Antitumor Activity Of Tumor-infiltrating Lymphocytes Research Articles

3D tumor spheroids promote activation, expansion, and anti-tumor effects of tumor-infiltrating lymphocytes in vitro

The adoptive immunotherapy mediated by tumor-infiltrating lymphocytes (TILs) has shown definite efficacy against various solid tumors. However, the inefficiency of the conventional method based on in vitro expansion of TILs fails to achieve the cell count and high tumor-killing activity required for therapeutic purposes. This study investigated the effect of 3D tumor spheroids on the activation and expansion of TILs in vitro, aiming to provide a novel approach for the expansion of TILs. We procured TILs and primary tumor cells from surgical samples of lung cancer patients and then compared the impacts of lung cancer cell line NCI-H1975 and primary lung cancer cells cultured under 2D and 3D conditions on the activation, expansion, and anti-tumor activity of TILs. Furthermore, we added the programmed cell death protein 1 (PD-1) antibody into the co-culture of primary tumor cells and TILs within a 3D environment to assess the effects of the antibody on TILs. The results showed that compared with 2D cultured tumor cells, the 3D cultured H1975 cells significantly enhanced the expansion of TILs, increasing the proportion of CD3+/CD8+ cells in TILs to 61.6%. The 3D primary tumor model also enhanced the proportion of CD3+/CD8+ cells in TILs (45.5%, 54.4%), induced apoptosis of tumor epithelial cells and decreased the overall tumor cells survival rate (16.7%) after co-culture. PD-1 antibodies further improved the in vitro expansion capacity of TILs mediated by 3D tumor spheroids, resulting in the proportions of 50.9% and 57.0% for CD3+/CD8+ cells and enhancing the antitumor activity significantly (reducing the overall tumor survival rate to 9.36%). In summary, the use of 3D tumor spheroids significantly promoted the expansion and improved the anti-tumor effect of TILs, and the use of the PD-1 antibody further promoted the expansion and tumor-killing effect of TILs.

Tumor-infiltrating lymphocytes: opportunities to use their potential in clinical practice in breast cancer

Introduction. Tumor-infiltrating lymphocytes are currently considered as a prognostic biomarker of cancer patient survival and response to therapy, as well as a target for immunotherapy. However, tumor-infiltrating lymphocytes are only part of the tumor microenvironment, which consists of cellular and cytokine components. The cellular component also includes tumor-associated macrophages, neutrophils, fibroblasts and other cells. The cytokine component is represented by the products of the activity of all cells of the microenvironment, as well as tumor cells. The purpose of this review is to consider various subpopulations of tumor-infiltrating lymphocytes, show their interaction with tumor cells and other cell populations of the tumor microenvironment, and also evaluate the possibilities of clinical use of this cell population as a biomarker using the example of breast cancer. Material and research methods. Materials for evaluating the importance of tumor-infiltrating lymphocytes as one of the components of the tumor microenvironment for clinical practice were publications in domestic and foreign journals over the past 5-7 years. Results. This review examines various subpopulations of tumor-infiltrating lymphocytes, shows their interaction with tumor cells and other cell populations of the tumor microenvironment, and also describes the potential for clinical use of this cell population as a biomarker for predicting clinical outcomes and the possibility of their use to determine the most effective treatment for cbreast cancer. Conclusion. Obtaining new data on the previously poorly studied components of the tumor microenvironment and tumor-infiltrating lymphocytes, as well as the formation of ideas about the mutual influence of tumor microenvironment cells and tumor cells open up the prospect of developing innovative models of therapy. One of the modern directions is the search for molecular mechanisms of maintaining the antitumor activity of tumor-infiltrating lymphocytes, as well as the polarization of cells in the tumor microenvironment. Advances in the field of molecular oncology will make it possible to reduce the mortality rate of cancer patients to minimal levels while maintaining or even improving their standard of living.

