Proliferation Of Tumor-infiltrating Lymphocytes Research Articles

Effect of hypoxia-induced mIL15 expression on expansion and memory progenitor stem-like TILs in vitro.

The adoptive cell transfer of tumor-infiltrating lymphocytes (TILs) has proven clinically beneficial in patients with non-small cell lung cancer refractory to checkpoint blockade immunotherapy, which has prompted interest in TIL-adoptive cell transfer. The transgenic expression of IL15 can promote the expansion, survival, and function of T cells ex vivo and in vivo and enhance their anti-tumor activity. The effect of expressing mIL15 regulated by hypoxia in the tumor microenvironment on the expansion, survival, and stem-like properties of TILs has not been explored. Using TILs expanded from the tumor tissues of lung cancer patients, TILs with or without mIL15 expression (TIL-mIL15 or UN-TIL) were generated by lentiviral transduction. To reflect the advantages of mTIL15, the cells were divided into groups with IL2 (TIL-mIL15+IL2) or without IL2 (TIL-mIL15-IL2). Compared to UN-TIL cells, mIL15 expression had a similar capacity for promoting TIL proliferation and maintaining cell viability. Our experimental findings indicate that, compared to UN-TIL and TIL-mIL15+IL2 cells, the expression of mIL15 in TIL-mIL15-IL2 cells promoted the formation of stem-like TILs (CD8+CD39-CD69-) and led to significant decreases in the proportion and absolute number of terminally differentiated TILs (CD8+CD39+CD69+). RNA-Seq data revealed that in TIL-mIL15-IL2 cells, the expression of genes related to T cell differentiation and effector function, including PRDM1, ID2, EOMES, IFNG, GZMB, and TNF, were significantly decreased, whereas the expression of the memory stem-like T cell marker TCF7 was significantly increased. Furthermore, compared to UN-TIL and TIL-mIL15+IL2 cells, TIL-mIL15-IL2 cells showed significantly lower expression levels of inhibitory receptors LAG3, TIGIT, and TIM3, which was consistent with the RNA-Seq results. This study demonstrates the superior persistence of TIL-mIL15-IL2 cells, which may serve as a novel treatment strategy for lung cancer patients.

Abstract 4062: The discovery and development of a CRISPR/Cas9-engineered tumor-infiltrating lymphocytes product (GT316) as a next-generation TIL therapy

Abstract Adoptive cell therapy by tumor-infiltrating lymphocytes (TILs) has demonstrated promising therapeutic effects in multiple types of solid tumors and significantly prolonged the survival of late-stage patients. However, the “prone-to-exhaustion” phenotype of the final TIL product after rapid expansion during manufacture and the presence of various immunosuppressive mechanisms in tumor microenvironment (TME) compromises the persistence and anti-tumor efficacy of TIL post infusion. To discover potential immunoregulatory targets that could maximize the function of TIL, we established a genome-wide CRISPR/Cas9 screening platform, ImmuT Finder®, to unbiasedly identify functional gene targets in primary T cells. Notably, this platform employed T cells bearing a tumor-antigen specific TCR-T that were repeatedly stimulated by tumor cells with cognate tumor antigen and demonstrated similar exhaustion profile as TIL. We selected top 30 targets after several rounds of screening and quickly validated their function in a 96-well array. Then, the top targets that showed significantly enhancement in proliferation and function of TCR-T were further selected, and their combinational effects on TIL were tested both in vitro and in vivo. Finally, double KO of GT304 and GT312 (GT316) stands out as the most potent combination, which significantly improves TIL proliferation and cytokine release, eradicates tumor growth in both CDX and PDX mouse models and promotes long-term in vivo persistence with low-dependence on IL-2. Specific and potent sgRNAs targeting both targets have been selected, and manufacturing process of GT316 TIL product has been developed (KOReTIL®). In summary, these data demonstrated that our ImmuT Finder® platform enables unbiased discovery of potent and novel targets for the development of T cell therapy and support the clinical assessment of GT316 as a next-generation TIL therapy. Currently, an investigator-initiated trial of GT316 is ongoing in China. Citation Format: Yarong Liu, Jingwei Sun, Yao Sheng, Jingman Wang, Jiahui Jin, Fei Li, Lingyun Chen, Di Zhou, Yongchao Tan, Quanwei Wang, Zhao Xu, Haibao Li, Pin Wang, Jun Cui. The discovery and development of a CRISPR/Cas9-engineered tumor-infiltrating lymphocytes product (GT316) as a next-generation TIL therapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4062.

Modulating the proliferative and cytotoxic properties of patient-derived TIL by a synthetic immune niche of immobilized CCL21 and ICAM1.

