Initial Viral Inoculum Determines Kinapse-and Synapse-Like T Cell Motility in Reactive Lymph Nodes

Abstract

T cell activation in lymphoid tissue occurs through interactions with cognate peptide-major histocompatibility complex (pMHC)-presenting dendritic cells (DCs). Intravital imaging studies using ex vivo peptide-pulsed DCs have uncovered that cognate pMHC levels imprint a wide range of dynamic contacts between these two cell types. T cell—DC interactions vary between transient, “kinapse-like” contacts at low to moderate pMHC levels to immediate “synapse-like” arrest at DCs displaying high pMHC levels. To date, it remains unclear whether this pattern is recapitulated when the immune system faces a replicative agent, such as a virus, at low and high inoculum. Here, we locally administered low and high inoculum of lymphocytic choriomeningitis virus (LCMV) in mice to follow activation parameters of Ag-specific CD4+ and CD8+ T cells in draining lymph nodes (LNs) during the first 72 h post infection. We correlated these data with kinapse- and synapse-like motility patterns of Ag-specific T cells obtained by intravital imaging of draining LNs. Our data show that initial viral inoculum controls immediate synapse-like T cell arrest vs. continuous kinapse-like motility. This remains the case when the viral inoculum and thus the inflammatory microenvironment in draining LNs remains identical but cognate pMHC levels vary. Our data imply that the Ag-processing capacity of draining LNs is equipped to rapidly present high levels of cognate pMHC when antigenic material is abundant. Our findings further suggest that widespread T cell arrest during the first 72 h of an antimicrobial immune responses is not required to trigger proliferation. In sum, T cells adapt their scanning behavior according to available antigen levels during viral infections, with dynamic changes in motility occurring before detectable expression of early activation markers.

CD8+ T cell priming in oral mucosa-draining lymph nodes supports systemic immunity

“…2C and 2D ). Such a behavior is consistent with interaction dynamics driven by high cognate pMHC levels displayed on APC (Henrickson et al, 2008; Sivapatham et al, 2019). Starting on d 2 post i.o.…”

“…2A , middle and right panel). As changes in dynamic T cell behavior act as sensitive indicator for priming and precede detectable expression of activation markers (Moreau and Bousso, 2014; Sivapatham et al, 2019), we performed 2PM of mandLN in C57BL/6 or CD11c-YFP recipients containing tdT + or dsRed + OT-I T cells and polyclonal control CD8 + T cells during the first 72 h post i.o. Lm-OVA infection.…”

Capturing T Lymphocytes’ Dynamic Interactions With Human Neural Cells Using Time-Lapse Microscopy

“…Other microscopic techniques such as laser scanning confocal microscopy provide higher resolution but present slower temporal acquisition which do not allow capturing the diversity of immune cell motility behaviors. Notably, the traveling speed of CD8 + T cells we measured was in the same range (0-28 µm/min) as what has been reported by others using in vitro and in vivo (two-photo microscopy) models (5,41,42). By using a small (35mm) dish with four compartments, several distinct culture conditions could be monitored while using a relatively small number of precious primary neural cells and T lymphocytes.…”

Moving beyond velocity: Opportunities and challenges to quantify immune cell behavior*

“…T cell behavior can be classified into four different categories: directed (high velocity, high meandering index), confined (low velocity, low meandering index), returning (low velocity, high meandering index), and stop‐and‐go (low velocity, high meandering index) 20,38 . Sivapatham et al 93 used a combination of these measurements to analyze T cell behavior during the first 72 hours after infection of high and low load of LCMV Clone 13 footpad injection. Intravital imaging of the popliteal LN showed that LCMV specific CD4 + and CD8 + T cells decreased in speed and meandering index and arrested only modestly with a low viral load.…”

“…Relevant applications and packages are listed in Table 2 high meandering index), confined (low velocity, low meandering index), returning (low velocity, high meandering index), and stopand-go (low velocity, high meandering index). 20,38 Sivapatham et al 93 DCs presenting antigen cannot be controlled. 5 Under these conditions, relatively simple measurements might not be sufficient to extract subtle changes in cell behavior.…”