Tumor-infiltrating lymphocyte: features and prognosis of lymphocytes infiltration on colorectal cancer

ABSTRACT Tumor-infiltrating lymphocytes (TILs) are vital elements of the tumor microenvironment (TME), and the anti-tumor activity of TILs on colorectal cancer (CRC) has been a topic of concern. However, the characteristics and prognosis of the various types of lymphocyte infiltration in CRC have not been fully explained. Our study aimed to identify distinct features and prognosis of TILs. We integrated multiple-cohort databases to illustrate the features, proportions, and prognosis of TILs on CRC. We found that macrophages were significantly enriched in CRC. When we used the scRNA-seq database to further evaluate the proportion of TILs, we noticed markedly higher numbers of CD4 + T cell, B cell, and CD8 + T cell in four Gene Expression Omnibus Series (GSE) CRC cohorts. Interestingly, we found that the infiltrating level of TIL subgroups from highest to lowest is always dendritic cells, CD8 + T cells, CD4 + T cells, neutrophils, B cells, and macrophages; the proportion of infiltration is largely constant regardless of mutations in specific genes or somatic copy number variation (sCNV). In addition, the data corroborated that CD4+ TILs and CD8+ TILs have certain application values in the prognosis of CRCs, and age negatively related to CD8+ TILs and B plasma infiltration. Finally, patients with CRC who are older than 70 years have a better response to immune-checkpoint blockade.

Tet2 Inactivation Enhances the Antitumor Activity of Tumor-Infiltrating Lymphocytes.

Inactivation of tumor-infiltrating lymphocytes (TIL) is one of the mechanisms mitigating antitumor immunity during tumor onset and progression. Epigenetic abnormalities are regarded as a major culprit contributing to the dysfunction of TILs within tumor microenvironments. In this study, we used a murine model of melanoma to discover that Tet2 inactivation significantly enhances the antitumor activity of TILs with an efficacy comparable to immune checkpoint inhibition imposed by anti-PD-L1 treatment. Single-cell RNA-sequencing analysis suggested that Tet2-deficient TILs exhibit effector-like features. Transcriptomic and ATAC-sequencing analysis showed that Tet2 ablation reshapes chromatin accessibility and favors binding of transcription factors geared toward CD8+ T-cell activation. Furthermore, the ETS family of transcription factors contributed to augmented CD8+ T-cell function following Tet2 depletion. Overall, our study establishes that Tet2 constitutes one of the epigenetic barriers that account for dysfunction of TILs and that Tet2 inactivation could promote antitumor immunity to suppress tumor growth. SIGNIFICANCE: This study suggests that ablation of TET2+ from TILs could promote their antitumor function by reshaping chromatin accessibility for key transcription factors and enhancing the transcription of genes essential for antitumor activity.

Abstract PO-005: Tet2 inactivation enhances the anti-tumor efficiency of tumor-infiltrating lymphocytes (TILs)

Abstract Inactivation of tumor infiltrating lymphocytes (TILs) is one of the mechanisms mitigating anti-tumor immunity during tumor onset and progression. Epigenetic abnormalities are regarded as a major culprit contributing to the dysfunction of TILs within tumor microenvironments. In this study, we used a murine model of melanoma to discover that Tet2 inactivation significantly enhances the anti-tumor activity of TILs, with the efficacy comparable to immune checkpoint inhibition imposed by anti-PD-L1 treatment. Single-cell RNA-seq analysis further revealed that Tet2-deficient TILs exhibit effector-like features. Transcriptomic and ATAC-seq analysis further demonstrated that Tet2 deletion reshapes the chromatin accessibility and favors the binding of transcription factors geared toward CD8+ T cell activation. In summary, our study establishes that Tet2 constitutes one of the epigenetic barriers contributing to dysfunction of TILs, and that Tet2 inactivation could benefit anti-tumor immunity to boost tumor suppression. Citation Format: Minjung Lee, Jiangfang Li, Shaohai Fang, Wei Han, Margarita Moczygemba, Yubin Zhou, Jia Li, Deqiang Sun, Yun Huang. Tet2 inactivation enhances the anti-tumor efficiency of tumor-infiltrating lymphocytes (TILs) [abstract]. In: Abstracts: AACR Special Virtual Conference on Epigenetics and Metabolism; October 15-16, 2020; 2020 Oct 15-16. Philadelphia (PA): AACR; Cancer Res 2020;80(23 Suppl):Abstract nr PO-005.

