (black) in ELISA assays as compared to reactivity against BSA (white). Statistical significance was assessed by student’s t-test. *p < 0.05; **p < 0.01; ***p < 0.001; n.s. not significant. (c) Analysis of anti-Rep specificity of human plasma antibodies. The MSBI1.176 Rep protein coated on ELISA plates was pre-incubated with increasing amounts of an anti-Rep mouse monoclonal antibody pool prior to ELISAs with the human plasma samples #30, #1, #24 and #25. ELISAs with Rep protein lacking a pre-incubation were used as a control reaction (no mAB), whose signal was set to 100%. Statistical significance of the difference to this control reaction were calculated using a paired student’s t-test. *p < 0.05; **p < 0.01.