Airway smooth muscle is fundamental for maintaining airway tone. The specialized ultrastructural features and regulatory mechanisms of airway smooth muscle are vital for normal airway function. Patients with respiratory disorders, such as severe asthma, exhibit the distinguishing feature of increased bronchial smooth muscle mass. The increase in smooth muscle mass is related either to abnormal bronchial smooth muscle cell (BSMC) proliferation or the accumulation of contractile protein. Smooth muscle cell proliferation is an important component of airway remodeling in asthma and is consequently a target for the development of novel anti-asthma agents. Airway smooth muscle cells express CT-1 and release GM-CSF, RANTES and IL-8 in vitro. In order to develop therapies for asthma, researchers have utilized BSMC to elucidate the cellular and molecular mechanisms underlying BSMC proliferation. HBSMC from ScienCell Research Laboratories are isolated from human bronchi and bronchioles. HBSMC are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HBSMC are characterized by immunofluorescence with antibodies specific to α-smooth muscle actin. HBSMC are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HBSMC are guaranteed to further expand for 15 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Smooth Muscle Cell Medium (SMCM, Cat. #1101) for culturing HBSMC in vitro.