The effects of targeted immune-regulatory strategies on tumor-specific T-cell responses in vitro.

Immune-related adverse events (IrAEs) are auto-immune reactions associated with immune checkpoint inhibitor-based therapy (ICI). Steroids are currently the first-line option for irAE management; however, recent studies have raised concerns regarding their potential impairment of tumor-specific immune responses. In this study, we investigated the in vitro effects of commonly used irAE treatment drugs on the anti-tumor activity of tumor-infiltrating lymphocytes (TILs). Impairment of anti-tumor immune responses by four drugs (antibodies: vedolizumab and tocilizumab; small molecules: mycophenolate mofetil and tacrolimus) reported to be effective in treating irAEs was tested at clinically relevant doses in vitro and compared to a standard moderate dose of corticosteroids (small molecules) or infliximab (antibodies). TIL responses against autologous tumor cell lines, in the presence or absence of irAE drugs, were determined by flow cytometry (short-term tumor-specific T-cell activation) or xCELLigence (T-cell-mediated tumor killing). None of the tested antibodies influenced T-cell activation or T-cell-mediated tumor killing. Low-dose mycophenolate and tacrolimus did not influence T-cell activation, whereas higher doses of tacrolimus (> 1ng/ml) impaired T-cell activation comparably to dexamethasone. All tested small molecules impaired T-cell-mediated tumor killing, with high-dose tacrolimus reducing killing at levels comparable to dexamethasone-mediated inhibition. In addition, mycophenolate and tacrolimus alone also demonstrated anti-proliferative effects on tumor cells. These data support clinical testing of targeted immune-regulatory strategies in the initial phase of irAE management, as a potential replacement for corticosteroids.

Tet2 Inactivation Enhances the Anti-Tumor Activity of Tumor-Infiltrating Lymphocytes (TILs) to Curtail Melanoma Growth

Inactivation of tumor infiltrating lymphocytes (TILs) is one of the mechanisms mitigating anti-tumor immunity during tumor onset and progression. Epigenetic abnormalities are regarded as a major culprit contributing to the dysfunction of TILs within tumor microenvironments. In this study, we used a murine model of melanoma to discover that Tet2 inactivation significantly enhances the anti-tumor activity of TILs, with the efficacy comparable to immune checkpoint inhibition imposed by anti-PD-L1 treatment. Single-cell RNA-seq analysis further revealed that Tet2-deficient TILs exhibit effector-like features. Transcriptomic and ATAC-seq analysis further demonstrated that Tet2 deletion reshapes the chromatin accessibility and favors the binding of transcription factors geared toward CD8+ T cell activation. In summary, our study establishes that Tet2 constitutes one of the epigenetic barriers contributing to dysfunction of TILs, and that Tet2 inactivation could benefit anti-tumor immunity to boost tumor suppression. Disclosures No relevant conflicts of interest to declare.

FAM83H overexpression predicts worse prognosis and correlates with less CD8+ T cells infiltration and Ras-PI3K-Akt-mTOR signaling pathway in pancreatic cancer.

Family with sequence similarity 83 members H (FAM83H) is one member of Family with sequence similarity 83 (FAM83) family, which possess oncogenic properties in several types of cancer. However, the potential function of FAM83H in pancreatic cancer (PC) still remain unknown. This study aims to explore the role of FAM83H during pancreatic carcinogenesis and the regulation of immune infiltration in PC. In the current study, the clinical significance and potential biological of FAM83H were evaluated by bioinformatics analysis. Possible associations between FAM83H expression and tumor immunity were analyzed using ESTIMATE algorithm and single-sample gene set enrichment analysis (ssGSEA). FAM83H expression was significantly upregulated in tumor tissues, and positively associated with higher histologic grade, tumor recurrence, and worse prognosis. FAM83H overexpression is notably associated with KRAS activation. And functional enrichment analysis demonstrated that FAM83H may be involved in positive regulation of cell proliferation and migration, Ras protein signal transduction, regulation of cell-matrix adhesion, epithelial to mesenchymal transition (EMT), TGF-β receptor signaling in EMT, and activated NOTCH transmits signal to the nucleus. ESTIMATE algorithm and ssGSEA demonstrated that FAM83H overexpression suppressed the infiltration and antitumor activity of tumor-infiltrating lymphocytes (TILs), especially for CD8+ T cells. Besides, FAM83H overexpression significantly correlated with low expression of TIL-related gene markers (e.g. CD8A, CD8B, CD2, CD3D, and CD3E). The study suggests that FAM83H overexpression predicts poor prognosis and correlates with less CD8+ T cells infiltration and Ras-PI3K-Akt-mTOR signaling pathway in PC.

