Chimeric antigen receptor (CAR) myeloid cells are a promising potential alternative to CAR T-cells for solid tumor therapies. Myeloid CAR therapies have been tested in preclinical studies by either transferring established CD3-based T-cell CARs into myeloid cells, or by designing myeloid-specific signaling domains. While ITAM-based myeloid receptors (e.g., Fc-receptors) were often outperformed by classic CD3x-designs, toll-interleukin-1 receptor (TIR) and Mer receptor tyrosine kinase (MerTK) have shown promise for improving myeloid-specific cell activation. Addition of CD147 to stimulate the production of matrix- metalloproteinase and of cytokine genes (e.g. interferon g) may further improve the efficacy of CAR-myeloid cells in the tumor immune microenvironment. While most work focused on CAR monocytes and macrophages, CAR-DC cells are also being studied as tumor vaccines in preclinical and early clinical phases. Lastly, even though CAR neutrophils are disadvantaged by a short lifespan, they could become viable by transfusing them as undifferentiated myeloid progenitors instead of effector cells. Here, we summarize the status of preclinical and clinical research on different CAR myeloid strategies, compare receptor designs, outline gaps in knowledge, conflicting results, and approaches for future preclinical studies that will allow translation of these technologies to the clinic.

• Chimeric antigen receptor (CAR)
• CAR Myeloid cells
• Monocyte/Macrophage
• Neutrophil
• Dendritic cell

Buys W, Zambidis ET (2024) Designing Chimeric Antigen Receptors for Myeloid Immune Cells. J Cancer Biol Res 11(1): 1144.

Over the last decade, immune therapies have been firmly established as a fourth pillar of cancer therapy, along with surgery, chemo-, and radiotherapy. Other than modifying host- immunity (e.g., through checkpoint inhibition), this new wave was largely due to the success of chimeric antigen receptor (CAR) T-cells. These lymphoid immune cells [1] are equipped with an artificial receptor construct expressing an antigen-binding domain (e.g., an established antibody against a cancer antigen), a hinge and transmembrane domain, and an intracellular signaling or stimulatory domain. In many iterations, the latter is combined with co-stimulatory domains (Figure 1). Surprisingly, this amalgam of different proteins activates downstream signaling cascades following binding to its target sequence, and elicits anti-tumor T-cell responses with clonal amplification, paracrine signaling, and possibly memory cell formation; thus reducing the tumor burden and potentially eradicating the tumor. Although off-target immune reactions are relevant concerns, the high specificity of antibody-antigen binding results in less misdirected toxicity, than traditional cancer therapies [2]. However, although CAR T-cells have demonstrated great efficacy with liquid malignancies, their potency against solid tumors is limited. This has been attributed to insufficient infiltration and immune- suppression of T-cells in the tumor micro-environment, thus rendering CAR T-cells ineffective at reaching and fulfilling their goal.

Figure 1 Evolution of CAR design.

The design of tumor-infiltrating myeloid immune cells with chimeric antigen receptors has offered an alternative approach to CAR T-cells. However, myeloid immune cells (i.e., macrophages, monocytes, granulocytes, and dendritic cells), have many disadvantages over T-cells. Most importantly, they are unable to clonally amplify upon encountering a target antigen, have a relatively short lifespan, and lack memory cell formation. Thus, they likely require greater cell numbers and multiple therapy courses for a long-term effect [3]. However, myeloid CAR cells also come with a range of key advantages over lymphoid, i.e., T-cell based therapies. Besides biocide production and apoptosis signaling, most myeloid immune cells are not only expert phagocytes, but also at least apt at antigen presentation and paracrine immune signaling, shaping the local immune microenvironment, and priming other immune cells against the target. In addition, myeloid immune cells are highly capable of transgressing physiological barriers (e.g., the blood-brain barrier [4]) and moving through tissue (e.g., across the tumor matrix). Myeloid immune cells weaponized by introducing CAR could thus home to the tumor with high efficiency and rebalance the immune suppressive microenvironment [5,6] to permit the host’s own immune cells (e.g., T-cells) to attack and eventually eradicate the tumor. Because the lymphoid cells in this one-two punch are the host’s own and not monoclonal, the tumor patient may form a multitude of T-cell clones with varying specificity and target sequences, making tumor antigen escape less likely; particularly when CAR-based myeloid targeting is combined with overexpression of T-cell priming and expanding immune mediators, like interleukin 12 and interferon γ [6-8].

