scholarly journals Molecular Features Underlying Shp1/Shp2 Discrimination by Immune Checkpoint Receptors

2021 ◽  
Author(s):  
Enfu Hui ◽  
Xiaozheng Xu ◽  
Takeya Masubuchi ◽  
Yunlong Zhao
Keyword(s):  
T Cells ◽  
Immune Checkpoint ◽  
Molecular Basis ◽  
Side Chain ◽  
Sh2 Domains ◽  
Molecular Features ◽  
Molecular Interpretation ◽  
Parallel Mode ◽  
Checkpoint Receptors ◽  
Effector Binding

Numerous inhibitory immunoreceptors operate by recruiting phosphatase effectors Shp1 and Shp2 through conserved motifs ITIM and ITSM. Despite the similarity, these receptors exhibit distinct effector binding specificities, as exemplified by PD-1 and BTLA, which preferentially recruit Shp2 and Shp1 respectively. The molecular basis of Shp1/Shp2 discrimination is unclear. Here, we provide evidence that optimal PD-1 and BTLA binding to both Shp1 and Shp2 occurs via a bivalent, parallel mode that involves both SH2 domains of Shp1/Shp2. Moreover, PD-1 mainly uses its ITSM to discriminate Shp2 from Shp1 via their C-terminal SH2 domains. Supportive of this model, swapping the Shp1-cSH2 with Shp2-cSH2 enabled PD-1:Shp1 association in T cells. In contrast, BTLA primarily utilizes its ITIM to discriminate Shp1 from Shp2 via their N-terminal SH2 domains. Substitution of glycine at pY+1 position of the PD-1-ITIM with alanine, a residue conserved in several Shp1-recruiting receptors, was sufficient to induce PD-1:Shp1 interaction in T cells. Finally, mutagenesis screening shows that Shp1 recruitment exhibits a bell-shaped dependence on the side chain volume of the pY+1 residue of ITIM. Collectively, we provide a molecular interpretation of the Shp1/Shp2-binding specificities of PD-1 and BTLA, with general implications for the mechanism of effector discrimination by inhibitory receptors.

scholarly journals Molecular features underlying differential SHP1/SHP2 binding of immune checkpoint receptors

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Xiaozheng Xu ◽  
Takeya Masubuchi ◽  
Qixu Cai ◽  
Yunlong Zhao ◽  
Enfu Hui
Keyword(s):  
T Cells ◽  
Immune Checkpoint ◽  
Large Family ◽  
Side Chain ◽  
Sh2 Domains ◽  
Molecular Features ◽  
Molecular Interpretation ◽  
Parallel Mode ◽  
Checkpoint Receptors ◽  
Effector Binding

A large number of inhibitory receptors recruit SHP1 and/or SHP2, tandem-SH2-containing phosphatases, through phosphotyrosine-based motifs ITIM and ITSM. Despite the similarity, these receptors exhibit differential effector binding specificities, as exemplified by the immune checkpoint receptors PD-1 and BTLA, which preferentially recruit SHP2 and SHP1 respectively. The molecular basis by which structurally similar receptors discriminate SHP1 and SHP2 is unclear. Here, we provide evidence that human PD-1 and BTLA optimally bind to SHP1 and SHP2 via a bivalent, parallel mode that involves both SH2 domains of SHP1 or SHP2. PD-1 mainly uses its ITSM to prefer SHP2 over SHP1 via their C-terminal SH2 domains (cSH2): swapping SHP1-cSH2 with SHP2-cSH2 enabled PD-1:SHP1 association in T cells. In contrast, BTLA primarily utilizes its ITIM to prefer SHP1 over SHP2 via their N-terminal SH2 domains (nSH2). The ITIM of PD-1, however, appeared to be de-emphasized due to a glycine at pY+1 position. Substitution of this glycine with alanine, a residue conserved in BTLA and several SHP1-recruiting receptors, was sufficient to induce PD-1:SHP1 interaction in T cells. Finally, structural simulation and mutagenesis screening showed that SHP1 recruitment activity exhibits a bell-shaped dependence on the side chain volume of the pY+1 residue of ITIM. Collectively, we provide a molecular interpretation of the SHP1/SHP2-binding specificities of PD-1 and BTLA, with implications for the mechanisms of a large family of therapeutically relevant receptors.