Role of the Neutrophil in the Pathogenesis of Advanced Cancer and Impaired Responsiveness to Therapy.

Notwithstanding the well-recognized involvement of chronic neutrophilic inflammation in the initiation phase of many types of epithelial cancers, a growing body of evidence has also implicated these cells in the pathogenesis of the later phases of cancer development, specifically progression and spread. In this setting, established tumors have a propensity to induce myelopoiesis and to recruit neutrophils to the tumor microenvironment (TME), where these cells undergo reprogramming and transitioning to myeloid-derived suppressor cells (MDSCs) with a pro-tumorigenic phenotype. In the TME, these MDSCs, via the production of a broad range of mediators, not only attenuate the anti-tumor activity of tumor-infiltrating lymphocytes, but also exclude these cells from the TME. Realization of the pro-tumorigenic activities of MDSCs of neutrophilic origin has resulted in the development of a range of adjunctive strategies targeting the recruitment of these cells and/or the harmful activities of their mediators of immunosuppression. Most of these are in the pre-clinical or very early clinical stages of evaluation. Notable exceptions, however, are several pharmacologic, allosteric inhibitors of neutrophil/MDSC CXCR1/2 receptors. These agents have entered late-stage clinical assessment as adjuncts to either chemotherapy or inhibitory immune checkpoint-targeted therapy in patients with various types of advanced malignancy. The current review updates the origins and identities of MDSCs of neutrophilic origin and their spectrum of immunosuppressive mediators, as well as current and pipeline MDSC-targeted strategies as potential adjuncts to cancer therapies. These sections are preceded by a consideration of the carcinogenic potential of neutrophils.

Abstract B154: Differential effects of corticosteroids and anti-TNF on tumor-specific immune responses— Implications for the management of irAEs

Abstract Background: Up to 60% of patients treated with cancer immunotherapy develop severe or life threatening immune-related adverse events (irAEs). Immunosuppression with high doses of corticosteroids or, in refractory cases, with tumor necrosis factor (TNF) antagonists, are the mainstay of treatment for irAEs. It is currently unknown what is the impact of corticosteroids and anti-TNF on the activity of antitumor T-cells. Methods: The influence of clinically relevant doses of dexamethasone (corresponding to an oral dose of 10 to 125 mg prednisolone) and infliximab (anti-TNF) on the activation and killing capacity of tumor-infiltrating lymphocytes (TILs) was tested in vitro. Results: Overall, dexamethasone at low or intermediate/high dose impaired the activation (respectively -46% and -62% in n=8) and tumor-killing ability (respectively -48% and -53% in n=6) of tumor-specific TILs. In contrast, a standard clinical dose of infliximab only had a minor effect on T-cell activation and tumor killing (respectively -20% in n=8 and -10% in n=6). A brief resting following exposure to dexamethasone was sufficient to rescue the in vitro activity of TILs. Conclusions: Clinically relevant doses of infliximab only influenced to a lesser extent the activity of tumor-specific TILs in vitro, whereas even low doses of corticosteroids markedly impaired the antitumor activity of TILs. These data support steroid-sparing strategies and early initiation of anti-TNF for the treatment of irAEs in immuno-oncology. Citation Format: Marco Donia, Troels H. Borch, Haja D. Radic, Christopher Chamberlain, Aishwarya Gokuldass, Inge Marie Stentoft Svane, Arianna Draghi. Differential effects of corticosteroids and anti-TNF on tumor-specific immune responses— Implications for the management of irAEs [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B154.

