Figure 3.

Phage-inhibitory effect of healthy humans’ plasma. Plasma were collected from 55 healthy donors never subjected to phage therapy, (A) frequency of phage-inhibitory effect in the investigated donors, (B) strength of phage inhibition by the investigated plasma: average phage titer after incubation with positive (containing phage-neutralizing antibodies) and negative (not containing phage-neutralizing antibodies) plasma. Positive plasma – inactivating the phage (phage titer after incubation was lower than the range of the negative samples); 16 samples were classified into this group in the case of A3R and 19 in 676Z. Negative plasma – not inactivating phage (phage titer after incubation was within the range: mean value of the control +/- 2 x SD); 39 samples could be classified into this group in the case of A3R and 36 in 676Z. Control was calculated from titers of the same phage preparation incubated with commercial fetal bovine serum samples (N = 8). The error bars represent mean ± standard deviation (SD).