A major challenge in developing an effective adoptive cancer immunotherapy is the ex-vivo generation of tumor-reactive cells in sufficient numbers and with enhanced cytotoxic potential. It was recently demonstrated that culturing of activated murine CD8+ T-cells on a "Synthetic Immune Niche" (SIN), consisting of immobilized CCL21 and ICAM-1, enhances T-cell expansion, increases their cytotoxicity against cultured cancer cells and suppresses tumor growth in vivo. In the study reported here, we have tested the effect of the CCL21+ICAM1 SIN, on the expansion and cytotoxic phenotype of Tumor Infiltrating Lymphocytes (TIL) from melanoma patients, following activation with immobilized anti-CD3/CD28 stimulation, or commercial activation beads. The majority of TIL tested, displayed higher expansion when cultured on the coated SIN compared to cells incubated on uncoated substrate and a lower frequency of TIM-3+CD8+ cells after stimulation with anti-CD3/CD28 beads. Comparable enhancement of TIL proliferation was obtained by the CCL21+ICAM1 SIN, in a clinical setting that included a 14-day rapid expansion procedure (REP). Co-incubation of post-REP TIL with matching target cancerous cells demonstrated increased IFNγ secretion beyond baseline in most of the TIL cultures, as well as a significant increase in granzyme B levels following activation on SIN. The SIN did not significantly alter the relative frequency of CD8/CD4 populations, as well as the expression of CD28, CD25, several exhaustion markers and the differentiation status of the expanded cells. These results demonstrate the potential capacity of the CCL21+ICAM1 SIN to reinforce TIL-based immunotherapy for cancer patients.

An engineered concealed IL-15-R elicits tumor-specific CD8+T cell responses through PD-1-cis delivery.

Checkpoint blockade immunotherapy releases the inhibition of tumor-infiltrating lymphocytes (TILs) but weakly induces TIL proliferation. Exogenous IL-15 could further expand TILs and thus synergize with αPD-L1 therapy. However, systemic delivery of IL-15 extensively expands peripheral NK cells, causing severe toxicity. To redirect IL-15 to intratumoral PD-1+CD8+T effector cells instead of NK cells for better tumor control and lower toxicity, we engineered an anti-PD-1 fusion with IL-15-IL-15Rα, whose activity was geographically concealed by immunoglobulin Fc region with an engineered linker (αPD-1-IL-15-R) to bypass systemic NK cells. Systematic administration of αPD-1-IL-15-R elicited extraordinary antitumor efficacy with undetectable toxicity. Mechanistically, cis-delivery of αPD-1-IL-15-R vastly expands tumor-specific CD8+T cells for tumor rejection. Additionally, αPD-1-IL-15-R upregulated PD-1 and IL-15Rβ on T cells to create a feedforward activation loop, thus rejuvenating TILs, not only resulting in tumor control in situ, but also suppressing tumor metastasis. Collectively, renavigating IL-15 to tumor-specific PD-1+CD8+T cells, αPD-1-IL-15-R elicits effective systemic antitumor immunity.

Abstract 575: Ex vivo expansion of tumor infiltrating lymphocytes (TIL) from human renal cell carcinoma (RCC) tumors

Abstract In this study, we evaluated the feasibility of expanding tumor infiltrating lymphocytes (TIL) from surgically resected renal cell carcinoma (RCC) tumors. Tumors were collected from 43 patients undergoing surgery to remove primary kidney tumors. Tumor types included clear cell RCC (86.0%), papillary RCC (11.6%) as well as chromophobe RCC (2.3%). Tumors were minced into fragments, placed in individual wells of a 24-well plate containing media with high dose IL-2 (6000 IU/mL), and cultured for four weeks. Successful expansion was considered when at least one fragment expanded to a minimum of 2 wells. Successfully expanded TIL were then evaluated for T-cell phenotypes as well as reactivity to the autologous tumor. Of all RCC tumors collected, TIL were successfully grown for 79% of the samples (34/43). The T-cell phenotype of these TIL was highly variable across samples, although there was a higher percentage of CD4+ T-cells relative to CD8+ T-cells. The reactivity of expanded TIL was then assessed by IFNγ release. We found that TIL secreted IFNγ in response to autologous tumor in 71% of the samples. Together, these results demonstrated the feasibility of expanding functional tumor reactive TIL from RCC. Given that hypoxia plays an important role in the development of RCC tumors and is associated with poor prognosis, we then evaluated the ability to expand TIL under hypoxic conditions. To this end, primary TIL were cultured at various O2 levels (20% O2, 5% O2 or 1% O2) and the cell yield as well as the T-cell memory phenotypes were evaluated. We found that the yield of TIL grown in hypoxic conditions was lower when compared to normoxic conditions (20% O2), suggesting a reduction of TIL proliferation in hypoxia. TIL grown in hypoxic conditions displayed increased percentage of central memory T-cells compared to TIL cultured at 20% O2, as evaluated by CD45RA and CCR7 expression (CD45RA-CCR7+). Primary TIL were then expanded to larger numbers using a rapid expansion protocol (REP) by stimulation with anti-CD3 antibody in the presence of allogenic feeder cells. REP of TIL was carried out at either atmospheric O2 (20% O2) or at a hypoxic O2 level (5% O2), and the T-cell phenotype as well as reactivity to the autologous tumor were assessed. Unlike pre-REP TIL, TIL that underwent REP were able to expand in hypoxic conditions (5% O2) and displayed increased percentage of tissue resident memory T-cells (CD69+CD103+; 19%) when compared to the starting TIL population (0.11%) or TIL expanded at atmospheric O2 (0.17%). When co-cultured with the autologous tumor, hypoxic TILs displayed increased IFNγ, TNFα as well as increased Granzyme B release (p<0.001) when compared to TIL expanded in normoxia (20% O2). Collectively, these results support the advantage of adapting TIL to hypoxic conditions in the production of tumor-reactive TIL. Citation Format: Mohammed Alkhouli, Veronica Martinez-Brockhus, Matthew S. Beatty, Robert J. Gillies, Shari Pilon-Thomas, Jad Chahoud. Ex vivo expansion of tumor infiltrating lymphocytes (TIL) from human renal cell carcinoma (RCC) tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 575.

