CD8+ T–NK cell crosstalk establishes preemptive immunosurveillance to eliminate antigen–escape tumors

Background and objectiveTumor antigen–escape variants undermine immunotherapy by subverting lymphocyte effector functions and reshaping tumor–immune dynamics. It is essential to delineate functional interplay within immune networks during tumor progression. We investigated whether homeostatic crosstalk between CD8+T cells and natural killer (NK) cells preempts tumor antigen–escape. MethodsAdoptive CD8+T cell transfers were administered before (D–7, homeostatic pre-priming) or after (D+1) tumor establishment in Rag1−/− and Rag1−/−γc−/− mice. Antigen presentation, immune activation, proliferation, cytotoxicity, and memory were quantified by flow cytometry, live bioluminescence and confocal imaging. Monoculture, co-culture, and a 3D silica nanofiber carpet mimicking basement-membrane-like topography modeled intercellular interactions. Signaling arrays and motion metrics (Speed-Distance Index, deceleration) were conducted. Human ligand–receptor pairs engaged in CD8+T–NK crosstalk were probed in silico.Results and discussionPre-tumor D–7 CD8+T cell transfer completely suppressed antigen–escape tumors with NK cells as major effectors showing elevated CD25, CD69, CD107a, and GzmB, marking activated and effector phenotype, and promoting central-memory CD62L⁺CD44⁺CD8⁺TCM precursors. By contrast, post-tumor D+1–transferred CD8+T cells allowed emergence of tumor variants resistant to antigen-specific cytolysis as assessed on day 25, despite those T cells retaining higher intrinsic cytotoxic capacity than the D–7 T cell cohort. Mechanistically, CD8+T and NK cells formed stable contacts through pseudopodial intercellular nanotubes enabling bidirectional membrane exchange and signaling via STAT, Akt, and mTOR pathways, augmenting NK effector function and promoting CD8+TCM differentiation. In silico analysis identified human ligand–receptor pairs engaged in CD8+T–NK adhesion, stimulatory and regulatory axes, including CD200–CD200R, PD-L1–PD-1, and CD18/CD11a–DNAM-1 (CD226). Together, data support a three-phase model of preemptive immunosurveillance initiated by early CD8⁺T–NK crosstalk.ConclusionHomeostatic conditioning and effector cooperativity between CD8+T and NK cells protect against tumor immune escape. The findings uncover a mechanistic axis of preemptive immunosurveillance that lays the foundation for next-generation preventive immunotherapies to control antigen–escape tumors

Disrupted lymph node and splenic stroma in mice with induced inflammatory melanomas is associated with impaired recruitment of T and dendritic cells

International audienceMigration of dendritic cells (DC) from the tumor environment to the T cell cortex in tumor-draining lymph nodes (TDLN) is essential for priming naïve T lymphocytes (TL) to tumor antigen (Ag). We used a mouse model of induced melanoma in which similar oncogenic events generate two phenotypically distinct melanomas to study the influence of tumor-associated inflammation on secondary lymphoid organ (SLO) organization. One tumor promotes inflammatory cytokines, leading to mobilization of immature myeloid cells (iMC) to the tumor and SLO; the other does not. We report that inflammatory tumors induced alterations of the stromal cell network of SLO, profoundly altering the distribution of TL and the capacity of skin-derived DC and TL to migrate or home to TDLN. These defects, which did not require tumor invasion, correlated with loss of fibroblastic reticular cells in T cell zones and in impaired production of CCL21. Infiltrating iMC accumulated in the TDLN medulla and the splenic red pulp. We propose that impaired function of the stromal cell network during chronic inflammation induced by some tumors renders spleens non-receptive to TL and TDLN non-receptive to TL and migratory DC, while the entry of iMC into these perturbed SLO is enhanced. This could constitute a mechanism by which inflammatory tumors escape immune control. If our results apply to inflammatory tumors in general, the demonstration that SLO are poorly receptive to CCR7-dependent migration of skin-derived DC and naïve TL may constitute an obstacle for proposed vaccination or adoptive TL therapies of their hosts

Phénoménologie de l'échappement tumoral dans un modèle murin de mélanome indictible

L'impact du système immunitaire dans la progression tumorale est controversé. dans les modèles de tumerus transplantées, ou spontanées exprimant des antigènes viraux, la réponse immunitaire anti-tumorale a été décrite comme soit diminuant soit favorisant la croissance tumorale. Nous avons évalué l'impact du système immunitaire sur deux tyes distincts de mélanomes induits chez la souris par la délétion conditionnelle de gènes suppresseurs de tumeur, l'exression concomitante d'un oncogène et d'un antigène tumoral. Le mélanome à croissance lente semble être "ignoré" par le système immunitaire. Alors que le mélanome "agressif" est infiltré par des cellules myéloïdes immatures et par des lymphocytes T présentant un phénotype "épuisé", en association avec une inflammation chronique systémique de type Th2. Contrairement aux autres modèles de tumeurs spontanées, le déclenchement de l'inflammation est ici indépendant de l'immunité adaptative, qui au contraire, retarde le développement tumoral, mais est supplanté par l'inflammation. Chez ces souris, des troubles dans l'hématopoïèse et un recrutement de cellules myéloïdes au niveau des organes lymphoïdes sont associés à une immunosuppression etravant la thérapie cellulaire par transfert adoptif. De façon intéressante, l'expression de gènes définissant la transition épithélio-mésenchymateuse, ainsi que des gènes codant pour des chémiokines et de cytokines immuno-modulatrices caractérisent la mélanome agressif comparé au mélanome non agressif, établissant ainsi un lien entre le processus de la transition épithélio-mésenchymateuse et des altérations des fonctions immunitairesThe role of the immune system in tumor progression is controversial. In studies of mouse transplanted tumors or spontaneous tumors expressing viral antigens, anti-tumor immune reactivity was found either to restrict or promote growth. We evaluated the impact of the immune system on two differencially aggressive melanomas developing in mice upon conditional deletion of the same tumor suppressor genes and concomitant expression of oncogene H-RasG12V and a natural cancer-germline tumor antigene. "Slow progressor" melanomas appeared to be "ignored" by the immune system. "Agressive" melanomas were infiltrated by immature myeloid cells and by T lymphocytes presenting an "exhausted" phenotype, in association with local inflammation and systemic Th2 dominant chronic inflammation. In constrast to other models, initiation of inflammation was here independent of adaptative immunity, which delayed the development of agressive melanomas, but was overridden by inflammation. In these mice, disorders in hematopoiesis and recuitment of myeloid cells to lymphoid organs were associated with immunosuppression and hampered adoptive T cell therapy. Expression of genes akin to those defining epithelial-mesenchymal transition as well as genes encoding chemokines and immuno-modulating cytokines characterized aggressive compared to slow progressor melomas, thus establishing a link between epithelial-mesenchymal transition-like processes and alterations of immune functions.AIX-MARSEILLE2-BU Sci.Luminy (130552106) / SudocSudocFranceF

