Immune response to autologous human melanoma: implication of class I and II MHC products.
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Antibodies, Monoclonal↗
Biomedical subjects
G Parmiani
Publications and source records attributed to G Parmiani.
Control of human melanoma growth in nude mice by autologous allo-activated peripheral blood lymphocytes.
Human peripheral blood lymphocytes (PBL) were activated in vitro by means of a pool of allogeneic PBL from normal donors and then evaluated for in vivo activity against human melanoma cells xenografted in splenectomized and irradiated athymic (nude) mice. The subcutaneous (s.c.) growth of human melanoma cells was inhibited by intravenous (i.v.) injection, 2 hr later, of such allo-activated, autologous and allogeneic PBL in 7/8 and in 6/9 mice respectively. Unstimulated PBL were ineffective. When allo-activated patients' lymphocytes were administered 3 days after s.c. implantation of autologous melanoma cells, inhibition of tumor growth was observed in 1/6 mice. A significant delay in tumor appearance was noted in the remaining animals. Unstimulated as well as allo-activated, lymphokine-releasing helper-enriched human PBL had no effect on melanoma xenografts, indicating that the tumor inhibition by tumor-cytotoxic allo-activated PBL was not due to recruitment of murine immuno-competent cells by human lymphokines. These results indicate that allo-stimulated, tumor-cytotoxic human PBL given i.v. to nude mice can circulate and inhibit the growth of autologous or allogeneic human melanoma cells implanted s.c.
Animals↗
Phenotypic profile of clones from early cultures of human metastatic melanomas and its modulation by recombinant interferon gamma.
Fifty-six tumor clones isolated by cloning in soft agar from early cultures (before the 10th in vitro passage) of two different human metastatic melanomas (Me9229 and Me28) were characterized by FACS analysis for surface expression of class-I and class-II HLA antigens and of melanoma-associated antigens (MAA) with a panel of 15 monoclonal antibodies (MAbs). A marked phenotypic heterogeneity involving MAA and/or HLA markers was observed among the clones derived from both tumors. The differences among the tumor clones and between them and the uncloned melanoma were qualitative and quantitative for each antigen considered. Clones derived from Me9229 expressed the same HLA profile as the parental culture (class I+, class II-) while strong heterogeneity was observed for MAA expression. Clones from Me28 presented a marked heterogeneity for class-I and class-II HLA antigens but were more homogeneous for MAA. The phenotype of the clones was repeatedly checked over the first month in culture and found to remain generally unchanged and not linked to the cell cycle. However, major changes in antigenic expression of the clones could be observed upon treatment with recombinant interferon-gamma (rIFN-gamma): class-I and -II HLA antigens could be induced or augmented while a moderate inhibition was seen on MAA expression. Furthermore, an apparent hierarchy in expression and/or induction of class-II antigens by rIFN-gamma was observed among the tumor clones. DR antigens were more frequently expressed (Me28 clones) and upon treatment with rIFN-gamma reached higher levels than DP and DQ products. Taken together these results indicate that antigenic heterogeneity for MAA and HLA antigens can be detected in cells isolated from early cultures of human metastatic melanomas and suggest that the original uncloned tumor might be considered as a complex mixed population made up of a number of neoplastic cells each expressing a distinct phenotype which can be modulated by lymphokines such as IFN-gamma.
Antibodies, Monoclonal↗
Growth characteristics of human colorectal and non-small cell lung tumors xenografted into nude mice: possible correlation with prognosis.
Specimens from human colorectal tumors and from non-small-cell lung tumors obtained at surgery were subcutaneously implanted as xenografts in athymic Swiss mice of both sexes to investigate to what extent the properties of the original tumors were maintained. A successful take was obtained in 5 of 9 colorectal tumor and 6 of 11 non-small-cell lung tumor xenografts. Moreover, 44% and 45% of the respective tumors could be established as tumor lines. Neither metastases nor local tumor invasion was observed in tumor-bearing mice. Seven of 9 serially transplantable tumors had a short latency period (14-30.5 days) when first xenografted. No significant changes in tumor histopathology were noted after growth into nude mice. Tumor take was partially related to clinical stage and prognosis of patients. In fact, 8 of 12 specimens from N0 patients failed to grow, whereas 7 of 8 tumors from patients with nodal invasion and/or metastasis grew in nude mice. Moreover, for the group of patients whose tumor was "take - ", the one-year survival was 85%, compared to 40% for the "take + " group (p less than 0.05).