Immune Checkpoint Inhibitor-induced Reinvigoration of Tumor-infiltrating CD8+ T Cells is Determined by Their Differentiation Status in Glioblastoma.

Immune checkpoint inhibitors (ICI) are used for the treatment of various cancers, but clinical trials of anti-programmed cell death protein 1 (PD-1) with patients with recurrent glioblastoma (GBM) have failed to show clinical benefits. In this study, we examined the differentiation status of CD8+ tumor-infiltrating lymphocytes (TIL) from patients with primary GBM and their reinvigoration by ICIs to understand the nature of T-cell exhaustion in GBM. We isolated TILs from 98 patients with newly diagnosed GBM and examined the expression of immune checkpoint receptors and T-cell transcription factors using flow cytometry. TILs were ex vivo stimulated with anti-CD3 in the presence of anti-PD-1 and/or anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) and their proliferation assessed. CD8+ TILs had significantly increased expression of immune checkpoint receptors, including PD-1 and CTLA-4, compared with peripheral blood CD8+ T cells. Among CD8+ TILs, PD-1+ cells exhibited more terminally differentiated phenotypes (i.e., EomeshiT-betlo) than PD-1- cells. These data were confirmed by analyzing NY-ESO-1157-specific CD8+ TILs. Evaluating the proliferation of CD8+ TILs after ex vivo stimulation with anti-CD3 and anti-PD-1, we found that proliferation inversely correlated with the percentage of EomeshiT-betlo cells among PD-1+CD8+ TILs. When anti-CTLA-4 was used in combination with anti-PD-1, an additional increase in CD8+ TIL proliferation was observed in patients with low percentages of EomeshiT-betlo CD8+ TILs, who responded well to anti-PD-1 in ex vivo assays, but not in patients with high percentages of EomeshiT-betlo CD8+ TILs, who did not respond to anti-PD-1. In primary GBM, the differentiation status of CD8+ TILs determines their reinvigoration ability upon ICI treatment.

Blocking Tim-3 or/and PD-1 reverses dysfunction of tumor-infiltrating lymphocytes in HBV-related hepatocellular carcinoma

The immunosuppression of tumor-infiltrating lymphocytes (TILs) is associated with rapid progression of hepatitis B virus-related hepatocellular carcinoma (HBV-HCC). T cell Ig- and mucin-domain-containing molecule-3 (Tim-3) and programmed cell death 1 (PD-1) are important inhibitory molecules expressed on the surface of T cells, but their roles in the function of TILs in HBV-HCC are poorly understood. We aimed to study the roles of these two markers in HBV-HCC. Ninety patients with pathologically confirmed HBV-associated HCC were enrolled in our study. Blood samples, paired fresh tumor tissues and adjacent tissues were collected, and isolating peripheral blood mononuclear cells, TILs and adjacent-infiltrating lymphocytes were isolated from these samples. The patients were followed-up to allow survival analysis. Tim-3 or/and PD-1 was up-regulated expressed on CD4+ and CD8+ TILs in HBV-HCC patients and a higher proportion of TILs expressed PD-1 alone. Tim-3+ and PD-1+ TILs greatly decreased secretion of IFN-? and TNF-a. Expression of Tim-3 and PD-1 on TILs negatively correlated with disease-free survival of HCC patients. Direct blockade of Tim-3 and PD-1 in vitro significantly enhanced TILs proliferation and secretion of IFN-? and TNF-a. Expression of Tim-3 and/or PD-1 on TILs impairs their function and correlates negatively with disease-free survival in HBV-HCC. Direct blockade of Tim-3 and PD-1 restores anti-tumor effects of TILs, which suggests a potential target for novel immunotherapy in HBV-HCC.