Following this promise, CAR myeloid cells with various designs have been explored in preclinical studies (Tables 1,2), and are now entering early clinical phases (Table 3). This review focuses on myeloid-specific considerations for CAR design, and also provides an overview of the prospective myeloid cell sources for this goal.

Stimulatory Domains

When designing chimeric antigen receptors for myeloid cells, the antigen-binding, hinge and transmembrane domains will likely require only minor cell type-specific optimization (e.g., to the length of the hinge-domain [9]). However, it stands to question whether the T-cell specific intracellular signaling domain CD3ζ, and its optional costimulatory domains (e.g., CD28, 4-1BB, OX40), will provide optimal stimulation of myeloid immune cell activity. The lymphoid and myeloid branch of hematopoiesis diverge very early in blood-cell ontogeny (one step downstream of the hematopoietic stem cell) and accordingly develop multiple mutually specific intracellular signaling pathways, begetting their different and highly specialized functions. What’s more, CAR expression and thus therapeutic efficacy can be dependent on differences in receptor subunits [9-11].

On the other hand, the transfer of T-cell CAR designs into a new cell type would leverage 30 years of CAR optimization experience, without the need for developing entirely new receptors; which could save valuable time and resources towards clinical translation. While the CD3 receptor is T-cell specific, it shares the critical immunoreceptor tyrosine-based activation motif (ITAM) domains with many myeloid-specific receptors, like Fcγ (CD32, CD64) and Fcε. ITAM-domains are the primary locus of phosphorylation and thus signal transduction in all these immune receptors and can thus trigger the same downstream- signaling pathways. Accordingly, multiple preclinical studies have demonstrated effectiveness of CD3-based CAR myeloid cells in vitro and in animal models (Table 1). In addition, two out of three ongoing clinical trials that disclosed their CAR designs use a first-generation T-cell CAR design (Table 3, also see Figure 1) reliant on CD3. In direct comparison, other ITAM-associated myeloid-specific receptor domains, like of the Fc-receptors and MegF10, were consistently outperformed by CD3ζ-based designs (Table 2). This has been attributed to the 3 double ITAM domains in CD3ζ [4], whereas Fcγ-receptors and MegF10 comprise 1 and Fcε-receptors 2 ITAM domains, and may thus simply relay less signal per activated receptor.

Table 1: CD3ζ CAR designs in preclinical studies

Table 2: Myeloid-specific CAR designs in preclinical studies

Table 3: Myeloid CAR in clinical studies

For non-ITAM-associated myeloid-specific receptors, MerTK and Toll-interleukin-1 receptor domains have been directly compared to CD3-designs. MerTK, a canonical phagocytosis receptor, is part of the TAM-receptor class and has demonstrated a significant advantage over CD3-designs in one study [12]. Interestingly, this MerTK-CAR was effective in vivo despite not upregulating biocide (nitric oxide) production after activation. It will thus ultimately be interesting, which myeloid CAR design triggers which of the manifold myeloid cell immune responses, and how that contributes to combat the tumor. The aforementioned study also compared Toll-interleukin-1 receptor(TIR)-based CAR to CD3-based designs. TIR is an inflammatory immune receptor family central to septic inflammation [13]. While the main signaling pathway converges with ITAM-signaling in NFκB activation, multiple Toll-like receptors (TLR), especially those located inside the endosome (TLR3, 7/8, 9, 4-late), also signal independent of MyD88-to-NFκB via TRAM and TRIF towards the interferon-responsive-factor pathway, and could thus provide additional effects. In accessory, albeit not in key metrics (such as mouse survival or in vivo tumor size), TLR-based designs have demonstrated advantages over CD3-based CAR. Another study has suggested similar effectiveness of TIR- and CD3-based CAR [14], but unclear labeling complicates interpretation. These cases represent a larger issue with most currently available data on myeloid specific CAR designs: Most reports did not compare their novel designs against a classic CD3-based receptor or only did so in accessory metrics (e.g., cytokine production during co- incubation). However, given the underwhelming performance of other myeloid-specific receptors (e.g., Fc, MegF10), as well as the larger economic consideration of being able to “recycle” T-cell CAR designs for myeloid therapies, future preclinical studies should strive to not only include a negative but also a CD3-CAR positive control in key metrics, such as animal survival or tumor size.