Adult↗
Infusion of autologous alloactivated lymphocytes in melanoma patients: toxicity and immunologic monitoring.
Previous work has shown that infusion of autologous helper-enriched, alloactivated lymphocytes in melanoma patients may induce, in addition to other mild signs of toxicity, a transient but sharp elevation of blood pressure. To avoid such a disturbing symptom, the in vitro protocol of peripheral blood lymphocyte activation has been modified. In the present study we show that such a modification has led to a lower toxicity of autologous lymphocyte infusion in 4 melanoma patients; in particular, hypertension was no longer observed. In addition, an immunologic monitoring was carried out in these patients. In 1 of 4 patients the treatment enhanced the in vitro cytotoxic activity of peripheral blood lymphocytes against autologous tumor cells. Other parameters such as NK activity and T4/T8 ratio did not show significant trends. The possible implications of these findings for clinical trials of adoptive immunotherapy with lymphocytes are discussed.
Adolescent↗
Heterogeneity of clones from a human metastatic melanoma detected by autologous cytotoxic T lymphocyte clones.
The possibility that a single human tumor may be composed of an heterogeneous population of cells with respect to susceptibility to lysis by autologous CTL clones was investigated by testing six cytolytic clones derived by micromanipulation against the autologous metastatic melanoma, Me28, and against 31 clones derived from Me28 by cloning in soft agar. Highly significant differences in the lysis of many tumor clones were observed by three of the CTL effectors in comparison with the cytotoxicity achieved on Me28. These results indicate that cloned cellular reagents can detect heterogeneity among cells isolated from the same melanoma, and suggest that the target determinants recognized on the autologous tumor might be differentially expressed on different neoplastic cells.
Analysis of Variance↗
Analysis of the cellular immune response to and adoptive immunotherapy of a BALB/c lymphoma that cross-reacts with normal DBA/2 cells.
We have previously shown that YC8, a Moloney virus-induced BALB/c lymphoma, is susceptible to lysis by BALB/c anti-DBA/2 effector cells. To further evaluate the relationship between non-H-2 antigens of DBA/2 background and tumor-associated determinants, we investigated the pattern of cytotoxic and proliferative responses induced in BALB/c mice by immunization with YC8 lymphoma. Spleen cells from tumor-immunized animals were restimulated in vitro with YC8 cells and tested for cytotoxicity on target cells of different strains and haplotypes. Cytotoxicity was observed only against YC8, DBA/2 blasts, and P815 (a DBA/2 mastocytoma). BALB/c anti-YC8 effectors were equally blocked by unlabeled YC8 and P815 cells when assayed on YC8 labeled targets. A clonal analysis, however, revealed the existence of at least two types of effectors, one lytic for both P815 and YC8 cells, the other lytic for YC8 cells only. BALB/c anti-YC8 cells proliferate when stimulated both with YC8 and DBA/2 cells in the presence of accessory cells. When tested in an adoptive transfer assay, anti-YC8 cells given i.v. cured 100% of i.v. and 75% of i.p. tumor-injected mice, respectively. When given i.p. anti-YC8 effectors cured 100% of i.p. tumor-injected animals. These results confirm the expression of non-H-2, DBA/2-like antigens on the BALB/c lymphoma YC8 and reveal the presence of additional tumor-associated determinants; both sets of antigens may induce a cellular immune response and elicit immune lymphocytes which can eradicate YC8 cells in an adoptive immunotherapy assay.
Animals↗
Systemic administration of autologous, alloactivated helper-enriched lymphocytes to patients with metastatic melanoma of the lung. A phase I study.
