Poster Presentation 8th Australasian Virology Society Meeting and 11th Annual Meeting of the Australian Centre for Hepatitis & HIV Virology Meeting 2015

Intravital multiphoton imaging of Herpes Simplex virus clearance mediated by skin-resident memory CD8+ T cells (#218)

Ali Zaid 1 2 , William R Heath 1 , Scott N Mueller 1
  1. Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, VIC, Australia
  2. The Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia

Herpes Simplex virus (HSV-1), causative agent of the cold sore, is a Herpesvirus belonging to a group of highly prevalent pathogens among the adult population worldwide.  Localised viral infections such as HSV-1 lead to the activation and expansion of antigen-specific T cells, and the subsequent generation of memory T cell populations. In a mouse model of epicutaneous HSV-1 infection, a population of skin-resident memory T cells (TRM) forms in the skin following infection. These surviving HSV-1-specific TRM are found almost exclusively in the epidermis and follicular epithelium, and persist throughout the life of the mouse within a distinct epidermal niche1. To understand the mechanism of protection by TRM following viral challenge, we lodged HSV-1-specific transgenic T cells (gBT-I) TRM in the epidermis using skin irritant 2,3-dinitrofluorobenzene (DNFB). Using intravital multiphoton microscopy, combined with the use of fluorescent gBT-I TRM and HSV-1 constructs, we found that TRM interact with skin cells infected with recrudescent virus and display reduced motility. We imaged the kinetics of effector memory CD8+ T cells (TEM) recruitment using a photoconvertible fluorescent transgenic gBT-I system to enable the distinction between epidermal TRM and recruited, dermal TEM. We found that TRM remain localized in the epidermis throughout viral recrudescence, whereas recruited TEM were able to circulate in both dermal and epidermal compartments. Finally, to understand the contribution of TEM to the recall response, we depleted circulating TEM and analysed the migratory behaviour of TRM during viral recrudescence in the absence of TEM. Interestingly, we found that despite the absence of TEM, TRM interacted dynamically with epidermal HSV-infected keratinocytes, and retained their protective properties while remaining in the epidermis. Here we show previously unappreciated response dynamics of tissue-resident T cell recall using in vivo multiphoton microscopy, thus providing insights into the mechanisms of T cell memory recall and viral clearance upon pathogen challenge.

  1. 1. Zaid A, Mackay LK, Rahimpour A, Braun A, Veldhoen M, Carbone FR, Manton JH, Heath WR and Mueller SN (2014) “Persistence of skin resident memory T cells within an epidermal niche” Proc. Nat. Acad. Sci. U.S.A. 111(14):5307-12