Unique transcriptional and protein-expression signature in human lung tissue-resident NK cells

Human lung tissue-resident NK cells (trNK cells) are likely to play an important role in host responses towards viral infections, inflammatory conditions and cancer. However, detailed insights into these cells are still largely lacking. Here we show, using RNA sequencing and flow cytometry-based analyses, that subsets of human lung CD69(-)CD16(-) NK cells display hallmarks of tissue-residency, including high expression of CD49a, CD103, and ZNF683, and reduced expression of SELL, S1PR5, and KLF2/3. CD49a(+)CD16(-) NK cells are functionally competent, and produce IFN-gamma, TNF, MIP-1 beta, and GM-CSF. After stimulation with IL-15, they upregulate perforin, granzyme B, and Ki67 to a similar degree as CD49a(-) CD16(-) NK cells. Comparing datasets from trNK cells in human lung and bone marrow with tissue-resident memory CD8(+) T cells identifies core genes co-regulated either by tissue-residency, cell-type or location. Together, our data indicate that human lung trNK cells have distinct features, likely regulating their function in barrier immunity.Peer reviewe

T-bet and Eomes Are Differentially Linked to the Exhausted Phenotype of CD8+T Cells in HIV Infection

CD8+ T cell exhaustion represents a major hallmark of chronic HIV infection. Two key transcription factors governing CD8+ T cell differentiation, T-bet and Eomesodermin (Eomes), have previously been shown in mice to differentially regulate T cell exhaustion in part through direct modulation of PD-1. Here, we examined the relationship between these transcription factors and the expression of several inhibitory receptors (PD-1, CD160, and 2B4), functional characteristics and memory differentiation of CD8+ T cells in chronic and treated HIV infection. The expression of PD-1, CD160, and 2B4 on total CD8+ T cells was elevated in chronically infected individuals and highly associated with a T-betdimEomeshi expressional profile. Interestingly, both resting and activated HIV-specific CD8+ T cells in chronic infection were almost exclusively T-betdimEomeshi cells, while CMV-specific CD8+ T cells displayed a balanced expression pattern of T-bet and Eomes. The T-betdimEomeshi virus-specific CD8+ T cells did not show features of terminal differentiation, but rather a transitional memory phenotype with poor polyfunctional (effector) characteristics. The transitional and exhausted phenotype of HIV-specific CD8+ T cells was longitudinally related to persistent Eomes expression after antiretroviral therapy (ART) initiation. Strikingly, these characteristics remained stable up to 10 years after ART initiation. This study supports the concept that poor human viral-specific CD8+ T cell functionality is due to an inverse expression balance between T-bet and Eomes, which is not reversed despite long-term viral control through ART. These results aid to explain the inability of HIV-specific CD8+ T cells to control the viral replication post-ART cessation

CD49a Expression Defines Tissue-Resident CD8+ T Cells Poised for Cytotoxic Function in Human Skin

Tissue-resident memory T (Trm) cells form a heterogeneous population that provides localized protection against pathogens. Here, we identify CD49a as a marker that differentiates CD8(+) Trm cells on a compartmental and functional basis. In human skin epithelia, CD8(+)CD49a(+) Trm cells produced interferon-γ, whereas CD8(+)CD49a(−) Trm cells produced interleukin-17 (IL-17). In addition, CD8(+)CD49a(+) Trm cells from healthy skin rapidly induced the expression of the effector molecules perforin and granzyme B when stimulated with IL-15, thereby promoting a strong cytotoxic response. In skin from patients with vitiligo, where melanocytes are eradicated locally, CD8(+)CD49a(+) Trm cells that constitutively expressed perforin and granzyme B accumulated both in the epidermis and dermis. Conversely, CD8(+)CD49a(–) Trm cells from psoriasis lesions predominantly generated IL-17 responses that promote local inflammation in this skin disease. Overall, CD49a expression delineates CD8(+) Trm cell specialization in human epithelial barriers and correlates with the effector cell balance found in distinct inflammatory skin diseases

Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19

SARS-CoV-2-specific memory T cells will likely prove critical for long-term immune protection against COVID-19. Here, we systematically mapped the functional and phenotypic landscape of SARS-CoV-2-specific T cell responses in unexposed individuals, exposed family members, and individuals with acute or convalescent COVID-19. Acute-phase SARS-CoV-2-specific T cells displayed a highly activated cytotoxic phenotype that correlated with various clinical markers of disease severity, whereas convalescent-phase SARS-CoV-2-specific T cells were polyfunctional and displayed a stem-like memory phenotype. Importantly, SARS-CoV-2-specific T cells were detectable in antibody-seronegative exposed family members and convalescent individuals with a history of asymptomatic and mild COVID-19. Our collective dataset shows that SARS-CoV-2 elicits broadly directed and functionally replete memory T cell responses, suggesting that natural exposure or infection may prevent recurrent episodes of severe COVID-19

Adjusted dose-response association between daily calcium supplement intake and risk for cardiovascular death.

