CD4 T lymphocyte activation in BLV-induced persistent B lymphocytosis in cattle.
Bovine leukemia virus (BLV) is an oncogenic retrovirus in the human T cell leukemia virus family. BLV infects B lymphocytes and induces a nonmalignant persistent lymphocytosis (PL) and leukemia/lymphoma in cattle. There is evidence that CD4 T lymphocytes are activated during BLV infection and promote the development of PL. How CD4 T lymphocytes are activated by BLV infection is not known. We observed that CD4 T lymphocytes from PL cattle proliferated in the presence of autologous, irradiated peripheral blood mononuclear cells (PBMC), whereas no proliferation occurred in cell cultures from BLV-infected non-PL cattle. Proliferation required direct contact with metabolically active irradiated PBMC but was not associated with viral protein expression or inhibited by antibodies to BLV. Unexpectedly, B lymphocytes alone failed to account for the irradiated PBMC stimulation of CD4 T lymphocytes. These observations and the magnitude of the proliferative response suggest that activation is polyclonal and involves mechanisms other than BLV antigen-specific stimulation.
Stone
D M
DM
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, 99164-7040, USA.
Norton
L K
LK
Chambers
J C
JC
Meek
W J
WJ
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000914:Antibodies, Viral / Q000494:pharmacology; D001402:B-Lymphocytes / Q000473:pathology* / Q000821:virology*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002417:Cattle; D016583:Enzootic Bovine Leukosis / Q000276:immunology* / Q000473:pathology*; D005802:Genes, MHC Class II; D007106:Immune Sera / Q000494:pharmacology; D007108:Immune Tolerance / Q000187:drug effects; D007376:Interleukin-2 / Q000276:immunology; D001909:Leukemia Virus, Bovine / Q000276:immunology / Q000502:physiology*; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000528:radiation effects; D008213:Lymphocyte Activation
D000906:Antibodies; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D001426:Bacterial Proteins; D007106:Immune Sera; D007376:Interleukin-2; C095564:Map protein, Staphylococcus aureus