Induction of Tertiary Lymphoid Structures With Antitumor Function by a Lymph Node-Derived Stromal Cell Line

Tertiary lymphoid structures (TLSs) associate with better prognosis in certain cancer types, but their underlying formation and immunological benefit remain to be determined. We established a mouse model of TLSs to study their contribution to antitumor immunity. Because the stroma in lymph nodes (sLN) participates in architectural support, lymphogenesis, and lymphocyte recruitment, we hypothesized that TLSs can be created by sLN. We selected a sLN line with fibroblast morphology that expressed sLN surface markers and lymphoid chemokines. The subcutaneous injection of the sLN line successfully induced TLSs that attracted infiltration of host immune cell subsets. Injection of MC38 tumor lysate-pulsed dendritic cells activated TLS-residing lymphocytes to demonstrate specific cytotoxicity. The presence of TLSs suppressed MC38 tumor growth in vivo by improving antitumor activity of tumor-infiltrating lymphocytes with downregulated immune checkpoint proteins (PD-1 and Tim-3). Future engineering of sLN lines may allow for further enhancements of TLS functions and immune cell compositions.

Abstract P1-09-10: ICOSL anti-HER2 V-mAbs: Localizing engineered ICOSL costimulatory agonists to HER2+ tumors through trastuzumab

Abstract Background: The presence of tumor infiltrating lymphocytes (TILs) has been associated with improved prognosis in HER2+ breast cancer patients. Antigen specific TCR and costimulatory receptor signaling drive increases in TIL number, effector function, and tumor cytotoxicity. Improving the number and effector phenotype of tumor localized TILs has curative potential by enhancing the adaptive and memory immune response. Targeting HER2 with the monoclonal anti-HER2 antibody trastuzumabhas improved survival in HER2+ breast cancer patients and is known to increase peripheral type I immunity, which may be reflected by increased TILs. The Immunoglobulin Superfamily (IgSF) includes a large, diverse family of immunotherapy targets expressed on immune cells and tumors. Transmembrane IgSF receptors,CD28 and inducible T cell co-stimulator (ICOS), related costimulatory molecules expressed on T cells, interact with CD80/CD86 and ICOS ligand (ICOSL), respectively, and play critical roles in T cell activation and adaptive immunity.The Alpine Immune Science's VIgDTM platform uses directed evolution to derive novel, therapeutically-applicable IgSF extracellular domains with tailored specificity and affinity. The vIgD platform has generated human ICOSL vIgDs capable of binding both ICOS and CD28, activating both pathways. To promote anti-tumor activity of TILs in HER2+ tumors, we developed trastuzumab-ICOSL “V-mAbs” consisting of trastuzumab fused to activating ICOSL vIgDs. These V-mAbs are designed to localize to HER2+ tumors and activate antigen-specific, resident T-cells through costimulatory receptor agonism. Methods: V-mAbs were generated by fusing ICOSL vIgDs to either the N- or C- termini of the heavy and/or light chains of trastuzumab. V-mAb binding to CD28, ICOS or HER2 was measured by flow cytometric analysis of transfected cells or ForteBio analysis. V-mAb costimulatory activity was confirmed by immobilization in the presence of anti-CD3 in a primary human T cell assay. Finally, V-mAbs were co-cultured with HER2+ target cells and human T cells; T-cell activity was measured by proliferation, cytokine production, and target lysis. Results: V-mAbs were successfully produced and bound to CD28, ICOS and HER2. In a plate bound costimulation assay, the V-mAbs increased the amount of IFN-gamma produced by T-cells stimulated with anti-CD3. When incubated with HER2+ target cells, V-mAbs promoted T-cell proliferation, cytokine secretion, and target cell lysis. Data from in vivo studies, to determine the impact of trastuzumab V-mAbs on HER2+ cancers, will be presented when available. Conclusions: Trastuzumab-ICOSL V-mAbs are novel ICOS- and CD28-activating immunotherapies for HER2-positive tumors, promoting T-cell proliferation, cytokine secretion, and target cell lysis in a HER2 dependent fashion. The V-mAb platform has broad potential to enable tumor-localized immune modulation via the diverse array of IgSF members. Preclinical development of trastuzumab-ICOSL clinical therapeutics is in progress. Citation Format: Rickel E, Evans L, Swanson R, Levin SS, Rixon M, Wolfson M, Bhandari J, MacNeil S, Hoover J, Kornacker M, Capuano I, Peng SL. ICOSL anti-HER2 V-mAbs: Localizing engineered ICOSL costimulatory agonists to HER2+ tumors through trastuzumab [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-09-10.