A phase I study was carried out to test the feasibility and toxicity of infusing large numbers of autologous, alloactivated helper lymphocytes into patients with metastatic melanoma. Patient peripheral blood lymphocytes (Pt-PBL) obtained by lymphopheresis and expressing the helper phenotype BT5/9 were separated and stimulated for 48 or 72 h with a pool of PBL from four to six healthy donors. Patients were then infused with such activated lymphocytes over a 2-3 h period. A total of 4 phereses and infusions (2/week for 2 weeks) were carried out for each cycle in each patient. Of the five patients treated, two received a second round of infusions. Infusion of autologous PBL stimulated in vitro for 48 h caused chills, fever, headache, and increased blood pressure. All symptoms disappeared in 2-3 h and were easily controlled by appropriate therapy. When lymphocytes were given after 72 h of allostimulation, no or very mild toxicity was observed. Serum chemistry, coagulation, autoimmunity, and urine analysis showed no gross abnormalities during therapy or follow-up of the patients. Immunological parameters (OKT4/OKT8 ratio, NK activity and cytotoxic T cell activity to autologous melanoma) were evaluated before starting the therapy, during its course and during the 3 to 6 months follow-up. The OKT4/OKT8 ratio increased significantly but transiently soon after the first course of infusions in one of the two patients tested. NK activity increased after 75-100 days in the three patients tested and in one of them it was high even after 180 days. No correlation between NK activity and prognosis was apparent. Cytotoxicity to autologous tumor was assessed in two patients, only of one of whom exhibited an increased activity from 75 to 180 days, which was associated with a prognosis better than that of the negative patient. Five patients were treated: two had progressive disease, two had stable disease for 5 and 6 months, respectively. In the first of these patients, a new cycle of lymphocyte infusions was carried out which caused a measurable reduction of lung tumor nodules whose growth, however, resumed 4 months later. This patient died 14 months after the onset of therapy. The fifth patient had a partial regression of pulmonary and intracranial metastases after therapy, but eventually died 3 months later. These results indicate that infusion of a high numbers of autologous, allostimulated helper PBL is a feasible and safe procedure, which could therefore be used in future studies of adoptive immunotherapy of cancer.
Antibodies, Monoclonal↗
Characterization of a doxorubicin-resistant murine melanoma line: studies on cross-resistance and its circumvention.
A B16 mouse melanoma cell line resistant to doxorubicin was obtained by continuous in vitro exposure to the drug. The ID50 for this line was 200 times higher than that for the parental cell line. The resistant cell line had some biological characteristics similar to those of the sensitive parental cell line, like saturation density and protein content. Differences were found in doubling time which was longer, cloning efficiency which was lower and DNA content which was higher in the resistant as compared to the parental line. Intracellular distribution of doxorubicin was also different having a nuclear-cytoplasmic ratio higher in sensitive than in resistant cells. Melanin content was an unstable feature in the sensitive cell line, whereas melanin was always present in resistant cells. Resistance to doxorubicin was maintained during 50 in vitro passages in the absence of the drug. Cross-resistance was found with vincristine and other anthracyclines, like daunorubicin and 4'-epi-doxorubicin but not with cis-platinum, and a new doxorubicin derivative, 4'-deoxy-4'-iodio-doxorubicin. The B16 line showed a lower resistance index to 4'-deoxy-doxorubicin and 4-demethoxy-daunorubicin (30 and 3 respectively), as compared to doxorubicin. Doxorubicin-resistance was partially circumvented by pretreatment of resistant cells with verapamil, a calcium chelating agent, and by trifluoperazine, a calmodulin-antagonist.
Animals↗
In vivo characterization of a doxorubicin resistant B16 melanoma cell line.
A doxorubicin-resistant line of B16 melanoma (B16VDXR) was obtained in vitro by continuous exposure to increasing concentrations of doxorubicin of an in vitro line (B16V) derived from the in vivo transplanted B16 melanoma. When injected s.c. into mice, B16VDXR exhibited histological features, metastatic behaviour, doubling time and tumourigenic potential similar to those of the parental B16V line. Tumours obtained by implantation of B16VDXR, however, had longer latency and permitted a longer survival time than B16V and had, as in vitro, a higher DNA content. After i.v. inoculation, B16VDXR cells had lower lung colonizing capability compared to B16V. B16V and B16VDXR had significantly lower metastatic potential compared to the B16 melanoma from which they derived. Doxorubicin treatment significantly delayed the growth of B16 and B16V transplanted s.c. and increased the life span of animals bearing B16V. B16VDXR was resistant to doxorubicin treatment when the in vitro resistance index was greater than 100. While the doxorubicin-resistance phenotype was stable in vitro for 50 passages, in vivo the resistance phenotype was lost in 5 passages and tumours grown from s.c. inocula of mixtures of similar percentages of sensitive and resistant cells behaved as sensitive tumours. Cis-diamminedichloroplatinum (II), although marginally active in animals bearing B16V, was highly effective in B16VDXR bearing animals, suggesting a collateral cis-diamminedichloroplatinum (II) sensitivity of the B16VDXR line. After a single i.v. administration, doxorubicin reached initially, in the B16VDXR line, levels similar to those found in the B16 and B16V lines, but its release was faster from the resistant line in comparison with the sensitive ones. Doxorubicin-resistance was not overcome by more frequent treatments with doxorubicin. This doxorubicin-resistant tumour line obtained in vitro and used as a first in vivo transplant, may be a suitable metastaizing model for in vivo study of the mechanisms of resistance and of collateral sensitivity and for screening new drugs.
