Article ID Journal Published Year Pages File Type
2462172 Veterinary Immunology and Immunopathology 2011 10 Pages PDF
Abstract

Bovine neonatal pancytopenia (BNP) is an emerging calf disease of unknown cause characterized by a pronounced susceptibility to bleeding as a result of a pancytopenia and bone marrow depletion. In this study we investigated whether this phenomenon is related to colostrum-derived alloantibodies directed against neonatal leukocytes. In a first experiment and using a flow cytometric approach sera from 6 BNP-dams (had given birth to BNP-calves; vaccinated against bovine viral diarrhea virus [BVDV]) and 6 control-dams (no herd history of BNP; no BVDV vaccination) were analyzed for the presences of alloantibodies (IgG) able to bind to the surface of leukocytes isolated from 7 calves from a herd with no history of BNP (no BVDV vaccination). In a second experiment, 4 neonates from 3 BNP-dams were fed colostrum from their corresponding mothers and sampled on a regular basis from birth up to day 21 of life under clinically controlled conditions. Sample analysis of the 4 neonates included hematology (white blood cell count and platelets), bone marrow cytology and histopathology as well as the flow cytometric detection of the percentage of IgG+-lymphocytes/monocytes in the peripheral blood. Experiment #1 showed that all BNP-dam sera harbored significantly higher alloantibody titers than the control dam sera (p < 0.001). In the peripheral blood of the two neonates (Experiment #2), the percentage of IgG+-cells increased dramatically within 12 h post colostrum intake (p.c.i.), remaining at over 95% for up to 3 days. Both calves developed BNP-associated clinical symptoms, one died. Both twin calves showed no clinical symptoms accompanied by a minor increase of IgG+ cells for up to 12 h. Thus, the level of IgG+-cells and the duration of the detection thereof correlated with the severity of BNP developed by these animals. The results show that BNP-dams harbor alloantibodies against surface antigens of neonatal leukocytes in their sera that are readily transferred to the offspring via colostrum. These alloantibodies probably play a crucial role in the pathogenesis of BNP.

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