Association of lymphopenia with porcine circovirus type 2 induced postweaning multisystemic wasting syndrome (PMWS).
The composition of peripheral blood leukocyte populations was studied following experimental PCV2-infection in 3-week-old piglets. Four of 10 PCV2-infected piglets developed clinical and pathological symptoms consistent with postweaning multisystemic wasting syndrome (PMWS) between 14 and 21 days post-inoculation (p.i.), and were characterised as PMWS-affected. Only these four PMWS-affected piglets, but neither the non-symptomatic infected nor control animals, developed a clear leukopenia. Kinetic analysis demonstrated a clear loss of both CD21(+) B and CD3(+) T lymphocytes in the PMWS-affected piglets. By CD3/CD4/CD8 triple labelling, the influence of PCV2 infection on all T cell sub-populations was discernible. A loss of CD3(+)CD4(+)CD8(+) memory/activated Th lymphocytes was particularly notable. However, all T lymphocyte sub-populations-CD3(+)CD4(+)CD8(+) memory Th, CD3(+)CD4(+)CD8(-) nai;ve Th, CD3(+)CD4(-)CD8(+) Tc and CD3(+)CD4(-)CD8(-) gammadelta TCR(+) lymphocytes-were susceptible to PCV2 infection-induced lymphopenia. CD3(-)CD4(-)CD8(+) NK cells were also depleted in the PMWS-affected animals, but granulocytes and monocytes were less affected. In conclusion, PCV2 infection induces primarily a lymphopenia, but only in animals which subsequently develop PMWS. The lymphopenia can be identified early p.i., particularly with the B lymphocytes. Memory/activated Th lymphocytes might be affected more than the other T cell sub-populations, but as time progressed a collapse of both T and B cell populations was clear.
Nielsen
J
J
Department of Virology, Danish Veterinary Institute, Lindholm, DK-4771, Kalvehave, Denmark.
Vincent
I E
IE
Bøtner
A
A
Ladekaer-Mikkelsen
A-S
AS
Allan
G
G
Summerfield
A
A
McCullough
K C
KC
D000818:Animals; D018173:Circoviridae Infections / Q000097:blood / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000254:growth & development*; D005434:Flow Cytometry / Q000662:veterinary; D006433:Hemocyanins / Q000276:immunology; D007114:Immunization / Q000662:veterinary; D007700:Kinetics; D007958:Leukocyte Count / Q000662:veterinary; D016131:Lymphocyte Subsets / Q000276:immunology / Q000821:virology; D008231:Lymphopenia / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D011897:Random Allocation; D013047:Specific Pathogen-Free Organisms; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000821:virology*; D019282:Wasting Syndrome / Q000097:blood / Q000276:immunology / Q000662:veterinary* / Q000821:virology
D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin