Pre-clinical validation of a pan-cancer CAR-T cell immunotherapy targeting nfP2X7.

Chimeric antigen receptor (CAR)-T cell immunotherapy is a novel treatment that genetically modifies the patients' own T cells to target and kill malignant cells. However, identification of tumour-specific antigens expressed on multiple solid cancer types, remains a major challenge. P2X purinoceptor 7 (P2X7) is a cell surface expressed ATP gated cation channel, and a dysfunctional version of P2X7, named nfP2X7, has been identified on cancer cells from multiple tissues, while being undetectable on healthy cells. We present a prototype -human CAR-T construct targeting nfP2X7 showing potential antigen-specific cytotoxicity against twelve solid cancer types (breast, prostate, lung, colorectal, brain and skin). In xenograft mouse models of breast and prostate cancer, CAR-T cells targeting nfP2X7 exhibit robust anti-tumour efficacy. These data indicate that nfP2X7 is a suitable immunotherapy target because of its broad expression on human tumours. CAR-T cells targeting nfP2X7 have potential as a wide-spectrum cancer immunotherapy for solid tumours in humans.

Determination of Tr1 cell populations correlating with distinct activation states in acute IAV infection.

Type I regulatory (Tr1) cells are defined as FOXP3-IL-10-secreting clusters of differentiation (CD4+) T cells that contribute to immune suppression and typically express the markers LAG-3 and CD49b and other co-inhibitory receptors. These cells have not been studied in detail in the context of the resolution of acute infection in the lung. Here, we identify FOXP3- interleukin (IL)-10+ CD4+ T cells transiently accumulating in the lung parenchyma during resolution of the response to sublethal influenza A virus (IAV) infection in mice. These cells were dependent on IL-27Rα, which was required for timely recovery from IAV-induced weight loss. LAG-3 and CD49b were not generally co-expressed by FOXP3- IL-10+ CD4+ T cells in this model and four populations of these cells based on LAG-3 and CD49b co-expression were apparent [LAG-3-CD49b- (double negative), LAG-3+CD49b+ (double positive), LAG-3+CD49b- (LAG-3+), LAG-3-CD49b+ (CD49b+)]. However, each population exhibited suppressive potential consistent with the definition of Tr1 cells. Notably, differences between these populations of Tr1 cells were apparent including differential dependence on IL-10 to mediate suppression and expression of markers indicative of different activation states and terminal differentiation. Sort-transfer experiments indicated that LAG-3+ Tr1 cells exhibited the capacity to convert to double negative and double positive Tr1 cells, indicative of plasticity between these populations. Together, these data determine the features and suppressive potential of Tr1 cells in the resolution of IAV infection and identify four populations delineated by LAG-3 and CD49b, which likely correspond to different Tr1 cell activation states.

A systems immunology study comparing innate and adaptive immune responses in adults to COVID-19 mRNA and adenovirus vectored vaccines.

Identifying the molecular mechanisms that promote optimal immune responses to coronavirus disease 2019 (COVID-19) vaccination is critical for future rational vaccine design. Here, we longitudinally profile innate and adaptive immune responses in 102 adults after the first, second, and third doses of mRNA or adenovirus-vectored COVID-19 vaccines. Using a multi-omics approach, we identify key differences in the immune responses induced by ChAdOx1-S and BNT162b2 that correlate with antigen-specific antibody and T cell responses or vaccine reactogenicity. Unexpectedly, we observe that vaccination with ChAdOx1-S, but not BNT162b2, induces an adenoviral vector-specific memory response after the first dose, which correlates with the expression of proteins with roles in thrombosis with potential implications for thrombosis with thrombocytopenia syndrome (TTS), a rare but serious adverse event linked to adenovirus-vectored vaccines. The COVID-19 Vaccine Immune Responses Study thus represents a major resource that can be used to understand the immunogenicity and reactogenicity of these COVID-19 vaccines.

CXCR5+CD8+ T Cells Shape Antibody Responses In Vivo Following Protein Immunisation and Peripheral Viral Infection.

Crosstalk between T and B cells is crucial for generating high-affinity, class-switched antibody responses. The roles of CD4+ T cells in this process have been well-characterised. In contrast, regulation of antibody responses by CD8+ T cells is significantly less defined. CD8+ T cells are principally recognised for eliciting cytotoxic responses in peripheral tissues and forming protective memory. However, recent findings have identified a novel population of effector CD8+ T cells that co-opt a differentiation program characteristic of CD4+ T follicular helper (Tfh) cells, upregulate the chemokine receptor CXCR5 and localise to B cell follicles. While it has been shown that CXCR5+CD8+ T cells mediate the removal of viral reservoirs in the context of follicular-trophic viral infections and maintain the response to chronic insults by virtue of progenitor/stem-like properties, it is not known if CXCR5+CD8+ T cells arise during acute peripheral challenges in the absence of follicular infection and whether they influence B cell responses in vivo in these settings. Using the ovalbumin-specific T cell receptor transgenic (OT-I) system in an adoptive transfer-immunisation/infection model, this study demonstrates that CXCR5+CD8+ T cells arise in response to protein immunisation and peripheral viral infection, displaying a follicular-homing phenotype, expression of cell surface molecules associated with Tfh cells and limited cytotoxic potential. Furthermore, studies assessing the B cell response in the presence of OT-I or Cxcr5-/- OT-I cells revealed that CXCR5+CD8+ T cells shape the antibody response to protein immunisation and peripheral viral infection, promoting class switching to IgG2c in responding B cells. Overall, the results highlight a novel contribution of CD8+ T cells to antibody responses, expanding the functionality of the adaptive immune system.

Atypical chemokine receptor 4 shapes activated B cell fate.

Activated B cells can initially differentiate into three functionally distinct fates-early plasmablasts (PBs), germinal center (GC) B cells, or early memory B cells-by mechanisms that remain poorly understood. Here, we identify atypical chemokine receptor 4 (ACKR4), a decoy receptor that binds and degrades CCR7 ligands CCL19/CCL21, as a regulator of early activated B cell differentiation. By restricting initial access to splenic interfollicular zones (IFZs), ACKR4 limits the early proliferation of activated B cells, reducing the numbers available for subsequent differentiation. Consequently, ACKR4 deficiency enhanced early PB and GC B cell responses in a CCL19/CCL21-dependent and B cell-intrinsic manner. Conversely, aberrant localization of ACKR4-deficient activated B cells to the IFZ was associated with their preferential commitment to the early PB linage. Our results reveal a regulatory mechanism of B cell trafficking via an atypical chemokine receptor that shapes activated B cell fate.