Co-stimulation and Alternative Signaling

In T-cells, the inclusion of single co-stimulatory domains (e.g., CD28, 4-1BB; i.e., 2nd generation) in CAR designs has majorly increased CAR-dependent activation and helped bring CAR T-cells to the clinic. All six FDA-approved CAR-designs [15] carry a CD3 intracellular domain combined with either CD28 or 4-1BB co-stimulatory domains. Accordingly, multiple preclinical studies on myeloid CAR have also included T-cell co-stimulatory domains. Notably, even in unmodified myeloid cells, many of these canonical ‘T-cell costimulatory receptors’ are already expressed and can contribute to cell activation [16]. While data directly comparing first- versus second- / third- generation CD3 CAR-designs in myeloid cells is too sparse for a definite judgement, caution is warranted as at least one study found decreased phagocytosis when adding 4-1BB to CD3- CD147 CAR macrophages [17]. While there’s not yet much data on strictly fourth-generation CAR, at least one study suggests an advantage of co-transfecting interferon γ under a constitutively active promoter to ensure CAR macrophage M1 priming and to counteract therapeutic cells assuming a tumor-associated macrophage phenotype [8].

An interesting case beyond stimulating a more or less generic cellular immune response via ITAM, TIR, or TAM plus co-receptors is the inclusion of CD147 in the intracellular domain. Signaling through CD147, also known as inducer of extracellular matrix metalloproteinase, leads to the digestion of the tumor matrix, thus conceptually enhancing the influx and transmigration of host immune cells into dense tumor tissue; whereas the influence of CD147 on phagocytosis, biocide, or cytokine production is less clear. CD147-CAR has been demonstrated effective in one preclinical study (combined with CD3; [17]) and is being studied in human even without an additional intracellular signaling domain (NCT06224738).

Cell Types and Other Considerations

Preclinical data on CAR has been gathered for all major myeloid immune cell types, namely macrophages/monocytes, neutrophils, and dendritic cells, and is being studied clinically for various mixed myeloid populations, dendritic cells, monocytes, and macrophages. Conceptually, each of these cell types presents certain advantages. While neutrophils are probably most apt at homing beyond physiological barriers, direct cell killing, and biocide production, their short lifespan complicates clinical translation, as even infusing CAR neutrophils weekly, permanent tumor control is yet to be demonstrated in vivo [4]. Of note, activated neutrophils can also potentially promote metastasis, and should thus be approached with special care [18].

While the issue of providing sufficient cell numbers is most relevant to short-lived neutrophils, it is also worth considering for other myeloid cell types. An effect of a single therapy infusion over at least several weeks is not only desired for logistical reasons, but also to allow antigen-presenting cells (APC) to induce a lymphoid immune reaction. However, both the issues of cell numbers as well as persistence can likely be circumvented by transfusing CAR myeloid progenitors, instead of effector cells, as we have reviewed separately [3].

Other than neutrophils, dendritic cells (DC) are not canonically involved in direct cytotoxicity, but are highly specialized to present tumor antigens to host or co-transfused lymphoid immune cells [19]. Due to this mostly indirect effect, they are sometimes subsumed under the broader field of cancer vaccines. CAR-DC have been demonstrated effective against acute myeloid leukemia in preclinical studies [19,20] and are being studied in human against solid epithelial malignancies (NCT05631899 & NCT05631886).