<p>Calcium supplement intake was coded using an RCS function with four knots arbitrarily located at the 0.05, 0.35, 0.65, and 0.95 percentile. Y-axis represents the adjusted hazard ratio for cardiovascular death for any value of calcium supplement/dietary intake compared to individuals with 0 mg per day intake. Dashed lines are 95% confidence intervals. Knots are represented by dots.</p

Baseline characteristics of study population by vital status.

<p>Baseline characteristics of study population by vital status.</p

Hazard Ratios and 95%Confidence Intervals for risk of cardiovascular death by serum, dietary, supplement, and total calcium.

1<p>Adjusted for: age, sex, race/ethnicity, poverty to income ratio, comorbidity index, serum vitamin D, alcohol consumption, smoking behaviour, vigorous physical activity, and BMI.</p>2<p>Adjusted for: age, sex, race/ethnicity, poverty to income ratio, comorbidity index, serum vitamin D, alcohol consumption, smoking behaviour, vigorous physical activity, total energy intake, and BMI.</p

Adjusted dose-response association between daily dietary calcium intake and risk for cardiovascular death.

<p>Calcium intake was coded using an RCS function with four knots arbitrarily located at the 0.05, 0.35, 0.65, and 0.95 percentile. Y-axis represents the adjusted hazard ratio for cardiovascular death for any value of calcium supplement/dietary intake compared to individuals with 1000 mg per day intake. Dashed lines are 95% confidence intervals. Knots are represented by dots.</p

Expansions of adaptive-like NK cells with a tissue-resident phenotype in human lung and blood

Human adaptive-like "memory" CD56(dim)CD16(+) natural killer (NK) cells in peripheral blood from cytomegalovirus-seropositive individuals have been extensively investigated in recent years and are currently explored as a treatment strategy for hematological cancers. However, treatment of solid tumors remains limited due to insufficient NK cell tumor infiltration, and it is unknown whether large expansions of adaptive-like NK cells that are equipped for tissue residency and tumor homing exist in peripheral tissues. Here, we show that human lung and blood contains adaptive-like CD56(bright)CD16(-) NK cells with hallmarks of tissue residency, including expression of CD49a. Expansions of adaptive-like lung tissue-resident NK (trNK) cells were found to be present independently of adaptive-like CD56(dim)CD16(+) NK cells and to be hyperresponsive toward target cells. Together, our data demonstrate that phenotypically, functionally, and developmentally distinct subsets of adaptive-like NK cells exist in human lung and blood. Given their tissue-related character and hyperresponsiveness, human lung adaptive-like trNK cells might represent a suitable alternative for therapies targeting solid tumors.Peer reviewe

Influenza A Virus Infection Induces Hyperresponsiveness in Human Lung Tissue-Resident and Peripheral Blood NK Cells

NK cells in the human lung respond to influenza A virus-(IAV-) infected target cells. However, the detailed functional capacity of human lung and peripheral blood NK cells remains to be determined in IAV and other respiratory viral infections. Here, we investigated the effects of IAV infection on human lung and peripheral blood NK cells in vitro and ex vivo following clinical infection. IAV infection of lung- and peripheral blood-derived mononuclear cells in vitro induced NK cell hyperresponsiveness to K562 target cells, including increased degranulation and cytokine production particularly in the CD56(bright)CD16(-) subset of NK cells. Furthermore, lung CD16(-) NK cells showed increased IAV-mediated but target cell-independent activation compared to CD16(+) lung NK cells or total NK cells in peripheral blood. IAV infection rendered peripheral blood NK cells responsive toward the normally NK cell-resistant lung epithelial cell line A549, indicating that NK cell activation during IAV infection could contribute to killing of surrounding non-infected epithelial cells. In vivo, peripheral blood CD56(dim)CD16(+) and CD56(bright)CD16(-) NK cells were primed during acute IAV infection, and a small subset of CD16(-) CD49a(+)CXCR3(+) NK cells could be identified, with CD49a and CXCR3 potentially promoting homing to and tissue-retention in the lung during acute infection. Together, we show that IAV respiratory viral infections prime otherwise hyporesponsive lung NK cells, indicating that both CD16(+) and CD16(-) NK cells including CD16(-)CD49a(+) tissue-resident NK cells could contribute to host immunity but possibly also tissue damage in clinical IAV infection.Peer reviewe