Human natural killer (NK) cells play a critical role in the control of viral infection, particularly herpesviral infections such as Epstein-Barr virus (EBV). Their primary function of killing of virally infected target cells is mediated by the contact-dependent lysis through directed secretion of perforin and granzymes. Despite the demonstrated importance of their development and function, our understanding of how NK cells interact with other cells within tissue is limited by a lack of satisfying models for studying human immunity live and in situ. Significant challenges arise when trying to visualize cells within tissue, however it is highly relevant to human disease to find ways to better define how particularly innate immune cells migrate and exert their cytotoxic function. Our previous research has used 2D cell culture systems to define the importance of cell migration in human NK cell development. In this application, we propose the adoption of previously methods of secondary lymphoid tissue (tonsil) histoculture as a model to study human NK cell migration and function within an in vivolike tissue microenvironment using fast, low-toxicity imaging. We will combine our expertise in human developmental immunology with our technical skills in cutting-edge microscopy and image analysis to visualize human NK cells within autologous tissue and measure migration in 3 dimensions. We will additionally use multi-parametric imaging mass cytometry to localize cells within tissue (Aim 1). Further, we will extend our model to include infection of the tonsils with EBV, which will allow us to measure differences in cell migration and function between infected and uninfected tissue. By integrating infection of tissue histoculture with human EBV we will enable the study of human NK cells killing physiologically relevant targets within tissue (Aim 2). The generation of this novel model will advance future studies of human immunity and enable unprecedented insight into the behavior of immune cells within their tissue microenvironment.
Understanding how the human immune system functions to eliminate infections requires using human tissue as a model system. In this application we propose the use of human tonsils as a model to study how innate immune cells find and fight infection. We combine this model with high-resolution microscopy to provide new insights into how immune cells function in a uniquely human tissue microenvironment.