Enhanced infectivity of bovine viral diarrhoea virus (BVDV) in arginase-producing bovine monocyte-derived macrophages

Macrophages are important cells of the innate immunity that play a major role in Bovine Viral Diarrhoea Virus (BVDV) pathogenesis. Macrophages are not a homogenous population; they exist in different phenotypes, typically divided into two main categories: classically (pro-inflammatory) and alternatively activated (anti-inflammatory) or M1 and M2, respectively. The role of bovine macrophage phenotypes on BVDV infection is still unclear. This study characterized the interaction between BVDV and monocyte-derived macrophages (Mo-Mφ) collected from healthy cattle and polarized to an M1 or M2 state by using LPS, INF-γ, IL-4, or azithromycin. Arginase activity quantitation was utilized as a marker of the M2 Mo-Mφ spectrum. There was a significant association between arginase activity and the replication rate of BVDV strains of different genotypes and biotypes. Inhibition of arginase activity also reduced BVDV infectivity. Calves treated with azithromycin-induced Mo-Mφ of the M2 state produced high levels of arginase. Interestingly, azithromycin administered in vivo increased the susceptibility of macrophages to BVDV infection ex vivo. Mo-Mφ from pregnant dams and calves produced higher arginase levels than those from non-pregnant adult animals. The increased infection of arginase-producing alternatively activated bovine macrophages with BVDV supports the need to delve into a possible leading role of M2 macrophages in establishing the immune-suppressive state during BVDV convalescence.

Instituto de Virología

Fil: Barone, Lucas Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; Argentina

Fil: Barone, Lucas Jose. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Cardoso, Nancy Patricia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; Argentina

Fil: Cardoso, Nancy Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Mansilla, Florencia Celeste. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; Argentina

Fil: Mansilla, Florencia Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Castillo, Mariangeles. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; Argentina

Fil: Castillo, Mariangeles. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Capozzo, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Virología e Innovaciones Tecnológicas; Argentina

Fil: Capozzo, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina