Le Jan C
Laboratoire de Pathologie Infectieuse et d'Immunologie, Institut National de la Recherche Agronomique, Nouzilly, France.
Res Vet Sci. 1993 Nov;55(3):265-70. doi: 10.1016/0034-5288(93)90092-t.
Secretory component (SC) and IgA expression of epithelial cells were studied in the mammary tissue and mammary secretions of sows. In mammary tissue, SC was not detected until day 105 of gestation. From the time of delivery (day 115) to the time of established lactation, the proportion of epithelial cells containing SC rose from 20 per cent to nearly 100 per cent. There was no IgA in alveolar epithelial cells until day 105 of gestation; on day 115, IgA positive epithelial cells were present in 10 per cent of the alveoli, which increased to 80 per cent during lactation. Epithelial cells represented more than 20 per cent of the total cells in colostrum, and predominated over leucocytes in milk. In colostrum, these epithelial cells (9 to 15 microns) showed weakly positive membrane, SC, contained cytoplasmic SC and had a limited capacity for in vitro proliferation. Ten per cent of epithelial cells contained intracytroplasmic IgA. In milk, the epithelial cells were larger (15 to 40 microns) with a higher expression of both membrane and intracytoplasmic SC; 66 per cent of these cells expressed intracytoplasmic IgA. These data showed that the capacity of mammary epithelium to process IgA to secretory IgA was complete at the end of mammary gland organisation, and established that the epithelial cells of milk contribute to the transfer of IgA to neonates.
对母猪乳腺组织和乳腺分泌物中的分泌成分（SC）及上皮细胞IgA表达进行了研究。在乳腺组织中，直到妊娠第105天才检测到SC。从分娩时（第115天）到泌乳确立时，含有SC的上皮细胞比例从20%升至近100%。直到妊娠第105天，肺泡上皮细胞中均未检测到IgA；在第115天，10%的肺泡中存在IgA阳性上皮细胞，泌乳期间该比例增至80%。上皮细胞占初乳中细胞总数的20%以上，且在乳汁中比白细胞占优势。在初乳中，这些上皮细胞（9至15微米）膜呈弱阳性，含有SC，胞质内也有SC，且体外增殖能力有限。10%的上皮细胞含有胞质内IgA。在乳汁中，上皮细胞更大（15至40微米），膜和胞质内SC的表达更高；其中66%的细胞表达胞质内IgA。这些数据表明，乳腺上皮将IgA加工成分泌型IgA的能力在乳腺组织发育结束时已完善，并证实乳汁中的上皮细胞有助于将IgA传递给新生儿。
