Fig 4. Humoral and cellular immune response against CSFV infection.

(a) Antibody response to E2 glycoprotein detected by ELISA (IDEXX) after infection (in blocking %). Values greater than 40% blocking were considered positive. (b) Neutralising antibody titres against PR (pigs 1 to 14 and sow PR) and Cat01 (pigs 16 to 28 and sow Cat) CSFV strains at 3 and 4 weeks p.i. (c) Lack of IFN- γ response by ELISPOT assay in CSFV postnatally persistently infected piglets and detection of effective response in immunocompetent pigs from the PR group at 4 weeks p.i. A total of 5x10⁵ PBMCs/well were plated in triplicates at 0.1 multiplicity of infection (MOI) of CSFV homologous strains: PR strain (samples from pigs 1 to 14 and sow PR) and Cat01 strain (samples from pigs 17 to 27 and sow Cat). Moreover, the samples were incubated in the presence of Thiverval strain at 0.01 MOI and phytohaemagglutinin (PHA) (10 μg/ml). Asterisk symbol indicates the sample from pig 28 analysed at 19 dpi.