IMMU-06. COMBINATORIAL IMMUNE CHECKPOINT INHIBITORS FOR TARGETED INTRATUMORAL DELIVERY IN GBM

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi93-vi93
Author(s):  
Stephanie Sanders ◽  
Denise Herpai ◽  
Waldemar Debinski
Keyword(s):  
T Cells ◽  
Tumor Cells ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Cell Activity ◽  
Live Cells ◽  
Normal Brain ◽  
Cytotoxic Therapies ◽  
Checkpoint Receptors

Abstract Glioblastoma (GBM) is an immunologically cold tumor. Using single cell sequencing of CD45+ cells we confirmed that T cells are present within GBM samples. These T cells are positive for exhaustion markers such as LAG3 and TIGIT, as well as CTLA4 and PD1 checkpoint receptors. Modulating T cell activity through use of immune checkpoint inhibitors (ICIs) has shown efficacy in the treatment of a variety of solid tumors, and the combination of anti-CTLA4 and anti-PD1 ICIs has shown increased efficacy over use of a single therapeutic. Additionally, targeting ICIs to the tumor cells may increase efficacy of this treatment. We therefore constructed a combinatorial ICI redirected to GBM via interleukin 13 receptor alpha 2 (IL13RA2), a receptor over-expressed on the majority of GBM cells but not normal brain. The first component of the construct, labeled with a histidine tag, targets CTLA4 while the second component, tagged with a StrepII tag, targets PD1. The tags added to the constructs will allow for purification of a combinatorial heterodimer simultaneously targeting PD1, CTLA4 and IL13RA2. We purified individual components via fast protein liquid chromatography (FPLC) using a proteinG column followed by a HisTrap or StrepTrap column. We obtained a recombinant, targeted multivalent ICI at > 95% purity. We found that these constructs are able to bind their target receptors via ELISA in which the Kd values ranged from picomolar to low nanomolar range. Additionally, our constructs bind their target on live cells by flow cytometry. We next designed a heterodimeric construct which can combinatorially target CTLA4 and PD1 while also directing the ICI therapy to GBM. These constructs in conjunction with other immune stimulants like cytotoxic therapies are intended to facilitate the interaction between T cells and GBM tumor cells directly in a tumor microenvironment.

scholarly journals Inhibiting the Unconventionals: Importance of Immune Checkpoint Receptors in γδ T, MAIT, and NKT Cells

Cancers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 4647
Author(s):  
Elisa Catafal-Tardos ◽  
Maria Virginia Baglioni ◽  
Vasileios Bekiaris
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Checkpoint ◽  
Immune Surveillance ◽  
Nkt Cells ◽  
T Cell Subsets ◽  
Cancer Models ◽  
Clinical Responses ◽  
Checkpoint Receptors ◽  
Cancer Immunotherapies

In recent years, checkpoint inhibitor (CPI) therapy has shown promising clinical responses across a broad range of cancers. However, many patients remain unresponsive and there is need for improvement. CPI therapy relies on antibody-mediated neutralization of immune inhibitory or checkpoint receptors (ICRs) that constitutively suppress leukocytes. In this regard, the clinical outcome of CPI therapy has primarily been attributed to modulating classical MHC-restricted αβ T cell responses, yet, it will inevitably target most lymphoid (and many myeloid) populations. As such, unconventional non-MHC-restricted gamma delta (γδ) T, mucosal associated invariant T (MAIT) and natural killer T (NKT) cells express ICRs at steady-state and after activation and may thus be affected by CPI therapies. To which extent, however, remains unclear. These unconventional T cells are polyfunctional innate-like lymphocytes that play a key role in tumor immune surveillance and have a plethora of protective and pathogenic immune responses. The robust anti-tumor potential of γδ T, MAIT, and NKT cells has been established in a variety of preclinical cancer models and in clinical reports. In contrast, recent studies have documented a pro-tumor effect of innate-like T cell subsets that secrete pro-inflammatory cytokines. Consequently, understanding the mechanisms that regulate such T cells and their response to CPI is critical in designing effective cancer immunotherapies that favor anti-tumor immunity. In this Review, we will discuss the current understanding regarding the role of immune checkpoint regulation in γδ T, MAIT, and NKT cells and its importance in anti-cancer immunity.

