Differences between B cell and macrophage transformation by the bovine parasite, Theileria annulata: a clonal approach.
Theileria annulata, a tick-transmitted protozoan parasite, infects and transforms cells of the hemopoietic system, particularly those of the B cell and monocyte/macrophage lineages. Here, the effect of infection/transformation on the resulting phenotype was studied using a clonal approach. Three phenotypes of transformed cell lines could be discerned. The first is characterized by surface expression of IgM, CD21, and the B cell epitopes, B-B2 and B-B8, Ig heavy chain gene rearrangement, and mRNA expression. Such lines were obtained from fresh and cultured PBMC and at increased frequency from purified B cells, but never from fetal bone marrow cells. The second phenotype can be distinguished from the first by the absence of Ig heavy chain expression and reduced surface expression of B cell markers (CD21, B-B2, B-B8). Clones with this phenotype were obtained from transformed fetal bone marrow cells only. The third phenotype showed an absence of all of the above B cell markers, including surface IgM, and a lack of Ig heavy chain gene rearrangement. The latter clones could be maintained for several weeks after elimination of T. annulata by BW720c treatment, and they reacquired a macrophage-like phenotype. This implies that parasite-induced dedifferentiation is restricted to monocyte/macrophage, and that B cell markers are indicative of cell lineage progeny. Demonstration of surface IgM on PBMC-derived B cell clones suggests that infection of B cells with T. annulata may be an epigenetic method to immortalize ruminant B cells of a defined Ag specificity.
Sager
H
H
Institute of Veterinary Virology, University of Berne, Switzerland.
Bertoni
G
G
Jungi
T W
TW
D000818:Animals; D000954:Antigens, Surface / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000469:parasitology*; D015415:Biomarkers / Q000032:analysis; D002417:Cattle; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002461:Cell Line, Transformed; D002999:Clone Cells / Q000276:immunology / Q000378:metabolism / Q000469:parasitology; D015322:Gene Rearrangement, B-Lymphocyte; D005803:Genes, Immunoglobulin; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism / Q000469:parasitology*; D016796:Theileria annulata / Q000276:immunology*; D014158:Transcription, Genetic / Q000276:immunology
D000954:Antigens, Surface; D015415:Biomarkers