Animals↗
Classes I and II HLA and melanoma-associated antigen expression and modulation on melanoma cells isolated from primary and metastatic lesions.
Human melanoma cells freshly isolated from 20 patients with primary and 73 patients with metastatic melanomas were analyzed by indirect immunofluorescence staining with monoclonal antibodies (MoAb) to class I (HLA-A, -B, and -C) and class II (HLA-DR and -DQ) antigens and to melanoma associated antigen (MAA). The latter included the GD3-MAA and the high molecular weight MAA. HLA class I antigens were present in 91 and 93% of primary and metastatic tumors, respectively. GD3-MAA was detected in 100% of primary and 80% of metastatic tumors. Whereas the high molecular weight MAA was expressed in 75% of tumors. Sixty % of primary and 50% of metastatic melanomas were stained by anti-HLA-DR MoAb, whereas 38 and 21% of cases, respectively, were stained by anti-HLA-DQ MoAb. Marked phenotypic heterogeneity was evident among primary and metastatic tumors, including different metastases from the same patient. Moreover, in vitro culture of melanoma cells isolated from metastases was associated with an increase from 50 to 75% of tumors stained by anti-HLA-DR MoAb but not of tumors positive for HLA class I antigens and MAA. In vitro incubation with partially purified or recombinant human gamma-interferon enhanced the expression of HLA-DR antigens on all short-term cultured melanoma cells tested but induced and/or augmented the expression of HLA-DQ antigens only in 5 of the 8 cases examined. The average increase in antigenic expression was higher for HLA-DQ than for HLA-DR antigens. Flow cytometric measurement of DNA content of melanoma cells treated with gamma-interferon revealed that the increase of HLA-DR and -DQ expression induced by gamma-interferon was independent from the cell cycle of the tumor cells.
Antibodies, Monoclonal↗
DBA/2-like minor histocompatibility antigens on a BALB/c lymphoma. A BALB/c anti-DBA/2 serum which lyses the tumor and blocks BALB/c anti-tumor and anti-DBA/2 effectors.
We have previously shown that BALB/c anti-DBA/2 T cells can lyse the Moloney virus-induced BALB/c lymphoma YC8. In order to determine whether serologically defined minor histocompatibility antigens (MiHA) cross-reacting with those of DBA/2 tissues are present on YC8, we produced an antiserum directed against non-H-2 antigens by immunizing BALB/c mice with DBA/2 Con A and lipopolysaccharide (LPS)-induced lymphoblasts. In a direct complement-dependent cytotoxicity assay, the antiserum (OR-1) lysed DBA/2 and YC8 but not BALB/c lymphocytes and blasts. No reactions against viral antigens were detected in the antisera as shown by the lack of cytotoxicity on a panel of lymphomas expressing a variety of viral antigens. In addition, OR-1 was able to specifically block a cytotoxic T lymphocyte (CTL), H-2-restricted BALB/c anti-DBA/2 cytotoxic response when bound to DBA/2 or to YC8 target cells. These results indicate that antigens cross-reacting between YC8 lymphoma and DBA/2 tissues are serologically defined MiHA of DBA/2 background and that OR-1 serum can block a CTL reaction by binding to target antigen rather than to major histocompatibility complex products.
Animals↗
Clonal analysis of cytotoxic T-lymphocyte response to autologous human metastatic melanoma.