Abstract 5613: PD-1 and TIGIT are major immune checkpoint receptors expressed in breast cancer-infiltrating T cells

2017 ◽  
Author(s):  
Jee Ye Kim ◽  
Minsuk Kwon ◽  
Sung Mook Lim ◽  
Joo Heung Kim ◽  
Hyung Seok Park ◽  
...  
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Immune Checkpoint ◽  
Checkpoint Receptors

Expression of Immune Checkpoint Receptors on T-Cells and Their Ligands on Leukemia Blasts in Childhood Acute Leukemia

2019 ◽  
Vol 39 (10) ◽  
pp. 5531-5539 ◽  
Author(s):  
SUNG HAN KANG ◽  
HYUN JU HWANG ◽  
JAE WON YOO ◽  
HYERY KIM ◽  
EUN SEOK CHOI ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Leukemia ◽  
Immune Checkpoint ◽  
Childhood Acute Leukemia ◽  
Checkpoint Receptors

scholarly journals Simultaneous, cell-intrinsic downregulation of PD-1 and TIGIT enhances the effector function of CD19-targeting CAR T cells and promotes an early-memory phenotype

2020 ◽  
Author(s):  
Young-Ho Lee ◽  
Hyeong Ji Lee ◽  
Hyung Cheol Kim ◽  
Yujean Lee ◽  
Su Kyung Nam ◽  
...  
Keyword(s):  
T Cells ◽  
B Cell ◽  
Immune Checkpoint ◽  
Therapeutic Option ◽  
B Cell Lymphoma ◽  
Effector Function ◽  
Antitumor Effects ◽  
Car T Cells ◽  
Car T ◽  
Checkpoint Receptors

AbstractCD19-targeting chimeric antigen receptor (CAR) T cells have become an important therapeutic option for patients with relapsed and refractory B cell malignancies. However, recent clinical data indicate that a significant portion of patients still do not benefit from the therapy owing to various resistance mechanisms, including high expression of multiple inhibitory immune checkpoint receptors on activated CAR T cells. Here, we report a lentiviral two-in-one CAR T approach in which two checkpoint receptors are downregulated simultaneously by a dual short-hairpin RNA (shRNA) cassette integrated into a CAR vector. Using this system, we evaluated CD19-targeting CAR T cells in the context of four different checkpoint combinations—PD-1/TIM-3, PD-1/LAG-3, PD-1/CTLA-4 and PD-1/TIGIT—and found that CAR T cells with PD-1/TIGIT downregulation uniquely exerted synergistic antitumor effects in mouse xenograft models compared with PD-1 single downregulation, and maintained cytolytic and proliferative capacity upon repeated antigen exposure. Importantly, functional and phenotypic analyses of CAR T cells as well as analyses of transcriptomic profiles suggested that downregulation of PD-1 enhances short-term effector function, whereas downregulation of TIGIT is primarily responsible for maintaining a less-differentiated/exhausted state, providing a potential mechanism for the observed synergy. The PD-1/TIGIT–downregulated CAR T cells generated from diffuse large B-cell lymphoma patient-derived T cells using a clinically applicable manufacturing process also showed robust antitumor activity and significantly improved persistence in vivo compared with conventional CD19-targeting CAR T cells. Overall, our results demonstrate that the cell-intrinsic PD-1/TIGIT dual downregulation strategy may prove effective in overcoming immune checkpoint-mediated resistance in CAR T therapy.

scholarly journals Enrichment of the HIV reservoir in CD32+ CD4 T cells occurs early in blood and tissue

2017 ◽  
Author(s):  
Genevieve E Martin ◽  
Matthew Pace ◽  
John P Thornhill ◽  
Chansavath Phetsouphanh ◽  
Jodi Meyerowitz ◽  
...  
Keyword(s):  
T Cells ◽  
Antiretroviral Therapy ◽  
Immune Checkpoint ◽  
Cd4 T Cells ◽  
Treatment Interruption ◽  
Healthy Controls ◽  
Hiv Dna ◽  
Hla Dr ◽  
Latently Infected ◽  
Checkpoint Receptors

AbstractThe Fc receptor CD32 has been proposed as a marker for CD4 T cells latently infected with HIV. We demonstrate that enrichment for HIV DNA in CD32+ CD4 T cells can be found early in infection in both tissue and blood. However, we find no evidence for a correlation between CD32 expression on CD4 T cells and either HIV DNA levels or time to rebound viraemia following treatment interruption. CD32+ CD4 T cells have a more differentiated memory phenotype, and high levels of expression of immune checkpoint receptors PD-1, Tim-3 and TIGIT as well as the activation marker, HLA DR. There was no difference in the phenotype or frequency of CD32 expressing cells prior to or after the initiation of antiretroviral therapy, or compared with healthy controls, suggesting that preferential infection or survival, rather than up-regulation, may be responsible for the observed enrichment of proviral HIV DNA in CD32+ CD4 T cells.

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