Abstract 5626: Investigation of T cell activation by anti-human PD-1 antibodies Nivolumab, Pembrolizumab and BGB-A317 using tumor-infiltrating lymphocytes (TILs) from colorectal cancer and colorectal liver metastasis patients

Abstract Blockade of the PD-1 pathway with anti-PD-1 antibody, such as nivolumab (nivo) and pembrolizumab (pembro), has led to remarkable clinical responses in patients with many different cancer types. In this study, we investigated the activation of tumor-infiltrating lymphocytes (TILs) from patients with colorectal cancer (CRC) and colorectal liver metastasis (CLM) by nivo, pembro and BGB-A317, a novel humanized IgG4 anti-PD-1 antibody under clinical development. BGB-A317 has a unique binding signature to PD-1 with high affinity. Additionally, it is engineered to remove Fc gamma receptor (FcγR) binding, including FcγRI, FcγRIIA, FcγRIIB and FcγRIIIA. In our studies, all three anti-PD-1 antibodies showed significant increases in IFN-γ and TILs proliferation in a 3D tumor spheroid model. In both CRC and CLM patients, BGB-A317 treatment at concentration levels of 0.1, 1 and 10 μg/mL led to higher IFN-γ production than that in nivo and pembro treated groups. The enhanced TILs function was associated with a high density of CD8+ T cells, but inversely correlated with the percentage of CD11b+ myeloid cells in CRC tumors. Of interest, BGB-A317 showed better activation of TILs in the liver metastasis tumor microenvironment (TME) where macrophages were more abundant. This observation is consistent with the hypothesis that removal of FcγR binding might offer advantage to PD-1 mAbs in tumor microenvironment enriched with macrophages. Citation Format: Lusong Luo, Xiaoran Wu, Tong Zhang, Chunyan Fu, Yanjuan Zhang, Amy Guo, Dongping Zhou, Lianhai Zhang, Kun Wang, Baocai Xing, Jiafu Ji, Lai Wang, Kang Li. Investigation of T cell activation by anti-human PD-1 antibodies Nivolumab, Pembrolizumab and BGB-A317 using tumor-infiltrating lymphocytes (TILs) from colorectal cancer and colorectal liver metastasis patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5626. doi:10.1158/1538-7445.AM2017-5626

Costimulatory effect of agonistic 4-1BB antibody on proliferation and effector phenotype of tumor-infiltrating lymphocytes in melanoma.

2511 Background: Adoptive cell therapy with tumor-infiltrating lymphocytes (TIL) is a promising form of immunotherapy with a 20-30% durable response rate. Its widespread implementation is limited by the relatively long time needed to establish TIL in vitro and the lack of effective tumor reactivity. Our objective was to incorporate co-stimulation with 4-1BB agonism to optimize TIL growth preparation time and tumor reactivity to improve outcomes. Methods: 7 metastatic melanoma patients were consented to an IRB-approved tissue procurement protocol. For each specimen, TIL were propagated in vitro from 4 melanoma tumor fragments per condition with standard 6000 IU/mL of IL-2 and either 10 ug/mL of 4-1BB agonistic antibody (BMS-663513) or its isotype control. After 3 weeks, TIL were counted and phenotyped using flow cytometry. TIL were re-stimulated with HLA-matched melanomas and assessed for interferon-γ (IFNγ) release by ELISA. Statistical comparisons involved the 2-tailed, paired t test using GraphPad Prism software. Results: 4-1BB treatment yielded a median 4.3x107 TIL (range 1.1x107-8.4x107) compared to a median 2.3x107 cells in the control (range 1.5x106-5.3x107, p = 0.009). This is clinically significant as the initial minimum target number for TIL generation is 3x107. On phenotypic analysis compared to control, 4-1BB treatment resulted in a 1.5X higher CD8+ cell numbers (p=0.02), a 6X lower CD4+ cell numbers (p=0.02), and 5.5X lower CD4+CD25+FoxP3+ Treg cell numbers (p=0.09). A paired sample was re-stimulated in triplicate with HLA-matched tumor target, and ELISA of the supernatant treated with 4-1BB yielded 1.6 fold higher IFNγ (p=0.05). A paired sample was then assayed for known markers of T cell cytolytic activity: EOMES and perforin. 4-1BB treatment resulted in 34.5% EOMES and perforin double positive TIL compared to 18.8% in the control group. Conclusions: 4-1BB agonism is associated with enhanced kinetics of TIL proliferation, increased yield of CD8+ TIL, lower Treg numbers, increased markers of cytolysis, and enhanced IFNγ release upon tumor re-stimulation. 4-1BB agonism may be a useful adjuvant in the generation of TIL in future clinical trials.

