SHORT COMMUNICATION Expression of mucins on the mucosal surface of lungs of 4-week-old pigs Chung Hyun Kim & Kichan Lee & Kiwon Han & Yeonsu Oh & Duyeol Kim & Hwi Won Seo & Changhoon Park & Mi-Kyoung Ha & Sung-Hoon Kim & Kyung-Dong Cho & Bog-Hieu Lee & Chanhee Chae Accepted: 31 January 2011 /Published online: 18 February 2011 # Springer Science+Business Media B.V. 2011 Abstract The aim of this study was to determine the immunoreactivity of normal small bronchial, bronchiolar, respiratory bronchiolar, and interalveolar epithelium using anti- bodies to six mucins: MUC1, MUC2, MUC4, MUC5AC, MUC5B, and MUC6. The large, gel-forming secreted mucins MUC2, MUC5AC, and MUC5B were widely expressed in the lower respiratory tract. The results of this study demonstrate that these secreted mucins form a gel to cover and protect the mucosal surface in the lower respiratory tract of pigs. Keywords Lung . Mucin . Swine Introduction Mucins are membrane-bound or secreted products that are synthesized by secretory epithelial cells and cover the airway luminal surface to protect epithelial surfaces against harmful agents that may disrupt epithelial integrity (Rose 1992). They are highly glycosylated and responsible for the viscoelasticity of mucus (Rose and Voynow 2006). To date, at least 20 genes that code for mucin proteins have been identified in humans and have been designated as MUC1, MUC2, MUC3A, MUC3B, MUC4, MUC5AC, MUC5B, MUC6, MUC13, MUC15, MUC17, MUC19, and MUC20 (Hollingsworth and Swanson Vet Res Commun (2011) 35:255–260 DOI 10.1007/s11259-011-9465-y Chung Hyun Kim and Kichan Lee made an equal contribution to this work, they are co-first authors. C. H. Kim : K. Lee : K. Han : Y. Oh : D. Kim : H. W. Seo : C. Park : C. Chae (*) Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 599 Gwanak-ro, Gwanak-Gu, 151-742, Seoul, Republic of Korea e-mail: swine@snu.ac.kr M.-K. Ha : S.-H. Kim College of Oriental Medicine, Kyunghee University, 1 Hoegi-dong, Dongdaemun-ku, 130-701, Seoul, Republic of Korea K.-D. Cho : B.-H. Lee Department of Food and Nutrition, Chung-Ang University, Nae-Ri 72-1, Daedeok-Myeon, 456-756, Gyeonggi-Do, Republic of Korea