Tissue-resident memory T cells trigger rapid exudation and local antibody accumulation.

Adaptive immunity is didactically partitioned into humoral and cell-mediated effector mechanisms, which may imply that each arm is separate and does not function together. Here, we report that the activation of CD8+ resident memory T cells (T _RM ) in nonlymphoid tissues triggers vascular permeability, which facilitates rapid distribution of serum antibodies into local tissues. T _RM reactivation was associated with transcriptional upregulation of antiviral signaling pathways as well as Fc receptors and components of the complement cascade. Effects were local, but evidence is presented that T _RM in brain and reproductive mucosa are both competent to induce rapid antibody exudation. T _RM reactivation in the mouse female genital tract increased local concentrations of virus-specific neutralizing antibodies, including anti-vesicular stomatitis virus, and passively transferred anti-HIV antibodies. We showed that this response was sufficient to increase the efficacy of ex vivo vesicular stomatitis virus neutralization. These results indicate that CD8+ T _RM antigen recognition can enhance local humoral immunity.
(Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)