Figure 4From: Characterization of homologous and heterologous adaptive immune responses in porcine reproductive and respiratory syndrome virus infection Individual responses in the IFN-γ ELISPOT after second challenge that took place at day 84 pi. Bars depict individual frequencies of virus-specific IFN-γ secreting cells after the homologous and heterologous challenge for this experiment. ELISPOTs were performed with both strains used in the present study.Back to article page