Figure 6

BNP antibody-dependent complement-mediated lysis of cells correlates with MHC class I expression.

Cells were stained with antibodies and subsequently incubated with rabbit complement for 30 minutes. Antibody-dependent complement-mediated killing was measured as the percentage DAPI positive cells using flow cytometry. (a) MDBK cells transduced with the viral TAP inhibitor UL49.5 (TAP inhibitor) and MDBK cells that were transduced with a control vector (Control) were stained with an anti-MHC class I mAb (PT85a). (b) TAP inhibitor and control cells were stained with sera from Pregsure© BVD-vaccinated BNP dams (BNP, n = 6) and with unvaccinated control sera (control, n = 4). The difference in complement-mediated killing of Control and TAP inhibitor MDBK cells by sera from BNP dams and of control MDBK cells between BNP and control sera was compared using a paired t-test and an unpaired t-test for unequal variance, respectively. (c) Peripheral blood leukocytes (PBLk) were stained with anti-MHC class I mAb (ILA88) or isotype control. The proportion of granulocytes (Gran) to PBMC is given. (d) PBLk from calves (<6 mnd, n = 3) were stained with Abs from different sources. MHC I, Anti-MHC class I mAb and isotype control. BNP serum (/BNP colostrum), serum (/colostrum) from a Pregsure© BVD-vaccinated BNP dam and serum (/colostrum) from an unvaccinated dam as isotype control. The proportion of Gran to PBMC between Ab and isotype control is compared using a paired t-test. Data are representative for several different BNP sera and BNP colostra. (e) Wild-type (WT) and B2M knockout (B2M KO) MDBK cells were stained with sera from Pregsure© BVD-vaccinated BNP dams (BNP, n = 6) and unvaccinated control sera (control, n = 4). The difference in complement-mediated killing of WT and B2M KO MDBK cells by sera from BNP dams and of B2M KO MDBK cells between BNP sera and control sera was compared using a paired t-test and an unpaired t-test for equal variance, respectively.