Western blot of PrPSc in tissue homogenates of brainstem, uterine caruncular endometrium, and placental cotyledonary chorioallantois of pregnant and non-pregnant ewes with or without scrapie. Protein from 0.5 mg brainstem or 30 mg endometrium, chorioallantois, and other tissues was loaded in each lane. PK (20 μg/ml) treatment at 37°C for 30 min of each tissue homogenate is indicated at the bottom of each panel (+). (A) Western blot of tissue homogenates prepared from brainstem (lanes 1 and 2), uterine caruncular endometrium (lanes 3–5), and cotyledonary chorioallantois (lanes 6–8) of an uninfected ewe (171QQ) pregnant (day 145 post mating) with a 171QQ conceptus. Samples in lanes 4, 5, 7, and 8 were prepared with sarkosyl and ultracentrifugation. Tissue homogenates were with (lanes 2, 5, and 8) or without (lanes 1, 3, 4, 6, and 7) PK treatment. (B) Western blot of tissue homogenates of brainstem (lanes 1 and 2), endometrium (lanes 3–5), and myometrium (lanes 6–8) of a non-pregnant scrapie-infected ewe (171QQ). Samples in lanes 4 and 5 and in lanes 7 and 8 were prepared with sarkosyl and ultracentrifugation. Tissue homogenates were with (lanes 2, 5, and 8) or without (lanes 1, 3, 4, 6, and 7) PK treatment. (C) Western blot of tissue homogenates prepared from brainstem, caruncular endometrium, and cotyledonary chorioallantois of a scrapie-infected ewe (177QQ) pregnant with a 171QQ conceptus. Lanes 1 and 2, brainstem prepared without sarkosyl and ultracentrifugation; lanes 3 and 4, uterine caruncular endometrium prepared with sarkosyl and ultracentrifugation; and lanes 5 and 6, placental cotyledonary chorioallantois prepared with sarkosyl and ultracentrifugation. Tissue homogenates were with (lanes 2, 4, and 6) or without (lanes 1, 3, and 5) PK treatment. (D) Western blot of tissue homogenates prepared from brainstem, caruncular endometrium, and cotyledonary chorioallantois of a scrapie-infected ewe (177QQ) pregnant with a 171QR conceptus. Lanes 1 and 2 (brainstem), prepared without sarkosyl and ultracentrifugation; lanes 3 and 4 (uterine caruncular endometrium), prepared with sarkosyl and ultracentrifugation; and lanes 5 and 6, placental cotyledonary chorioallantois prepared with sarkosyl and ultracentrifugation. Tissue homogenates were with (lanes 2, 4, and 6) or without (lanes 1, 3, and 5) PK treatment.