The macrophage / monocyte family presents an intermediate between neutrophils and dendritic cells, both involved in direct cytotoxicity and phagocytosis, as well as antigen presentation. Expert cytokine producers, macrophages are probably the most apt at modifying the local tumor immune microenvironment and have thus been extensively engineered with cytokine / interferon constructs inside and outside of CAR-design [6-8]. Considering this data, macrophages may lend themselves especially to fourth- generation CAR, combining direct tumor cell killing with a rebalancing of the immune microenvironment. Macrophages are also so far the only myeloid cell type that has been demonstrated to induce lasting cancer regression in a subset of model animals [5].

Cell Source

Monocytes can be derived autologously and can be differentiated into dendritic cells or macrophages ex vivo before re-transfusion. While an autologous approach circumnavigates most concerns about graft-vs-host disease (or an immune-related short therapy persistence vice versa), it also carries tremendous costs, due to the intrinsic incompatibility with standardized mass-production. In addition, monocyte and macrophage lentiviral transduction is at best in experimental stages [21]; thus relying on adenovirus or mRNA-based overexpression, which may further limit their effective duration in vivo. However, other than most cell therapies, myeloid cells are capable of auto- tolerance induction and may hence not require (exact) HLA- matching [3,22,23]. Due to all these reasons, myeloid cells lend themselves especially well to large-scale production from either primary (e.g., cord-blood derived) CD34+ cells or an unlimited supply of pluripotent stem cells. The latter, while accruing steep initial costs to establish a cGMP-grade line [24], come at the additional benefit of long-term stable gene-editing and could be banked from a relatively small number of haplo-matched donors [25], if necessary for cross-tolerance.

Many publications have demonstrated the efficacy of CAR myeloid cells in preclinical models, with a few even reporting permanent tumor control in animal models. However, considering this technology has now entered clinical phases, many details of this exciting new therapy have yet to be sufficiently clarified. We raise the following points that

1. Which chimeric signaling domain stimulates which myeloid cell function, and how does that affect tumor cell killing and anti-tumor immunity?
2. Are anti-tumor matrix CD147-domains best used in addition to stimulatory domains, or alone?
3. Does the addition of cytokine genes robustly enhance priming of host immunity? Which cytokines are the most advantageous? How is the risk of an overshooting systemic immune response addressed?
4. Which myeloid cell, or immune cell combination, is best used for which tumor type to optimize direct and indirect anti-tumor effects?
5. Is it appropriate to use the same CAR-design in different immune cells, e.g., myeloid and T-cells, simplifying bulk and in vivo reprogramming?

As CD3ζ-based designs have been proven effective in many preclinical studies, they should be considered the benchmark for novel CAR designs. New designs should thus not only be compared to truncated CAR negative controls, but also CD3ζ- positive controls in key metrics, like animal survival and tumor size.

To collect preclinical publications, we first performed a non-systematic search of Pubmed and Google.com for an initial collection. In a second step, we expanded this list using ResearchRabbit.ai and ConnectedPapers.com. Journal publications and conference abstracts written in English were eligible for inclusion if enough information about cell types, effect, and CAR design was provided.

To collect clinical studies, we systematically searched clinicaltrials.gov for studies on myeloid CAR interventions using the search terms “Myeloid AND CAR” (91 results), “Macrophage AND CAR” (6), “Monocyte AND CAR” (4), “Neutrophil AND CAR” (1), “Granulocyte AND CAR” (6), “Dendritic AND CAR” (8), “PBMC AND CAR” (76), and “CAR NOT T cell” (414). The last search was performed on Apr 19, 2024. All results were screened for relevance to this study. NCT05007379 had initially been included in the screening but was excluded in the full-text screen for not involving an intervention (observational study). If sufficient details about the therapy product could not be attained from the study description or from linked publications [26], we performed a secondary non-systematic search via Pubmed & Google.com, where we found the cell types and CAR designs used in NCT06254807 & NCT04660929 in a published presentation of the producing company [27].