Specific antitumor activity of tumor-infiltrating lymphocytes expanded first in a culture with both anti-CD3 monoclonal antibody and activated B cells and then in a culture with interleukin-2

Specific antitumor activity of tumor-infiltrating lymphocytes expanded first in a culture with both anti-CD3 monoclonal antibody and activated B cells and then in a culture with interleukin-2

Specific antitumor activity of tumor-infiltrating lymphocytes expanded first in a culture with both anti-CD3 monoclonal antibody and activated B cells and then in a culture with interleukin-2.

In order to expand tumor-infiltrating lymphocytes (TIL) efficiently and in order to use them for immunotherapy, we utilized lipopolysaccharide-activated B cells (LPS blasts) as costimulatory-signal-providing cells in an in vitro culture system. TIL, prepared from subcutaneously inoculated B16 melanoma, failed to expand when cultured with anti-CD3 monoclonal antibody (mAb) alone followed by a low dose of interleukin(IL)-2. In contrast, such TIL did expand efficiently in culture with both anti-CD3 mAb and LPS blasts followed by culture with IL-2. These findings suggest that the presence of LPS blasts in the initial culture was essential for the cell expansion. The expansion of TIL was partially blocked by the addition of CTLA4 Ig, which is an inhibitor of costimulatory molecules such as CD80 and CD86, and was almost blocked by the addition of anti-(Fc receptor gamma II)mAb. These findings thus indicate that such molecules, in conjunction with the receptor on the LPS blasts, participate in the efficient expansion of TIL. The B16-derived TIL, which expanded in our culture system, were predominantly CD8+ T cells and showed a higher level of cytolytic activity against B16 melanoma than either lymphokine-activated killer cells or TIL cultured with a high dose of IL-2. In addition, the in vitro expanded B16-derived TIL produced interferon gamma, but not IL-4, in response to B16 melanoma. What is more important, the adoptive transfer of such TIL had a significant antitumor effect against pulmonary metastasis in B16 melanoma, even without the concurrent administration of IL-2. Collectively, our results thus indicate the therapeutic efficacy of the protocol presented here for antitumor immunotherapy with TIL.

DISSIMILAR TCR V-BETA FREQUENCIES IN TIL FROM DIFFERENT SITES OF THE SAME TUMOR

Tumor infiltrating lymphocytes (TIL) cultured long term in media containing IL-2 were shown to mediate in vitro and in vivo anti-tumor responses. To understand the anti-tumor activity of TIL T cells, we used polymerase chain reaction (PCR) to characterize the TCR Vbeta repertoire of ovarian TIL which were isolated from three tumor sites of the same patient at the same time and cultured under identical conditions, resulting in CD3+ cells with similar CD8:CD4 ratios. TIL isolated from ovary and ascites expressed a broad distribution of Vbeta repertoire, while the Vbeta phenotype of the TIL from a secondary tumor (omentum) was more restricted. After 5 months, cultured TIL from the primary tumor (ovary) maintained a diverse TCR Vbeta repertoire, but the Vbeta phenotype of TIL from the secondary site was dominated by the Vbeta-1, -11 and -14 families. Importantly, the percentages of Vbeta-11 and Vbeta-1 expression in both omentum and ovary TIL at 3 and 5 months was found to correlate with the levels of lysis of the tumor localized to omentum (p =0.003 and p=0.014, respectively). No statistical correlation was found between cytotoxicity and the use of any other individual Vbeta families or the sum of any other families, including TCR Vbeta-3 or -20 found increased at certain time points. This suggests that where certain TCR Vbeta families are selected in tumor reactive T cells this selection may reflect tumor Ag recognition at either primary or distant tumor sites. To our knowledge, this is the first documentation of complete TCR Vbeta repertoire of ovarian TIL and of a correlation between Vbeta usage and tumor lysis, by effectors from different sites.

