Preliminary assessment of correlation between T-lymphocyte responses and control of porcine reproductive and respiratory syndrome virus (PRRSV) in piglets born after in-utero infection of a type 2 PRRSV

ABSTRACT

A preliminary study into the protective mechanisms of adaptive immunity against porcine reproductive and respiratory syndrome virus (PRRSV) in piglets (n = 9) born to a gilt challenged intranasally with a type-2 PRRSV. Immune parameters (neutralizing antibodies, CD3⁺CD4⁺, CD3⁺CD8⁺, CD3⁺CD4⁺CD8⁺ T-lymphocytes, and PRRSV-specific interferon (IFN)-γ secreting T-lymphocytes) were compared with infection parameters (macro- and microscopic lung lesion, and PRRSV-infected porcine alveolar macrophages (CD172α⁺PRRSV-N⁺ PAM) as well as with plasma and lymphoid tissue viral loads. Percentages of three T-lymphocyte phenotypes in 14-days post-birth (dpb) peripheral blood mononuclear cell (PBMC) had significant negative correlations with percentages of CD172α⁺PRRSV-N⁺ PAM (p 0.1) with infection parameters. The results indicate that T-lymphocytes contribute to controlling PRRSV replication in young piglets born after in-utero infection.