title: The comparative profile of lymphoid cells and the T and B cell spectratype of germ-free piglets infected with viruses SIV, PRRSV or PCV2.
abstract: Lymphocyte subsets isolated from germ-free piglets experimentally infected with swine influenza virus (SIV), porcine reproductive and respiratory syndrome virus (PRRSV) or porcine circovirus type 2 (PCV2) were studied and the profile of these subsets among these three infections was monitored. Germ-free piglets were used since their response could be directly correlated to the viral infection. Because SIV infections are resolved even by colostrum-deprived neonates whereas PRRSV and PCV2 infections are not, SIV was used as a benchmark for an effectively resolved viral infection. PRRSV caused a large increase in the proportion of lymphocytes at the site of infection and rapid differentiation of B cells leading to a high level of Ig-producing cells but a severe reduction in CD2-CD21+ primed B cells. Unlike SIV and PCV2, PRRSV also caused an increase in terminally differentiated subset of CD2+CD8α+ γδ cells and polyclonal expansion of major Vβ families suggesting that non-specific helper T cells drive swift B cell activation. Distinct from infections with SIV and PRRSV, PCV2 infection led to the: (a) prevalence of MHC-II+ T cytotoxic cells, (b) restriction of the T helper compartment in the respiratory tract, (c) generation of a high proportion of FoxP3+ T cells in the blood and (d) selective expansion of IgA and IgE suggesting this virus elicits a mucosal immune response. Our findings suggest that PRRSV and PCV2 may negatively modulate the host immune system by different mechanisms which may explain their persistence.
authors.forename: Marek
authors.initials: M
authors.lastname: Sinkora
authors.forename: John E
authors.initials: JE
authors.lastname: Butler
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Lager
authors.forename: Hana
authors.initials: H
authors.lastname: Potockova
authors.forename: Jana
authors.initials: J
authors.lastname: Sinkorova
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000821:virology*; D018173:Circoviridae Infections / Q000276:immunology* / Q000821:virology; D017925:Circovirus / Q000502:physiology; D005856:Germ-Free Life; D007694:Killer Cells, Natural / Q000821:virology*; D009975:Orthomyxoviridae / Q000502:physiology; D009976:Orthomyxoviridae Infections / Q000276:immunology* / Q000821:virology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000502:physiology; D013552:Swine; D013601:T-Lymphocytes / Q000821:virology*