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Updated: Aug 9, 2026
Murine Model of CD40-activation of B cells
Published on: March 6, 2010
CD5+ B cells from bovine leukemia virus infected cows are activated cycling cells responsive to interleukin 2
J P Matheise1, M Delcommenne, A Mager
1Department of Immunology, University of Namur, Belgium.
Insights
Bovine leukemia virus (BLV) infection activates B cells in cows with persistent lymphocytosis (PL). These CD5+ B cells show myeloid markers and cell cycle progression, indicating an activated state.
Area of Science:
- Veterinary Immunology
- Bovine Leukemia Virus Research
- Cellular Immunology
Background:
- Bovine leukemia virus (BLV) causes persistent lymphocytosis (PL) in infected cows.
- B cells in PL typically express the CD5 T-cell marker, but their activation status was unclear.
Purpose of the Study:
- To determine if CD5+ B cells in BLV-infected cows with PL are in an activated state.
- To investigate the membrane phenotype and cell cycle status of these B cells.
Main Methods:
- Flow cytometry using CD5, CD11b, and CD11c markers.
- Cell cycle analysis.
- In vitro proliferation assays using IL-2 supernatant on T-cell-depleted peripheral blood mononuclear cells.
Main Results:
- CD5+ B cells in BLV-infected cows also expressed myeloid markers CD11b and CD11c.
- Over 15% of these B cells showed cell cycle progression beyond the resting G0/G1 phase.
- T-cell-depleted cells proliferated in response to IL-2, suggesting B-cell activation.
Conclusions:
- CD5+ B cells in BLV-infected cows with PL exhibit an activated phenotype.
- These findings suggest a role for activated B cells in the pathogenesis of BLV-associated lymphocytosis.
Abstract:
Most of the B cells from bovine leukemia virus (BLV) infected cows in persistent lymphocytosis (PL) were known to express the CD5 T-cell marker but it was not known whether this peculiar membrane phenotype relates to an activation state. It was demonstrated that these B cells were also flagged by two other membrane markers normally borne by cells belonging to the myeloid lineage (namely CD11b and CD11c). Moreover, cell cycle analysis illustrated that a significant percentage of these B cells (greater than 15%) left their resting (G0/G1) status and progressed through the cell cycle. In addition, T-cell-depleted peripheral blood mononuclear cells from animals in PL were shown to proliferate in response to a IL-2-containing supernatant (MLA 144). These results indicate that the CD5+ B cells from BLV-infected cows in PL are activated cells.