Tables

Examples of CD3ζ CAR designs that demonstrated effectiveness in myeloid cells in preclinical studies. AThe interferon γ gene was co-transfected as part of the CAR construct to M1-prime macrophages. BThe antigen-binding domain contains the scorpion-venom chlorotoxin, which avidly binds to chloride channels found at high density in glioma and glioblastoma. M, Macrophage/Monocyte. N, Neutrophil. DC, Dendritic cell.

Examples of CAR specifically designed for myeloid cells that demonstrated therapy effectiveness in preclinical studies. We standardized the results as following: + superior effect of myeloid-specific design over CD3-based design in key measure; (+) superior effect demonstrated outside of key measures;- myeloid design inferior or non-superior to CD3ζ in most measures. n.s., not studied, the novel receptor design was not compared to CD3 CAR designs. AThis design uses CD3ζ as signaling domain but added CD147 to enhance production of matrix metalloproteinases by myeloid cells. BEffect not compared to CD3ζ alone, but worse, than the paired design without 4-1BB. CThe available data is incompletely labeled but suggestive of no significant difference between TIR and CD3ζ CAR design. M, Macrophage/Monocyte. N, Neutrophil. TLR, Toll-like receptor. TIR, Toll-Interleukin Receptor domain.

Clinical trials registered on clinicaltrials.gov using CAR in myeloid cell types on Apr 19, 2024. Also see Methods section. CAR designs are denoted as “–(Hinge)-(Transmembrane)- (Intracellular)” domains. n/a, not available.

Figures

Overview of proposed and studied T-cell [40,41] and myeloid [14,36] CAR designs with examples of common stimulatory, co- stimulatory, and added signaling domains.

This work was supported by grants from the Werner Jackstädt Stiftung (WB), NIH/NEI (R01EY032113; ETZ), The Maryland Stem Cell Research Fund (2023-MSCRFV-5995; 2023-MSCRFV-6248; ETZ), and The Lisa Dean Moseley Foundation (ETZ). Figure 1 was created with licensed Biorender software.

