In contrast to the “textbook” version of immunology, we now appreciate that the immune system does far more than just kill pathogens. Immune cells are sensors for many kinds of perturbations and can aid return to equilibrium or cause pathological responses. Our group focuses on tissue-resident immunity, which supports organ homeostasis and acts as a first line of defense against pathogens and other dangers. Remarkably, resident leukocytes are locally maintained independent of the circulating immune system, allowing them to become uniquely adapted to their home tissue and positioning them as key players in organ homeostasis. We seek to understand how resident immunity is maintained and how it evolves throughout life. The lab currently focuses on three main projects:

Cytokine regulation of tissue-resident memory CD8 T cells (TRM).

We are studying how common gamma chain cytokines and their coreceptors collaboratively maintain TRM, building on our previous work (Jarjour et al, PNAS 2022. PMID: 36260745. Jarjour et al, Immunity 2025. PMID: 40023156).

Adaptation versus addiction of TRM to inflammatory cytokines.

We are exploring how TRM are affected by short-term increases in cytokine availability and whether they are permanently changed even after their environment returns to homeostasis.

Cellular and molecular regulation of tissue-resident leukocyte proliferation.

We are addressing whether the seemingly limitless proliferative capacity of TRM and tissue-resident macrophages is restricted to stem cell-like subsets or is more broadly shared across each population. We also seek to identify the cell-intrinsic and -extrinsic mechanisms that regulate this process (see also Jarjour et al, Nature Immunology 2019. PMID: 31061528)

The lab seeks to understand tissue-resident CD8⁺ T cells and macrophages in amenable animal models which can then be translated to the human immune system. We use a variety of approaches to study tissue residency across organ systems, including CRISPR and genetic models; flow cytometry (including for the cell cycle); transcriptional and epigenetic approaches; and infection (viral, bacterial, helminth) and other disease models. 

• NIAID Career Transition Award (1K22AI177360-01) Cytokine regulation of recirculating and tissue-resident memory CD8+ T cells in homeostasis and inflammation

Research positions are available at various levels in the Jarjour lab. To apply, please submit a CV, statement of qualifications, and references to Dr. Nicholas Jarjour (njarjour@versiti.org).

Selected Publications

• NN Jarjour, TS Dalzell, NJ Maurice, KM Wanhainen, C Peng, SD O’Flanagan, TA DePauw, KE Block, WJ Valente, KM Ashby, D Masopust, SC Jameson. “Collaboration between interleukin-7 and -15 enables adaptation of tissue-resident and circulating memory CD8+ T cells to cytokine deficiency.” Immunity, 2025;58(3):616-631.
• NN Jarjour, KM Wanhainen, C Peng, NV Gavil, NJ Maurice, H Borges da Silva, RJ Martinez, TS Dalzell, MA Huggins, D Masopust, SE Hamilton, SC Jameson. “Responsiveness to interleukin-15 therapy is shared between tissue-resident and circulating memory CD8+ T cell subsets.” Proc. Natl. Acad. Sci. U.S.A., 2022;119(43):e2209021119.
• NN Jarjour, EA Schwarzkopf, TR Bradstreet, I Shchukina, C-C Lin, SC-C Huang, C-W Lai, ME Cook, R Taneja, TS Stappenbeck, GJ Randolph, MN Artyomov, JF Urban, Jr., BT Edelson. "Bhlhe40 mediates tissue-specific control of macrophage proliferation in homeostasis and type 2 immunity.” Nature Immunology, 2019;20(6):687-700.