{
  "abstract": "Background Cancer immunotherapy harnesses the immune system to recognise and eliminate cancer cells, with tumour-infiltrating lymphocytes (TILs) playing a pivotal role in anti-tumour responses. However, the dynamic behaviour of TILs within the tumour microenvironment (TME) remains not yet fully understood. This study aimed to investigate and visualise the spatiotemporal dynamics of TILs in vivo using a breast cancer model.Methods Three breast cancer cell lines (4T1: mouse breast cancer, MDA-MB-231, and MCF-7: human breast cancer) were orthotopically implanted into mice to establish distinct breast cancer models. To visualise TIL dynamics in vivo, T cells endogenously expressing fluorescent protein were used. Intravital microscopy (IVM) was employed to monitor TIL behaviour and motility within the TME in real time.Results As a result, we observed increased TIL motility within tumours compared to peritumoural regions in the 4T1 model. Comparatively, TIL dynamics varied significantly across models: in MCF-7 tumours, TILs displayed more active and rapid migration, while in MDA-MB-231 tumours, TIL motility was significantly more constrained.Conclusions Our study demonstrates the utility of intravital microscopy in capturing the real-time dynamics of TILs within the TME. The observed inter-model differences in TIL motility underscore the influence of tumour-specific factors on immune cell behaviour. These findings support the value of IVM in preclinical immunotherapy research and enhance our understanding of immune-tumour interactions, potentially informing strategies for more effective immunotherapies.Ethics Approval The experiments with human cancer cell lines were approved by the Institutional Review Board of Seoul National University Bundang Hospital (SNUBH) (protocol No. X-2012/655-902). All animal experiments were conducted following the standard guidelines for the care and use of laboratory animals and were approved by the Institutional Animal Care and Use Committee of Korea Advanced Institute of Science and Technology (protocol No. 2013–30) and SNUBH (protocol No. BA-2012-309-107-01).",
  "authors": [
    {
      "affiliations": [
        "IVIM Technology, Seoul, Republic of Korea"
      ],
      "name": "Jenny Junghyon Ohm"
    },
    {
      "affiliations": [
        "IVIM Technology, Seoul, Republic of Korea"
      ],
      "name": "Hyunseok Kim"
    },
    {
      "affiliations": [
        "IVIM Technology, Seoul, Republic of Korea"
      ],
      "name": "Hyungjin Kwon"
    },
    {
      "affiliations": [
        "IVIM Technology, Seoul, Republic of Korea"
      ],
      "name": "Sungwoon Yoon"
    },
    {
      "affiliations": [
        "IVIM Technology, Seoul, Republic of Korea"
      ],
      "name": "Sowon Lee"
    },
    {
      "affiliations": [
        "IVIM Technology, Seoul, Republic of Korea"
      ],
      "name": "Hsuan-Ju Chen"
    },
    {
      "affiliations": [
        "IVIM Technology, Seoul, Republic of Korea"
      ],
      "name": "Junyoung Park"
    },
    {
      "affiliations": [
        "IVIM Technology, Seoul, Republic of Korea"
      ],
      "name": "Kubra Akyildiz"
    }
  ],
  "title": "840 In vivo imaging of tumor infiltrating lymphocyte dynamics and distribution in a breast cancer model",
  "uid": "c5542312-dff6-5917-bda2-707518006ec4"
}