Influence of the donors' clinical status on in vitro and in vivo tumor-cytotoxic activation of interleukin-2-exposed lymphocytes and their circulation in different organs

Cytotoxic T lymphocytes recognize tumor antigens of a murine colonic carcinoma by using different T-cell receptors

To see whether different antigens expressed by the same tumor are recognized by distinct T-cell receptors (TCR), we used cytotoxic T-lymphocyte (CTL) lines known to lyse in vitro the syngeneic BALB/c adenocarcinoma C-26. Four of these CD3+ CD8+ lines showed 4 different patterns of lysis on a panel of MHC-class-I-compatible targets. The activity was H-2d-restricted and could be blocked by anti-CD3 and anti-TCR-alpha/beta monoclonal antibodies (MAbs). The CTL lines were also effective, although to a different extent, in adoptive immunotherapy of mice bearing lung metastases. Phenotypic analysis revealed in all the lines a high frequency of cells positive for CD45, asialo GM1 (ASGM1), lymphocyte-function-associated antigen-1 (LFA-1), intercellular adhesion molecule-1 (ICAM-1) and CD44, but negligible expression of L-selectin (LAM-1) and very late antigen-4 (VLA-4); 2 lines expressed the vitronectin-receptor (VN-R). Analysis of TCR V beta-chains used by the 4 lines showed selective presence of V beta 6, V beta 8.2, V beta 8.3 and of V beta 13 chains. MAbs directed to these V beta chains blocked their lytic activity in vitro. V alpha-chain transcripts of the lines were identified by polymerase chain reaction (PCR) as V alpha ITT11 and V alpha 52 in 2 lines, while one could not be identified. Analysis of V beta s in mixed lymphocyte-tumor-cell cultures (MLTC) of T cells deriving from tumor-infiltrating lymphocytes (TIL) or from spleen of C-26 tumor-bearing or immune animals indicated that the TCR of the CTL lines were representatives of the TCR repertoire recognizing C-26 tumor, since their V beta s were shown to be selectively expanded in MLTC.

Antitumour efficacy of lymphokine-activated killer cells loaded with ricin against experimentally induced lung metastases

Adoptive transfer of tumour-specific T lymphocytes loaded with ricin into tumour-bearing mice exerts a transient therapeutic effect against locally induced tumours [Cerundolo et al. (1987) Br J Cancer 55: 413]. As transferred cells preferentially locate in the lung, we studied the therapeutic effect of ricin-loaded, lymphokine-activated killer (LAK) cells on lung metastases induced by M4 or B16-F1 (F1) tumour cell injection. In vitro studies demonstrated that ricin-treated LAK cells were about 100-fold more efficient than untreated LAK cells in inhibiting growth of the ricin-sensitive M4 tumour cell line. This effect was most likely due to the released ricin, as treated and untreated LAK cells inhibited the relatively toxin-resistant F1 cell line to the same extent. Ricin treatment did not alter the tissue distribution of intravenously (i.v.) injected LAK cells, which selectively localized in the lung early after inoculation, whether or not metastases were present. Adoptive transfer experiments showed that ricin-treated LAK cells were significantly more efficient than untreated LAK cells in inhibiting M4- but not F1-induced lung metastases. These results indicate that LAK cells are able to deliver a therapeutic concentration of antineoplastic compounds directly to the lung.

Cytoreductive surgery impedes metastasis and enhances the immune response: a preliminary report

In an effort to determine the effect of cytoreductive surgery on the metastatic process, MAT-LyLu flank tumors were excised from Copenhagen x Fischer rats and the effects of this surgery on metastatic lung lesions were observed. Cytoreduction resulted in a decrease in lung lesions (P less than 0.05). Adjuvant cyclophosphamide (CTX) further enhanced this beneficial effect. A concurrent increase in the helper/suppressor ratios suggested that this beneficial response might be mediated by the host's immune response.

Thymosin alpha 1 potentiates interleukin 2-induced cytotoxic activity in mice

We have investigated the effects of interleukin 2 (IL-2) on cytotoxic activity of spleen lymphocytes, from normal and cyclophosphamide (200 mg/kg) or B-16 melanoma suppressed mice, after in vitro or in vivo pretreatment with thymosin alpha 1 (TA1). The results of this study indicate that pretreatment in vitro (100 ng/ml for 1 hr) or in vivo (200 micrograms/kg/day for 4 days) with thymosin alpha 1 (TA1), significantly increased the IL-2 (from 100 to 500 U/ml) in vitro induced cytotoxic activity of spleen lymphocytes, collected from both normal and cyclophosphamide and tumor-suppressed animals, against both YAC-1 (NK sensitive) and MBL-2 (NK resistant) cell lines. The potential use in combination of these two different biological response modifiers, useful in enhancing the immunological responses to IL-2 of lymphocytes, may provide a novel model of immunotherapeutic intervention in cancer.