MART-1–Specific Melanoma Tumor-Infiltrating Lymphocytes Maintaining CD28 Expression Have Improved Survival and Expansion Capability Following Antigenic Restimulation In Vitro

We determined how CD8(+) melanoma tumor-infiltrating lymphocytes (TILs) isolated from two distinct phases of expansion in preparation for adoptive T cell therapy respond to melanoma Ag restimulation. We found that TILs isolated after the rapid expansion protocol (REP) phase, used to generate the final patient TIL infusion product, were hyporesponsive to restimulation with MART-1 peptide-pulsed dendritic cells, with many CD8(+) T cells undergoing apoptosis. Telomere length was shorter post-REP, but of sufficient length to support further cell division. Phenotypic analysis revealed that cell-surface CD28 expression was significantly reduced in post-REP TILs, whereas CD27 levels remained unchanged. Tracking post-REP TIL proliferation by CFSE dilution, as well as sorting for CD8(+)CD28(+) and CD8(+)CD28(-) post-REP subsets, revealed that the few CD28(+) TILs remaining post-REP had superior survival capacity and proliferated after restimulation with MART-1 peptide. An analysis of different supportive cytokine mixtures during the REP found that a combination of IL-15 and IL-21 facilitated comparable expansion of CD8(+) TILs as IL-2, but prevented the loss of CD28 expression with improved responsiveness to antigenic restimulation post-REP. These results suggest that current expansion protocols using IL-2 for melanoma adoptive T cell therapy yields largely CD8(+) T cells unable to persist and divide in vivo following Ag contact. The few CD8(+)CD28(+) T cells that remain may be the only CD8(+) TILs that ultimately survive to repopulate the host and mediate long-term tumor control. A REP protocol using IL-15 and IL-21 may greatly increase the number of CD28(+) TILs capable of long-term persistence.

Effects of auto-tumor infiltrating lymphocytes induced by interleukin (IL)-12 with IL-2 on patients of primary hepatic carcinoma

To investigate the effects of the tumor infiltrating lymphocytes (TILs) from primary hepatic carcinoma (PHC) induced by interleukin-12 (IL-12) with IL-2, on their cytotoxicity, proliferation, and cytokine production, and the immunological function and survival of the PHC patients. PHC cells and TILs were isolated from the resected tumors and cultured. IL-2 was added into the culture medium with or without IL-12. Ten to 14 days later the cytotoxic activity and proliferation index (PI) of the TILs were calculated. The levels of the cytokine interferon (IFR)-gamma and tumor necrosis factor (TNF)-alpha in the supernatant were tested by ELISA. 20-25 days after the operation the TILs were re-infused into the bodies. The clinical manifestation, cytotoxicity of TILs, phenotype of peripheral blood lymphocytes, and survival of patients were observed. 1. The cytotoxicity of the TILs of the IL-12 + IL-2 group against the autologous hepatic carcinoma cells was greater than that of the TILs of the IL-2 group (P < 0.05). 2. The PI of the TILs of the IL-12 + IL-2 group was 17.78%, significantly higher than that of the IL-2 group (10.9%, P < 0. 05). 3. The levels of IFN-gamma and TNF-alpha of the IL-12 + IL-2 group were (2180 +/- 494) pg/ml and(485 +/- 98) pg/ml, both significantly higher than those of the IL-2 group [(1078 +/- 309.46) pg/ml and (422.00 +/- 15.81) pg/ml, both P < 0. 05]. 4. After re-infusion of TILs, the CD3+, CD8+, CD4+, and CD56+ rates, especially the CD3+ and CD8+ rates, of the IL-12 + IL-2 group were all significantly higher than those of the IL-2 group (all P < 0.05). 5. After TIL re-infusion the clinical manifestation of all patients were improved. 6. 23 of the 25 patients receiving the re-infusion of the TILs of the IL-12 + IL-2 group survived for more than 1 year, with a rate significantly higher than that of the IL-2 group (17/25, chi2 = 4.5, P < 0.05), however, there were no significant differences in the 3-year and 5-year survival rates between these 2 groups (both P > 0.05). The number of patients who showed recurrence in less than 1 year was 17 in the IL-2 group, with a rate significantly higher that of the IL-12 + IL-2 group (8/25, chi2 = 4.32, P < 0.0 5). However, there was no significant difference in the recurrence rate < or = 3 years between these 2 groups (chi2 = 1.56, P > 0.05). TILs from primary hepatic carcinoma induced by IL-12 can obviously enhance specific cytotoxicity and proliferation of TILs. TILs induced by IL-12 + IL-2 increase the patients' immunological function, prolong the 1-year survival, and decreases recurrence more effectively than the TILs induced by IL-2 only.