Regulatory effects of interleukin-4 on tumor-infiltrating lymphocytes derived from human renal cell carcinoma

We have studied the effects of interleukin-4 (IL-4) on the expansion, proliferation, phenotype, and antitumor activity of tumor-infiltrating lymphocytes (TIL) derived from human renal cell carcinoma. Cultures were obtained from three primary renal tumors and one group of tumor-invaded, regional lymph nodes. IL-4 induced a significant increase in lymphocyte expansion and proliferation, but the response was dependent on the concurrent dose of IL-2 in culture. Increased growth activity was only observed in those cultures receiving low doses (20 U/ml) of IL-2 (average increase of fold expansion of 6.5, P < 0.01) with no changes in growth activity in the high dose (1000 U/ml) cultures. The combination of low dose IL-2 and IL-4 (200 U/ml) promoted lymphocyte growth significantly better than high dose IL-2 alone, the current standard growth regimen for in vitro expansion of TIL. TIL grown in the presence of IL-4 significantly reduced the level of nonspecific, non-major histocompatibility complex-restricted antitumor activity ( P < 0.01 for allogeneic renal, nonrenal, and NK-sensitive K562 cells), while exhibiting no effect on the level of autologous killing. This is in contrast to previous findings of significant enhancement of autologous antitumor activity using IL-4 on tumor-specific, melanoma-derived TIL. We also evaluated the effects of irradiated autologous tumor stimulation (TIL:tumor ratio, 10:1) on TIL cultures. Addition of autologous tumor cells increased expansion and proliferation of all cultures regardless of concurrent lymphokines present in the culture media (average increase fold expansion of 2.21, P < 0.05). In addition, significantly enhanced levels of autologous killing were observed in some cultures after the addition of autologous tumor cells (3.4 and 5.9 lytic units without and with autologous tumor stimulation, respectively, P < 0.02). Therefore, the greatest total fold expansion was seen in those cultures containing the combination of IL-4, low dose IL-2, and irradiated autologous tumor cells, which when compared to the standard TIL growth condition of 1000 U/ml of IL-2 alone exhibited a 5.22 ± 2.44 greater fold expansion. Our results suggest that IL-4 and autologous tumor stimulation are effective growth factors, when used in combination with a low dose IL-2 regimen, and may be of significant benefit for growing activated TIL from patients with renal cell carcinoma (RCC). Furthermore, the different biologic properties and responses to exogenous lymphokines of TIL derived from RCC versus other histologically distinct neoplasms suggests the need for an individualized approach in determining the optimal regimen for the expansion and activation of these cells.

Effects of recombinant monokines (IL-1α, IL-β, TNF α) on the tissue distribution and antitumor activity of tumor-infiltrating lymphocytes (TILS) activated by IL-2: Xuelao Cao, Xiantao Kong, Tianxing Ye, Sikun Yang, Zhigong Xu. Dept of Immunol, Second Military Medical University, Shanghai 200433, P.R. China

Effects of recombinant monokines (IL-1α, IL-β, TNF α) on the tissue distribution and antitumor activity of tumor-infiltrating lymphocytes (TILS) activated by IL-2: Xuelao Cao, Xiantao Kong, Tianxing Ye, Sikun Yang, Zhigong Xu. Dept of Immunol, Second Military Medical University, Shanghai 200433, P.R. China

In vitro antitumor activity of tumor-infiltrating lymphocytes from human gastric carcinoma

Tumor-infiltrating lymphocytes (TIL) isolated from 11 gastric carcinoma were studied. TIL could grow for a long-term in medium containing recombinant interleukin-2(rIL-2). The mean expansion fold achieved in 6 long-term cultures of 11 specimens was 15.1 RIL-2 expanded gastric TIL exhibited significant cytotoxicity against K562, BGC823, MCF-7 and more effective antitumor cytotoxicity against fresh autologous tumor targets and human gastric cancer cell line. Peak cytotoxicity was shown in the third or fourth week after cultures. Cryopreservation of gastric TIL didn’t influence their expansion capacity and antitumor activity. Phenotypic analysis was demonstrated in this study. The results of present study indicate that TIL from human gastric carcinoma could be expanded and reach high levels of antitumor effector function in long-term cultures with rIL-2. Their function may be of clinical importance.