1. Styczy?ski J. A brief history of CAR-T cells: from laboratory to the bedside. Acta Haematol Polon. 2020; 51: 2-5.
2. Sterner RC, Sterner RM. CAR-T cell therapy: current limitations and potential strategies. Blood Cancer J. 2021; 11: 69.
3. Buys W, Zambidis ET. Harnessing bioengineered myeloid progenitors for precision immunotherapies. NPJ Regen Med. 2023; 8: 66.
4. Chang Y, Cai X, Syahirah R, Yao Y, Xu Y, Jin G, et al. CAR-neutrophil mediated delivery of tumor-microenvironment responsive nanodrugs for glioblastoma chemo-immunotherapy. Nat Commun. 2023; 14: 2266.
5. Klichinsky M, Ruella M, Shestova O, Lu XM, Best A, Zeeman M, et al. Human chimeric antigen receptor macrophages for cancer immunotherapy. Nat Biotechnol. 2020; 38: 947-53.
6. Kaczanowska S, Beury DW, Gopalan V, Tycko AK, Qin H, Clements ME, et al. Genetically engineered myeloid cells rebalance the core immune suppression program in metastasis. Cell. 2021; 184: 2033-52.e21.
7. Wu M, Hussain S, He Y-H, Pasula R, Smith PA, Martin WJ. Genetically engineered macrophages expressing IFN- gamma restore alveolar immune function in scid mice. Proc Natl Acad Sci U S A. 2001; 98: 14589-94.
8. Kang M, Lee SH, Kwon M, Byun J, Kim D, Kim C, et al. Nanocomplex- Mediated In Vivo Programming to Chimeric Antigen Receptor-M1 Macrophages for Cancer Therapy. Adv Mater. 2021; 33: e2103258.
9. Hirobe S, Imaeda K, Tachibana M, Okada N. The Effects of Chimeric Antigen Receptor (CAR) Hinge Domain Post-Translational Modifications on CAR-T Cell Activity. Int J Mol Sci. 2022; 23: 4056.
10. Kunkiel J, Gödecke N, Ackermann M, Hoffmann D, Schambach A, Lachmann N, et al. The CpG-sites of the CBX3 ubiquitous chromatin opening element are critical structural determinants for the anti- silencing function. Sci Rep. 2017; 7: 7919.
11. Abdin SM, Paasch D, Kloos A, Oliveira MC, Jang MS, Ackermann M, et al. Scalable generation of functional human iPSC-derived CAR- macrophages that efficiently eradicate CD19-positive leukemia. J Immunother Cancer. 2023; 11: e007705.
12. Niu Z, Chen G, Chang W, Sun P, Luo Z, Zhang H, et al. Chimeric antigen receptor-modified macrophages trigger systemic anti-tumour immunity. J Pathol. 2021; 253: 247-57.
13. Kawai T, Akira S. The role of pattern-recognition receptors in innate immunity: update on Toll-like receptors. Nat Immunol. 2010; 11: 373-84.
14. Zhang J, Lei A, Tian L, Zhang L, Lu S, Lu H, et al. The Second Generation of Human iPSC-Derived CAR-Macrophages for Immune Cell Therapies in Liquid and Solid Tumors. Blood. 2022; 140: 9238-9239.
15. Administration UFaD. FDA Investigating Serious Risk of T-cell Malignancy Following BCMA-Directed or CD19-Directed Autologous Chimeric Antigen Receptor (CAR) T cell Immunotherapies. fda. gov2023.
16. Vinay DS, Kwon BS. 4-1BB signaling beyond T cells. Cell Mol Immunol. 2011; 8: 281-284.
17. Yang B, Wang X, Wei X, Ma J. Development of a novel HER2-CAR monocyte cell therapy with controllable proliferation and enhanced anti-tumor efficacy. Chin Med J (Engl). 2024.
18. Coffelt SB, Kersten K, Doornebal CW, Weiden J, Vrijland K, Hau C-S, et al. IL-17-producing γδ T cells and neutrophils conspire to promote breast cancer metastasis. Nature. 2015; 522: 345-8.
19. Suh HC, Pohl K, Javier APL, Slamon DJ, Chute JP. Effect of dendritic cells (DC) transduced with chimeric antigen receptor (CAR) on CAR T-cell cytotoxicity. J Clin Oncol. 2017; 35: 144.
20. Suh HC, Pohl KA, Termini C, Kan J, Timmerman JM, Slamon DJ, Chute JP. Bioengineered Autologous Dendritic Cells Enhance CAR T Cell Cytotoxicity By Providing Cytokine Stimulation and Intratumoral Dendritic Cells. Blood. 2018; 132: 3693.
21. Bobadilla S, Sunseri N, Landau NR. Efficient transduction of myeloid cells by an HIV-1-derived lentiviral vector that packages the Vpx accessory protein. Gene Ther. 2013; 20: 514-20.