Tenascin-C, over expressed in lung cancer down regulates effector functions of tumor infiltrating lymphocytes

Purpose: Extracellular matrix (ECM) proteins play a significant role in the survival and metastasis of cancer cells. Tenascin-C (TN-C) is an extracellular matrix protein and its large isoform has been implicated in tumor progression. Goal of this study was to analyze the expression of the small and large isoforms of TN-C in non-small cell lung cancer (NSCLC) and determine its functional significance. Experimental design: TN-C expression was studied in tumor and non-tumor tissue of patients with NSCLC at the mRNA and protein level. Immunomodulatory properties of the large isoform of TN-C were analyzed by determining its effect on lymphocyte proliferation and cytokine secretion by tumor-infiltrating lymphocytes (TIL). Results: Quantitative real-time PCR analysis showed an eight-fold increase in the amount of large isoform in cancer cells compared to adjacent normal tissue. Expression at the protein level by Western blot analysis using a murine monoclonal anti-TN-C antibody detected increased expression of the large isoform in the tumor tissue that was correlated with the development of recurrent disease. A 18-fold increase in the expression of the large TN-C isoform was observed in patients with recurrent NSCLC compared to non-recurrent NSCLC. Large isoform of TN-C significantly inhibited anti-CD3 and mitogen-induced proliferation of human peripheral blood lymphocytes and interferon-gamma production by TIL isolated from the lung cancer specimens. Conclusions: Increased expression of TN-C observed at the site of tumor in NSCLC correlates with recurrence. TN-C inhibits TIL proliferation and cytokine thereby may promote tumor immune evasion and recurrence.

Immune inhibitory effects of renal cell carcinoma extract on lectin and alloantigen-induced peripheral blood and tumor infiltratinglymphocyte blastogenesis

The presence of tumor infiltrating lymphocytes (TIL) has been attributed to the host cell mediated immune response against the evolving malignancy. However, due to specific evasive and escape mechanisms, the immune competent cells are rendered ineffective. One such mechanism may be the production of immune suppressor substance(s), inhibiting lymphocyte proliferation, and subsequently, their transformation into effector cells. To evaluate a possible impact of RCC extract on lectin and alloantigen-induced proliferation of TIL and peripheral blood lymphocytes (PBL) from renal cell carcinoma (RCC) patients and from healthy control human subjects. Tumor extract and TIL were derived from 13 patients with RCC undergoing radical nephrectomy. Tumor infiltrating lymphocytes and PBL from these patients were activated with Concanavalin A (Con-A), Phytohemoglutinine (PHA) or Pokeweed (PW) and the rate of blastogenesis was measured by 3H Thymidine incorporation. The same procedure was used in assay with PBL from control healthy blood donors. There was a significant reduction (88.6%) in the proliferative response to ConA of TIL compared to PBL from the same patients ( P = 0.007). A similar decrease was seen following stimulation by PHA (85.8%, P = 0.01) and PW mitogen (78.5%, P = 0.001). A 79.5% decrease in response level of TIL to alloantigens compared to PBL from RCC patients ( P = 0.021), was observed. Lectin induced proliferative response of RCC patients was significantly lower in the presence of RCC extract (82.9%) compared to normal kidney extract ( P = 0.008). Alloantigenic stimulation of healthy individual PBL was also decreased significantly in the presence of RCC extract (92.9%, P = 0.0001) compared to normal kidney extract. Similarly, lectin induced stimulation of healthy control PBL in the presence of RCC extract was significantly lower (83.2%, P = 0.003). Our data suggest that RCC extract contains an immune suppressive substance(s), capable of inhibiting lymphocyte proliferative response of tumor infiltrating lymphocytes as well as of PBL from patients and healthy individuals alike. This may be one of the mechanisms by which the tumor evades the transformation of lymphocytes into effector killer cells, and thus affects the biological inter-relationship between tumor and host. Identification of this substance and its gene may provide an effective anti-tumoral treatment modality.

Suboptimal activation of melanoma infiltrating lymphocytes (TIL) due to low avidity of TCR/MHC-tumor peptide interactions.

Coculture of melanoma cells and T cell clones derived from tumor-infiltrating lymphocytes (TIL) generally results in lysis of the antigen-bearing tumor cells but to inefficient proliferation and IL-2 secretion by responder T cells. This suboptimal activation is classically explained by an inability of tumor cells to provide costimulatory signals. Here we analyzed the responses to synthetic peptides of HLA-A2.1-restricted CTL clones specific for melanoma antigens MART-1 and NA17-A. We showed that peptide concentrations ranging from 1 pM to 10 nM efficiently sensitized the peptide transporter-deficient T2 cells to lysis. T2 cells pulsed with melanoma peptides also induced TIL proliferation and detectable secretion of IL-2, IFN-gamma and GM-CSF, but only for peptide concentrations 10- to 10,000-fold higher than those required for lysis. Hence this suggests that partial triggering of TIL clones by melanoma cells could be due to expression of appropriate MHC-peptide complexes at subthreshold levels. In support of this, we showed that melanoma cells, unable to trigger IL-2 secretion, developed this ability when incubated with the appropriate peptide. These results indicate that the level of antigens expressed on melanoma tumors critically affects TIL activation status and thus, the efficiency of specific immune reactions mediated by these cells.

