Production of Humanized Mouse via Thymic Renal Capsule Grafting, CD34⁺ Cells Injection, and Cytokine Delivery

Intravital Two-Photon Microscopy of the Native Thymus

“…Ex vivo culture systems (Hong & Moore, 1996;Ramsdell et al, 2006) including thymic slices (Bhakta et al, 2005;Ehrlich et al, 2009;Fournier et al, 2020;Le Borgne et al, 2009;Markert et al, 1997;Zhou et al, 2020) and whole organ imaging (Campinoti et al, 2020;Dzhagalov et al, 2012) are very powerful systems for studying certain aspects of thymus biology such as thymocyte-stromal interactions (Ladi et al, 2008;Nakagawa et al, 2012) and T cell development (Le Borgne et al, 2009;Witt et al, 2005), but these techniques lack blood flow and may not fully recapitulate the in vivo situation. Due to a lack of viable intravital imaging methods for the native thymus, researchers have relied on thymus transplantation to optically accessible sites including the kidney capsule (Caetano et al, 2012;Gregorio et al, 2021;Iwai & Inaba, 2015;Morillon et al, 2015), anterior chamber of the eye (Oltra & Caicedo, 2018), and pinna of the mouse ear (Chen et al, 2013) for intravital microscopy, but transplantation may alter the native vascular connections and exposes the tissue to an aberrant environment (Caetano et al, 2012;Vollmann et al, 2021). Although it has been reported that the transplanted thymus mirrors the endogenous thymus in architecture and vascularity, direct measurement of hemodynamic parameters in the native thymus is yet to be reported (Vollmann et al, 2021).…”