Therapeutic use of a long-term cytotoxic T cell line recognizing a common tumour-associated antigen: the pattern of in vitro reactivity predicts the in vivo effect on different tumours

A long-term-cultured cytotoxic T lymphocyte (CTL) line (E/88) was obtained from splenic lymphocytes of BALB/c (H-2d) mice bearing the weakly immunogenic colonic carcinoma C26. This line was shown to be alpha/beta TCR + V beta 6 + CD3 + CD8 + CD4- and to recognize a common tumour-associated antigen on syngeneic carcinomas and sarcomas in a major-histocompatibility--complex-restricted and T-cell-receptor(TCR)-mediated fashion. The assessment of cytotoxic activity on a panel of 30 normal and neoplastic target cells of differing etiology and histo-type showed that E/88 CTL lysed syngeneic colon carcinomas and some fibrosarcomas but not leukemias, lymphomas or mammary carcinomas. Clones derived from the E/88 line exhibited the same lytic pattern. Moreover, anti-T3, anti-Lyt2.2, anti-alpha/beta TCR and anti-V beta 6 mAbs as well as anti-H-2d antisera abolished cytotoxicity when used in blocking experiments. The therapeutic activity of E/88 CTL upon in vivo transfer was assessed in mice bearing either experimental or spontaneous metastases of C26. In both models therapy with E/88 lymphocytes in combination or not with interleukin-2 was highly effective. Adoptive immunotherapy carried out with two clones obtained from line E/88 showed comparable therapeutic effects. In addition, treatment of syngeneic mice bearing experimental metastases of in vitro E/88-lysable or E/88-resistant tumours, showed that E/88 CTL can eradicate metastases of the former but not of the latter neoplasms. These data indicate that long-term CTL lines recognizing common tumour-associated antigens can be derived from tumour-bearing animals and used in adoptive immunotherapy of tumours previously shown to be lysed in vitro by these effectors.

Adoptive immunotherapy of a mouse colon carcinoma with recombinant interleukin-2 alone or combined with lymphokine-activated killer cells or tumor-immune lymphocytes. Survival benefit of adjuvant post-surgical treatments and comparison with experimental metastases model

We have used a BALB/c colonic adenocarcinoma (C-26) to evaluate the therapeutic potential of recombinant interleukin-2 (rIL-2) at high and low dosages in combination with or without lymphokine-activated killers (LAK) or tumor-specific, immune lymphocytes in either an adjuvant spontaneous or an artificial metastasis system. Most (approximately 80%) of the mice that underwent s.c. C-26 tumor excision systemic treatment with low-dose rIL-2 (3 x 10(4) U/day, i.p.) increased the survival rate to 31% as compared to 21% (not significant) in excised controls while administration of high-dose rIL-2 (8 x 10(4) U/day) led to 53% survival (P less than 0.001). Both LAK cells and C-26-tumor-immune lymphocytes given during rIL-2-treatment significantly increased the effects of rIL-2 at the low but not at the high-dose, with tumor-immune effectors resulting in the highest percentage (63%) of cures. When mice bearing 3-day artificial lung metastases of C-26 cells were treated wtih low- or high-dose rIL-2, in combination with or without LAK or tumor-immune lymphocytes, a highly significant reduction or abrogation of the number of lung foci was observed with all treatments, including those involving or tumor-immune lymphocytes alone. Assessment of survival benefit in these mice, however, showed survival prolongation, with 20% cures achieved by low-dose rIL-2 alone and up to 65% cures by LAK in combination with low-dose rIL-2. In this system of artificial metastasis high-dose rIL-2 alone increased the survival time but failed to cure the animals, and the addition of LAK was ineffective whereas that of tumor-immune lymphocytes led to 80% cure. These results suggest that tumor-immune lymphocytes are more effective than LAK when combined with rIL-2 and that caution is necessary in extrapolating findings obtained in artificial metastasis models.

Fate of intravenously administered rat lymphokine-activated killer cells labeled with different markers

Rat lymphokine-activated killer (LAK) cells, generated by adhering rat splenocytes isolated from the 52% Percoll density fraction to plastic flasks, demonstrate restricted in vivo tissue distribution, localizing in the lungs and liver after 2 h, but redistributing into the liver and spleen 24 h after i.v. administration. However, a different pattern of distribution was observed when this population of LAK cells was labeled with one of four commonly used radioisotopes. For example, LAK cells showed a high distribution into the lungs 30 min after administration when labeled with 51Cr, 125I-dUrd or 111In-oxine, whereas 111InCl-labeled LAK cells showed an equal distribution into the blood, lungs and liver at this time. Two hours after administration, cells labeled with 111In-oxine showed an equivalent distribution into the lungs and liver, those labeled with 125I-dUrd or 51Cr showed a high accumulation in the lungs, whereas those labeled with 111In-Cl entered more into the liver and blood. The pattern of distribution of 111In-Cl- or 111In-oxine-labeled cells was confirmed using gamma camera imaging analysis. By 24 h, LAK cells labeled with 111InCl, 111In-oxine or 51Cr distributed in the liver and spleen in variable concentrations. In contrast, cells labeled with 125I-dUrd were not detected in any organ tested. This study was paralleled by monitoring the distribution of LAK cells labeled with Hoechst 33342 (H33342) and analyzed for the presence of fluoresceinated cells in different organs either by flow cytometry analysis, or in frozen section. The data indicate that the distribution pattern of LAK cells labeled with 111In-oxine is the closest to the distribution of H33342-labeled cells. Of all the radioisotopes used, 125I-dUrd has the most disadvantages and is not recommended for monitoring the in vivo distribution of leukocytes.