Figure 4.
Passive transfer of neutralizing antibodies reduces viremia. PRRSV RNA quantification from serum by RT-qPCR for (A) genotype 2 MN184, and (B) genotype 1 SDEU, in PRRSV-naïve pigs administered neutralizing immune Ig (n= 12), non-neutralizing immune Ig (n= 12), PRRSV-negative or no Ig (combined control groups, n= 8). Difference in mean viremia between groups receiving neutralizing Ig or not (pooled non-neutralizing and negative Ig) was compared by one-tailed Mann Whitney test of area under the curve. AUC day 0–21 for MN184, p=0.0145. AUC day 0–21 for SDEU, p=0.03. Numbers above the X-axis are percent reduction at the indicated day after challenge. Dotted lines indicate the RT-PCR assay sensitivity limit for MN184 (A) or SDEU (B).