This clinical study was based on experimental results obtained in nude mice grafted with human colon carcinoma, showing that injected 131I-labeled F(ab)2 and Fab fragments from high affinity anti-carcinoembryonic antigen (CEA) monoclonal antibodies (MAb) gave markedly higher ratios of tumor to normal tissue localization than intact MAb. 31 patients with known colorectal carcinoma, including 10 primary tumors, 13 local tumor recurrences, and 21 metastatic involvements, were injected with '13I-labeled F(ab')2 (a = 14) or Fab (a = 17) fragments from MAb anti-CEA. The patients were examined by emission-computerized tomography (ECT) at 6, 24, and sometimes 48 h after injection using a rotating dual head scintillation camera. All 23 primary tumors and local recurrences except one were clearly visualized on at least two sections of different tomographic planes. Interestingly, nine of these patients had almost normal circulating CEA levels, and three of the visualized tumors weighed only 3-5 g. Among 19 known metastatic tumor involvements, 14 were correctly localized by ECT. Two additional liver and several bone metastases were discovered by immunoscintiraphy. Altogether, 86% of the tumor sites were detected, 82% with F(ab')2 and 89% with Fab fragments. The contrast of the tumor images obtained with Fab fragments suggests that this improved method of immunoscintigraphy has the potential to detect early tumor recurrences and thus to increase the survival of patients. The results of this retrospective study, however, should be confirmed in a prospective study before this method can be recommended for the routine diagnosis of cancer.

Mononuclear cells infiltrating human brain tumors were isolated from seven of nine surgical biopsy specimens. These cells were small T11+, T3+ lymphocytes that did not express DR antigens or the receptor for interleukin-2. In addition, large granular lymphocytes were recovered from two of these tumors. The clonogenic potential of tumor-infiltrating lymphocytes (TIL's) was assessed by limiting-dilution analysis (LDA) using a microculture system that permits proliferation of virtually 100% of normal peripheral blood T lymphocytes (PBL-T's). In comparison to normal and autologous PBL-T's, TIL's had a strikingly reduced proliferative potential revealed by a decrease in the frequency of proliferating T lymphocyte precursors calculated by LDA. On average, only one of every 100 T cells from TIL's was able to proliferate, as compared to one of every two or all of the T cells from the patient's peripheral blood or from normal donors. Furthermore, the TIL populations showed depressed proliferative responses to the lectins phytohemagglutinin and concanavalin A and to the phorbol ester 12-0-tetradecanoyl-phorbol-13-acetate. Clonal analysis performed on the proliferating microcultures from three tumors demonstrated that the majority of these clones possessed cytolytic activity against various tumor cell targets. Among clones tested for cytolytic activities with glioma cells, four lysed cultured autologous tumor cells, and the specific lysis was greater than 50% in all cases. Numerous clones with natural killer (NK)-like activity were obtained from two TIL preparations, and the frequency of cytolytic T lymphocyte precursors with NK-like activity was determined for one of these preparations and was found to be higher than that in the patient's peripheral blood. Glioma cells grown in culture and then mixed with normal peripheral blood lymphocytes (PBL's) were capable of inhibiting the PBL's response to lectins. This inhibitory property may account in part for the observed poor clonogenicity of TIL's from brain tumors. Nevertheless, nearly all proliferating clones displayed cytotoxicity against either autologous or allogeneic tumor cell targets and may imply selective accumulation of cytolytic effector cells at the tumor site.

Tumor-infiltrating lymphocytes (TIL) were obtained by a combination of mechanical release and enzymatic disaggregation from 35 human solid tumors. The number of lymphocytes in TIL-enriched suspensions varied from 1 X 10(4) to 7.6 X 10(6) per wet gram of tumor. The TIL preparations separated by differential centrifugation on Ficoll-Hypaque gradients contained 10-95% of T11+ cells (mean 50%), and tumor cells accounted for the other major cellular component. Macrophages, NK cells, B cells and granulocytes were infrequently seen. Morphologically, TIL-T were small non-activated cells. They expressed the T11 and T3 antigens but not the receptor for IL-2 (IL-2R) or HLA-DR antigens as determined by double immunofluorescence staining. Rare T11+/IL-2R+ cells were recovered only from colon and lung carcinomas. The mean T4/T8 ratio in 12 TIL preparations was 1.1 +/- 0.8. Immunohistology with monoclonal antibodies (MAbs) performed in 31/35 tumors confirmed that the T11+ cells infiltrating solid tumors rarely expressed the IL-2R and that the cell content of suspensions enriched in TIL was comparable to that determined in situ. The recovered TIL were cloned in a microculture system that permits proliferation of nearly all normal peripheral blood T lymphocytes (PBL-T). Under these culture conditions, frequencies of the proliferating T lymphocyte precursors (PTL-P) were depressed in both the TIL preparations (less than 0.01 to 0.39) and patients' PBL-T (0.05 to 0.5). These low frequencies of PTL-P were seen in patients with all tumor types, both primary and metastatic.

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Nasopharyngeal carcinoma (NPC) is an epithelial tumor consistently associated with EBV. The histological picture is characterized by a strikingly abundant lymphocytic infiltrate. Furthermore, the epithelial tumor cells present several immunological characteristics which suggest an important role for tumor-infiltrating lymphocytes (TIL) in the biology of this tumor. The present study reports the phenotypic and functional characterization of TIL from NPC obtained after enzymatic digestion of 15 NPC biopsies. Flow cytometric analysis of TIL suspensions indicated that most TIL were mature CD3+ T lymphocytes (mean = 60%) with a variable CD4/CD8 ratio. Most TIL were TCR alpha/beta-positive (mean = 55%) and only a few TCR gamma-delta-positive cells could be identified. A small percentage (mean = 9%) displayed an activated phenotype (CD25+, HLA class II+). Using limiting dilution analysis, we found that the average frequency of proliferative T-lymphocyte precursors (PTL-P) is lower among TIL (1/40) than in autologous (1/7) or normal PBL (1/1.4). Moreover, sorting experiments have shown that this defect is significantly more pronounced in the CD8+ than in the CD4+ TIL subset. Accordingly, the TCR and the CD2-mediated antigen-independent pathways of activation were impaired. Different types of cytotoxic precursor could be detected. These included lectin-dependent cell cytotoxicity (LDCC) and NK-like or lymphokine-activated killer (LAK) activity. Interestingly, some TIL from NPC were able to lyse an NPC tumor (C15) maintained in nude mice. Thus, despite impaired activation pathways, the cytolytic potential of proliferating TIL in NPC is preserved.