Recent studies have characterized populations of memory CD8+ T cells that do not recirculate through the blood but are, instead, retained in nonlymphoid tissues. Such CD8+ tissue resident memory T cells (TRM) are critical for pathogen control at barrier sites. Identifying TRM and defining the basis for their tissue residency is therefore of considerable importance for understanding protective immunity and improved vaccine design. Expression of the molecule CD69 is widely used as a definitive marker for TRM, yet it is unclear whether CD69 is universally required for producing or retaining TRM. Using multiple mouse models of acute immunization, we found that the functional requirement for CD69 was highly variable, depending on the tissue examined, playing no detectable role in generation of TRM at some sites (such as the small intestine), whereas CD69 was critical for establishing resident cells in the kidney. Likewise, forced expression of CD69 (but not expression of a CD69 mutant unable to bind the egress factor S1PR1) promoted CD8+ TRM generation in the kidney but not in other tissues. Our findings indicate that the functional relevance of CD69 in generation and maintenance of CD8+ TRM varies considerably, chiefly dependent on the specific nonlymphoid tissue studied. Together with previous reports that suggest uncoupling of CD69 expression and tissue residency, these findings prompt caution in reliance on CD69 expression as a consistent marker of CD8+ TRM.
|Original language||English (US)|
|Number of pages||10|
|Journal||Journal of Immunology|
|State||Published - Aug 15 2019|
Bibliographical noteFunding Information:
This work was supported by National Institutes of Health Award R01AI38903 (to S.C.J.) and Training Grant T32AI007313 (to D.A.W.). H.B.d.S. was supported by a Paul C. Shiverick/Cancer Research Institute Irvington Fellowship. Address correspondence and reprint requests to Dr. Stephen C. Jameson, University of Minnesota, Center for Immunology, 2101 6th Street SE, Minneapolis, MN 55455. E-mail address: email@example.com
© 2019 by The American Association of Immunologists, Inc.