Bovine leukemia virus replicates in sheep B lymphocytes under a T cell released factor.
In order to determine which cell supports BLV replication in experimentally infected sheep, peripheral blood lymphocytes (PBL) were separated into purified B and T populations by a panning technique. Our data demonstrate that viral replication takes place only in B lymphocytes. However, PHA, a T cell mitogen, is necessary for BLV replication both in PBL and enriched surface immunoglobulin bearing cells, whereas B cell mitogens have no effect on viral replication. Altogether, these results suggest that BLV activation in enriched B lymphocytes is dependent on the presence of residual T cells, and occurs through a T cell interaction, probably mediated by a soluble factor. This possibility was confirmed by the fact that the conditioned medium from cultures of BLV-free sheep T lymphocytes greatly enhances viral production by infected B lymphocytes. Our data favor the hypothesis that BLV multiplication occurs through the regular activation mechanisms of the immune system.
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D001402:B-Lymphocytes / Q000382:microbiology*; D002450:Cell Communication; D001909:Leukemia Virus, Bovine / Q000254:growth & development*; D007942:Leukemia, Experimental / Q000503:physiopathology; D010835:Phytohemagglutinins / Q000494:pharmacology; D012190:Retroviridae / Q000254:growth & development*; D012756:Sheep; D013601:T-Lymphocytes / Q000502:physiology*; D014775:Virus Activation; D014779:Virus Replication
D000956:Antigens, Viral; D010835:Phytohemagglutinins