Interleukin-12 augments the generation of autologous tumor-reactive CD8+ cytotoxic T lymphocytes from tumor-infiltrating lymphocytes.

Human tumor‐infiltrating lymphocytes (TIL) were obtained from breast cancer, renal cancer or neuroblastoma to investigate the generation of autologous tumor‐reactive CD8+ cytotoxic T lymphocytes (CTL). When TIL were cultured with interleukin (IL)‐2 (100 U/ml), the growth of TIL peaked around 8–10 days after the initiation of culture. In contrast, the proliferation of TIL cultured with IL‐2 plus IL‐12 peaked around 4–5 days after culture and tumor cells rapidly disappeared from the culture. To determine the generation of autologous tumor‐reactive CD8+ CTL, TIL‐derived CD8+ T cells were separated by FACStar. Both IL‐2‐activated and IL‐2 plus IL‐12‐activated TIL‐CD8+ T cells showed the same level of lymphokine‐activated killer activity against a variety of tumor cells. However, TIL‐CD8+ T cells activated with IL‐2 plus IL‐12 revealed greatly augmented cytotoxicity against autologous tumor cells compared with that induced by IL‐2 alone. The autologous tumor cell‐killing activity of TIL‐CD8+ CTL was significantly inhibited by the addition of F(ab)2 anti‐CD3 monoclonal antibody, indicating that these CTL recognize autologous tumor antigen through T cell receptor. These results imply that IL‐12 is a novel cytokine which facilitates the generation of autologous tumor‐reactive CD8+ CTL from TIL.

Enhanced interleukin-2 production in human tumor-infiltrating lymphocytes engineered by 3'-truncated interleukin-2 gene.

Tumor-infiltrating lymphocytes (TILs), T lymphocytes associated with solid tumors that can be grown with interleukin (IL)-2 in vitro, preferentially accumulate at tumor sites after adoptive transfer. Therefore, TILs can be considered for use as cellular vehicles in gene therapy. We transduced melanoma TILs with the IL-2 gene and clarified functional characteristics of the TIL transductants. TILs transduced with 3'-end-truncated IL-2 gene (480 bp) produced high amounts of IL-2 detected in supernatants when compared to TILs transduced with the native IL-2 gene containing 3'-end adenine-thymidine (AT)-rich sequences (650 bp). The level of IL-2 in supernatants was higher with the addition of anti-Tac antibody (Ab) to block the consumption of IL-2 by the TILs. These TILs could proliferate autonomously in the absence of exogenous IL-2, and the proliferation of TILs could be completely blocked by anti-IL-2 Ab or anti-IL-2 receptor Ab. Thus TILs transduced with IL-2 gene can proliferate through the autocrine loop. However, the expression of IL-2 from TILs transduced with the IL-2 gene was downregulated after 2 to 3 weeks of G418 selection. Our study indicates the feasibility of transduction and expression of a truncated 480-bp IL-2 gene into TILs and the possibility of employing adoptive immunotherapy protocols using TILs modified with this IL-2 gene.

Interleukin-2 Expanded Tumor-Infiltrating Lymphocytes and their Response to Preoperative α-Interferon in Patients with Renal Cell Carcinoma

To determine whether interferon-α could augment antitumorigenic effect of the tumor-infiltrating lymphocytes expanded with interleukin-2, we evaluated the properties of interleukin-2 expanded tumor-infiltrating lymphocytes in 24 patients with renal cell carcinoma with or without treatment with interferon-α. Tumor-infiltrating lymphocytes containing tumor cells were separated from nephrectomy specimens by enzymatic digestion and Percoll gradient centrifugation, and were cultured in the serum-free medium containing interleukin-2. The number of lymphocytes increased by 10 to 1,000-fold by day 28 of culture. There was no difference in the proliferation of tumor-infiltrating lymphocytes between interferon-α treated patients and controls. On day 14 tumor-infiltrating lymphocytes in the treated patients contained significantly more activated cells (HLA-DR+) and suppressor T cells (CD8+11+) than those in the controls. No significant difference was noted, however, in the cytotoxicity of tumor-infiltrating lymphocytes against autologous and allogenic renal cell carcinoma, K-562 or Daudi cells between the experimental and control groups on day 14 or 28. No specific effects on the major histocompatibility antigens, such as modulation of the expression attributable to the preoperative treatment with interferon-α, were observed on renal cell carcinoma tissue when determined by immunohisto-chemical staining. These findings suggest that interferon-α does not consistently produce a beneficial effect on interleukin-2 expanded tumor-infiltrating lymphocytes in patients with renal cell carcinoma.

