Figure 5
Infectivity of milk cells from BLV-infected, healthy cows with our improved LuSIA using CC81-GREMG cells. A The proviral loads in blood and milk, and the improved LuSIA results of milk cells for 6 BLV-infected cattle without lymphoma (cows N1, K11, N5, K8, GDF211 and GDF349). B Typical visualization of the infectivity of milk cells from selected cows N1, K11, and N5 among 6 BLV-infected dam tested in this study using our improved LuSIA protocol. The cells remaining in the supernatants were pelleted at 800 × g (cows N1 and K11) or 1000×g (cow N5) for 30 min. Milk cells (1 × 105) were cultured with 1 × 104 CC81-GREMG cells with (+) or without (−) 1 µg/mL of PWM. After 5 days of co-culturing CC81-GREMG cells with milk cells, the cells were fixed in 3.6% formaldehyde/PBS with Hoechst 33342. Fluorescent syncytia were observed using an EVOS2 fluorescence microscope. +, more than two syncytia were observed in the milk cells. FLK-BLV cells, which were productively infected with BLV, were used as the positive control. The scale bars (white and yellow bar) signify 100 µm or 650 µm.