Effects of Sodium Periodate Modification of Lymphocytes on the Sensitization and Lytic Phases of T Cell-Mediated Lympholysis

Abstract Sensitization of mouse splenic lymphocytes in vitro with sodium periodate-treated autologous spleen cells stimulated a one-way mixed lymphocyte reaction and led to the generation of thymus-derived cytotoxic effector cells. These effectors were capable of lysing in 4 hr periodate-treated syngeneic and, to a lesser extent, periodate-treated allogeneic target cells. These results suggest that sensitization by periodate-treated autologous cells could result either from a specific reaction to modified self components or from a nonspecific mitogenic stimulation. Effector cells generated by allogeneic sensitization were detected on periodate-modified targets, irrespective of the H-2 antigens expressed by the targets. The effects of periodate modification on both stimulator and target cells were reversible by sodium borohydride, suggesting that the biologic effects of sodium periodate are dependent on the formation of a free aldehyde group on cell surface glycoproteins. Pretreatment of stimulator cells with neuroaminidase prevented the effect of periodate treatment, suggesting that the sensitization involves oxidized sialic acid residues. During the 4-hour 51Cr-release assay periodate-treated targets could be used to detect cytotoxic effector cells of any specificity. Fresh spleen cells and lymphocytes cultured for 5 days without antigen or in the presence of lipopolysaccharide did not lyse periodate-treated targets. An increasing level of cytotoxicity was detected on periodate-treated targets when the effector cells were generated, respectively, by stimulation with concanavalin A, by sensitization with periodate-modified autologous cells, or by sensitization with unmodified allogeneic stimulator cells. Although the lysis of periodate-treated targets is itself nonspecific, effector cell specificity could be determined by selective blocking of the lytic phase with cells syngeneic to the stimulators. These results indicate that a nonspecific interaction can occur between lymphocytes and periodate-treated target cells, but that this interaction leads to lysis only when the lymphocytes were activated to become cytotoxic effectors.</jats:p

F1 Resistance to AKR Lymphoma Cells in Vivo and in Vitro

Abstract AKR × DBA/2 (AKD2F1) mice resist growth of injected spontaneous AKR lymphoma cells. In vitro, normal F1 responder cells generate Thy-1 positive effector cells specifically cytotoxic for the sensitizing antigens of parental AKR normal or lymphoma cells. The possibility is considered that the homozygous normal and neoplastic AKR cells express antigenic determinants, analogous to hemopoietic histocompatibility (Hh) antigens, which are recognized by the F1 hybrid, resulting in in vivo tumor resistance and in vitro cell-mediated cytotoxicity.</jats:p

Specific Helper T Cells Permit Differentiation of Thymic Anti-Self-Trinitrophenyl Cytotoxic Precursor Cells

Abstract Thymocytes, in contrast to peripheral T cells, were unable to generate significant numbers of anti-self-TNBS cytotoxic T cells in primary in vitro cultures. The addition to such cultures of syngeneic 1000 rad irradiated lymph node or spleen cells from mice sensitized 6 or 7 days previously with trinitrochlorobenzene (TNCB) permitted the development of an anti-self-TNBS cytotoxic T cell response. This effect was shown to be T-dependent since it was largely abolished by anti-Thy 1 plus complement and was present in nylon-wool column purified T cells. The lymph node cells act as specific helper cells in that a) they must be restimulated in vitro by the priming antigen and b) they do not take part in the lytic phase of the response. The specificity of the helper effect is further indicated a) by the lack of help from nonsensitized lymph node cells and b) by absence of an enhanced helper effect for thymic anti-allogeneic or anti-allogeneic-TNBS responses in the presence of specific T helper cells for the anti-self-TNBS response. Analysis of the thymocyte subpopulation able to provide precursor cells was approached by separating thymocytes into a “medullary-like” minor, peanut-lectin-agglutinable (PNA-) fraction and a “cortical-like” major, peanut-lectin-agglutinable (PNA+) fraction. It was found that the PNA- fraction was enriched in thymocytes able to mount an autonomous anti-self-TNBS cytotoxic response, whereas the PNA+ population was totally unable to generate anti-self-TNBS effector cells in the absence of helper cells. The presence of helper cells from TNCB-painted mice permitted differentiation of anti-self-TNBS cytotoxic precursor cells from the PNA+ thymocyte cultures and enhanced the level of cytotoxic cells generated in PNA- thymocyte cultures.</jats:p