Tumor-Infiltrating Lymphocytes Derived From Select B-Cell Lymphomas Secrete Granulocyte-Macrophage Colony-Stimulating Factor and Tumor Necrosis Factor-α in Response to Autologous Tumor Stimulation

Tumor infiltrating lymphocytes (TIL) were cultured from 17 B-cell lymphoma specimens derived from patients with predominantly low-grade malignancies. Specimens included 15 lymph-node biopsies, 1 malignant pleural effusion, and PBL from 1 patient with circulating lymphoma cells. The phenotypic and proliferative characteristics of TIL cultured in interleukin-2 (IL-2) were studied, as well as cytolysis and cytokine secretion in response to autologous tumor. Flow cytometry of fresh tumor suspensions showed that 50% of cells (median) were malignant B cells and 36% were infiltrating T lymphocytes. After culture for approximately 1 month, TIL were 75% +/- 8% CD3+ (mean +/- SEM), 47% +/- 8% CD4+ and 35% +/- 7% CD8+. TIL proliferation was modest in most cases: the median maximum expansion was 32-fold in 25 days. Lysis of autologous tumor in 4-hour 51Cr release assays was mediated by 2 of 12 TIL studied, but was nonspecific. However, these same two TIL, when cocultured with various tumor stimulators, preferentially secreted tumor necrosis factor-alpha and granulocyte-macrophage colony-stimulating factor after autologous tumor stimulation; unstimulated TIL secreted undetectable or barely detectable levels of these cytokines. In one TIL culture, cytokines were secreted by purified CD4+ TIL but not by CD8+ cells, and secretion was completely abrogated by the anti-major histocompatibility complex (MHC) class II antibody IVA12. Thus, although specific cytokine secretion by lymphoma TIL in response to autologous tumor was observed, it occurred in fewer than 20% of patients studied.

Tumor-infiltrating lymphocytes derived from select B-cell lymphomas secrete granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha in response to autologous tumor stimulation

Tumor infiltrating lymphocytes (TIL) were cultured from 17 B-cell lymphoma specimens derived from patients with predominantly low-grade malignancies. Specimens included 15 lymph-node biopsies, 1 malignant pleural effusion, and PBL from 1 patient with circulating lymphoma cells. The phenotypic and proliferative characteristics of TIL cultured in interleukin-2 (IL-2) were studied, as well as cytolysis and cytokine secretion in response to autologous tumor. Flow cytometry of fresh tumor suspensions showed that 50% of cells (median) were malignant B cells and 36% were infiltrating T lymphocytes. After culture for approximately 1 month, TIL were 75% +/- 8% CD3+ (mean +/- SEM), 47% +/- 8% CD4+ and 35% +/- 7% CD8+. TIL proliferation was modest in most cases: the median maximum expansion was 32-fold in 25 days. Lysis of autologous tumor in 4-hour 51Cr release assays was mediated by 2 of 12 TIL studied, but was nonspecific. However, these same two TIL, when cocultured with various tumor stimulators, preferentially secreted tumor necrosis factor-alpha and granulocyte-macrophage colony- stimulating factor after autologous tumor stimulation; unstimulated TIL secreted undetectable or barely detectable levels of these cytokines. In one TIL culture, cytokines were secreted by purified CD4+ TIL but not by CD8+ cells, and secretion was completely abrogated by the anti- major histocompatibility complex (MHC) class II antibody IVA12. Thus, although specific cytokine secretion by lymphoma TIL in response to autologous tumor was observed, it occurred in fewer than 20% of patients studied.

Pulmonary Macrophages Suppress the Proliferation and Cytotoxicity of Tumor-infiltrating Lymphocytes

Adoptive immunotherapy with interleukin-2 and tumor-infiltrating lymphocytes (TIL) is rarely effective in primary lung cancer. We hypothesize that pulmonary macrophages (PM), which are increased substantially in the lungs of smokers, might suppress TIL function. The addition of PM into the TIL cytotoxicity assay produced a concentration-dependent suppression of TIL cytotoxicity with up to 71% inhibition of autologous tumor killing at the 1:1 PM:TIL ratio. Inhibition was not target-specific, as killing of NK-sensitive (K562), NK-resistant (M14), and autologous tumor targets were equally suppressed. Nor was inhibition specific for lung TIL, as similar inhibition was observed with melanoma and renal TIL. Using a model system, we demonstrated that both CD3+ antigen-specific and CD56+ nonspecific lymphocytes are susceptible to the suppressive effects of the PM. Direct co-incubation of PM and TIL for 4 to 44 h resulted in progressive suppression of TIL proliferation and cytotoxicity. TIL cytotoxicity remained suppressed even if PM were removed from the co-culture after 24 h, but was restored if the separated TIL were re-incubated in interleukin-2. These results suggest that PM may locally regulate the proliferative and cytotoxic function of adoptively transferred TIL.