Virus growth kinetics of the porcine reproductive and respiratory syndrome virus 1 (PRRSV-1) Lleida 029_22 strain in MARC-145, porcine primary alveolar macrophage (PAMs) and PAM-KNU cells.

Cell cultures were infected with the Lleida 029_22 strain at a multiplicity of infection (MOI) of 0.1. Culture supernatants were collected at the indicated time points and infected cells were stained with an anti-PRRSV N protein antibody. (A) The 72 h post-infection results were examined under a fluorescence microscope using a 20× objective. (B) Virus replication at each time point was quantified by titration in PAM-KNU cells. Data are presented as mean ± SD from three independent experiments.