Effects of Murine Tumor Class I Major Histocompatibility Complex Expression on Antitumor Activity of Tumor-Infiltrating Lymphocytes

Tumor-infiltrating lymphocytes (TILs) are T cells that can be grown from enzyme-digested murine or human tumors. When adoptively transferred to tumor-bearing hosts concurrent with the administration of recombinant interleukin-2 (rIL-2), TILs can mediate significant regression of tumor. To examine whether expression of class I major histocompatibility complex on tumor cells influenced the generation and antitumor activity of TILs, we used clones of murine B16BL6 melanoma either transfected with or lacking the class I gene Kb to generate TILs at a high dose (1,000 U/mL) or at a low dose (20 U/mL) of human rIL-2. TILs grew from both tumors in high-dose rIL-2, but they grew from the class I-expressing tumor only in low-dose rIL-2. TILs from the class I-deficient tumor did not lyse any target tested in vitro, nor did they demonstrate any therapeutic effect in vivo on established tumors that lacked or expressed class I. In contrast, TILs from the class I-expressing tumor specifically lysed the tumor of origin in vitro and caused it to regress in vivo. Further, these TILs demonstrated activity in vitro against the non-class I-expressing melanoma treated with the combination of murine recombinant interferon gamma and human recombinant tumor necrosis factor alpha; in vivo, when administered with recombinant interferon gamma and recombinant tumor necrosis factor alpha, TILs from the class I-expressing tumor mediated regression of non-class I-expressing pulmonary metastases, presumably by augmenting class I expression.

Synergistic antitumor activity of tumor-infiltrating lymphocytes, interleukin 2, and local tumor irradiation. Studies on the mechanism of action.

The adoptive transfer of tumor-infiltrating lymphocytes (TIL) with the concomitant administration of IL-2 has been shown to mediate the regression of established 6- and 14-d murine hepatic and pulmonary metastases. For successful immunotherapy with TIL, however, pretreatment with either cyclophosphamide (CP) or whole body irradiation (WBX) was required. The exact mechanism of CP and WBX augmentation of TIL antitumor activity remains unknown, but the elimination of Ts cells has been frequently invoked as an explanation. To address this possibility and to determine if local tumor irradiation (LTX) could synergize with TIL as well as WBX, we investigated the effect of LTX on the therapeutic efficacy of TIL and IL-2 in the treatment of multiple 7-d murine hepatic metastases. Experiments studying the treatment of a weakly immunogenic murine adenocarcinoma, MC-38, showed prolonged survival of mice treated with the combination of IL-2, TIL, and either LTX or WBX, compared with treatment with radiation alone or radiation plus IL-2 controls (p less than 0.0001). In addition, therapy with LTX and IL-2 prolonged survival, compared with LTX administration alone, whereas therapy with WBX combined with IL-2 did not alter survival. This augmentation of TIL-mediated antitumor activity was dependent on the dose of radiation used. To assess the possibility that tumor-associated Ts cells inhibit the function of adoptively transferred TIL in animals with 7-d metastatic tumor and are eliminated by WBX and LTX, we repeated the above experiments leaving some tumor unirradiated. Mice underwent either LTX or limited LTX, which included only the right side of the liver (LTX1/2). The number of right- and left-sided metastases were then individually counted. These studies showed that the reduction in the number of right-sided metastases was identical between the two groups and that the presence of left-sided tumor in the LTX1/2 group did not suppress the observed antitumor activity of TIL against irradiated tumor. Additional evidence against the elimination of suppressor cells as an important mechanism in radiation-induced augmentation of TIL antitumor activity was provided by experiments studying the effectiveness of TIL in thymectomized, lethally irradiated, and reconstituted B mice. Unless CP was administered before the adoptive transfer of TIL, therapy with IL-2 and TIL in these B mice was ineffective in the absence of demonstrable T lymphocytes.(ABSTRACT TRUNCATED AT 400 WORDS)