Generation and Preliminary Characterization of Immortalized Cell Line Derived from Rat Lymphatic Capillaries

Isolation of rodent endothelial cells from lymphatic capillaries with yields that allow extensive functional studies remains challenging due to low cell numbers, variable purity, and limited growth potential. The purpose of this study was the generation and preliminary characterization of rat lymphatic cell line with extended replicative capacity. This cell line is intended for in vitro studies of cellular transport in lymphatic endothelium and for in vivo experiments in rat animal models. Methods: We created a novel rat lymphatic immortalized cell line, SV40-LEC, using retroviral gene transfer of SV40 large T antigen. We confirmed expression of characteristic markers and then examined its growth and transport properties. Results: SV40-LECs demonstrated improved proliferative capacity, but retained morphological characteristics of lymphatic cells and expression of established lymphatic markers. The cells form capillary-like network in vitro. SV40-LEC monolayer has similar permeability to that of the primary initial lymphatics. Paracellular transport in SV40-LECs is limited for substances >70 kDa. Barrier properties of the SV40-LECs can be modulated by cyclic adenosine monophosphate and histamine, which are known to affect microvascular permeability. Conclusion: The SV40-LECs provide an excellent tool for in vitro studies of properties of lymphatic endothelium, and may be suitable for in vivo transplantation studies.