22. Price TH, McCullough J, Strauss RG, Ness PM, Hamza TH, Harrison RW, Assmann SF. WBC alloimmunization: effects on the laboratory and clinical endpoints of therapeutic granulocyte transfusions. Transfusion. 2018; 58: 1280-1288.
23. Cai S, Choi JY, Borges TJ, Zhang H, Miao J, Ichimura T, et al. Donor myeloid derived suppressor cells (MDSCs) prolong allogeneic cardiac graft survival through programming of recipient myeloid cells in vivo. Sci Rep. 2020; 10: 14249.
24. Bravery C. Do Human Leukocyte Antigen-Typed Cellular Therapeutics Based on Induced Pluripotent Stem Cells Make Commercial Sense? Stem Cells Dev. 2015; 24: 1-10.
25. Taylor CJ, Bolton EM, Pocock S, Sharples LD, Pedersen RA, Bradley JA. Banking on human embryonic stem cells: estimating the number of donor cell lines needed for HLA matching. Lancet. 2005; 366: 2019- 25.
26. Zhang W, Liu L, Su H, Liu Q, Shen J, Dai H, et al. Chimeric antigen receptor macrophage therapy for breast tumours mediated by targeting the tumour extracellular matrix. Br J Cancer. 2019; 121: 837-845.
27. HARNESSING THE POWER OF MACROPHAGES [press release]. 2024.
28. Zhang J, Webster S, Duffin B, Bernstein MN, Steill J, Swanson S, et al. Generation of anti-GD2 CAR macrophages from human pluripotent stem cells for cancer immunotherapies. Stem Cell Reports. 2023; 18: 585-596.
29. Chen Y, Zhu X, Liu H, Wang C, Chen Y, Wang H, et al. The application of HER2 and CD47 CAR-macrophage in ovarian cancer. J Transl Med. 2023; 21: 654.
30. Harris JD, Chang Y, Syahirah R, Lian XL, Deng Q, Bao X. Engineered anti-prostate cancer CAR-neutrophils from human pluripotent stem cells. J Immunol Regen Med. 2023; 20: 100074.
31. Majumder A, Jung HS, Zhang J, Suknuntha K, Thomson J, Slukvin I. 356 Generation of GD2-CAR neutrophils from hPSCs for targeted cancer immunotherapy of solid tumors. J ImTherap Cancer. 2022; 10: A375.
32. Chang Y, Syahirah R, Wang X, Jin G, Torregrosa-Allen S, Elzey BD, et al. Engineering chimeric antigen receptor neutrophils from human pluripotent stem cells for targeted cancer immunotherapy. Cell Rep. 2022; 40: 111128.
33. Huo Y, Zhang H, Sa L, Zheng W, He Y, Lyu H, et al. M1 polarization enhances the antitumor activity of chimeric antigen receptor macrophages in solid tumors. J Transl Med. 2023; 21: 225.
34. Morrissey MA, Williamson AP, Steinbach AM, Roberts EW, Kern N, Headley MB, et al. Chimeric antigen receptors that trigger phagocytosis. Elife. 2018; 7: e36688.
35. Zhang L, Tian L, Dai X, Yu H, Wang J, Lei A, et al. Pluripotent stem cell- derived CAR-macrophage cells with antigen-dependent anti-cancer cell functions. J Hematol Oncol. 2020; 13: 153.
36. Lei A, Yu H, Lu S, Lu H, Ding X, Tan T, et al. A second-generation M1- polarized CAR macrophage with antitumor efficacy. Nat Immunol. 2024; 25: 102-116.
37. Wu S-Y, Wu K, Tyagi A, Xing F, Zhao D, Deshpande RP, et al. Abstract 6153: MyD88-mediated chimeric antigen receptor macrophage suppresses brain metastasis by target-specific phagocytosis and bystander effect through TNF-α. Cancer Res. 2022; 82: 6153.
38. Dong X, Fan J, Xie W, Wu X, Wei J, He Z, et al. Efficacy evaluation of chimeric antigen receptor-modified human peritoneal macrophages in the treatment of gastric cancer. Br J Cancer. 2023; 129: 551-562.
39. Duan Z, Li Z, Wang Z, Chen C, Luo Y. Chimeric antigen receptor macrophages activated through TLR4 or IFN-γ receptors suppress breast cancer growth by targeting VEGFR2. Cancer Immunol Immunother. 2023; 72: 3243-3257.
40. Reis A. ProteoBlog: ProteoGenix. AUGUST 3 2021.
41. Asmamaw Dejenie T, Tiruneh G/Medhin M, Dessie Terefe G, Tadele Admasu F, Wale Tesega W, Chekol Abebe E. Current updates on generations, approvals, and clinical trials of CAR T-cell therapy. Hum Vaccin Immunother. 2022; 18: 2114254.