Peripheral blood lymphocytes (PBL) from a melanoma (Me) patient, previously shown to be unable to react against the autologous tumor (Me 28) after mixed lymphocyte-tumor culture (MLTC), were cultured in vitro with the autologous tumor in MLTC and/or with IL-2-containing supernatants. T-cell clones were then obtained by limiting dilution and by micromanipulation. Eleven clones, selected for autologous tumor (Auto-Tu) cytotoxicity, were tested for specificity on a panel of 17 cell cultures of normal and neoplastic origin, revealing a complex spectrum of lytic activities. Three groups of clones could be identified depending on the patterns of cytotoxicity. One clone (B11.12) lysed Me28 and expressed a borderline reactivity against one allogeneic Me. A second group of clones (A4, A4.18, H10, E12, C9) lysed the Auto-Tu and allogeneic Me. The last group of clones (A4.2, A4.3, A4.4, A7, B7) expressed a broader pattern of reactivity with significant cytotoxicity against targets of different histologic origin. Furthermore, the second and third groups of clones lysed K562 while B11.12 did not. The Auto-Tu-restricted reactivity of clone B11.12, confirmed by a further test on 13 allogeneic Me and on autologous IL-2 cultured lymphocytes, suggests the recognition of antigenic structures preferentially expressed on Me28. Blocking studies, performed with monoclonal antibodies (MAb), revealed that an anti-HLA class I MAb (w6/32), but not two anti-DR MAbs (L243, DI.12), could inhibit the cytotoxic activity of clones B11.12 on Me28. A significant blocking effect by w6/32 on Me28 was achieved also with clones A4.4 and H10 but not with clones A4.2, A4.3 and A7. The phenotype of all clones was T3+, T4-, T8+, HNK-I-, suggesting that the anti-tumor effectors were of the T-cell lineage. Taken together, these data indicate that it is possible to isolate anti-tumor CTL-clones after MLTC from a PBL population of a metastatic melanoma patient. Furthermore, we present evidence suggesting a role of class-I antigens in the interaction of some cloned effectors with the autologous tumor target.
Antibodies, Monoclonal↗
Genetic unresponsiveness to a murine fibrosarcoma determined by the host genetic environment but not by lymphocyte precursor genotype.
(BALB/c X C3Hf) (H-2d X H-2k)F1 hybrid mice but not parental BALB/c or other BALB/c X H-2k F1 hybrids, were unresponsive in transplantation and in neutralization (Winn) assay against a 3-methylcholanthrene-induced BALB/c fibrosarcoma. In BALB/c mice the antitumor activity revealed by Winn assay with antitumor immune lymphoid cells was shown to be tumor specific and mediated by Thy 1+ cells. Mouse chimeras were constructed by injecting fetal liver cells into irradiated recipients. BALB/c----(BALB/c X C3Hf)F1 and control (BALB/c X C3Hf)F1----(BALB/c X C3Hf)F1 chimeras were unable to develop a transplantation immunity against the immunizing tumor, whereas (BALB/c X C3Hf)F1----BALB/c chimeras were able to respond to the immunizing tumor. Thus, unresponsiveness was shown to be due to a defect in the maturation of precursor stem cells both of parental and F1 hybrid origin in the body of the (BALB/c X C3Hf)F1 animals.
Animals↗
Disulfide-linked surface molecules of monoclonal antigen-specific suppressor T cells: evidence for T cell receptor structures.
By two-dimensional polyacrylamide gel electrophoresis analysis under nonreducing/reducing conditions, five proteins with interchain disulfide bridges are revealed on the surface of the suppressor T cell lymphoma line LH8-105 obtained by radiation leukemia virus-induced transformation of hen egg-white lysozyme-specific suppressor T lymphocytes. Two disulfide-linked surface proteins expressed by LH8-105 cells have been positively identified by immunoprecipitation with specific antisera. The major labeled membrane protein of LH8-105 cells is the murine leukemia virus env glycoprotein gp70. The second disulfide-linked molecule identified on LH8-105 cells has a molecular mass of 84 kDa under nonreducing conditions and 42 kDa after reduction, and is immunoprecipitated by an antiserum which recognizes the T cell receptor for antigen. A disulfide-linked molecule of a similar molecular mass is also immunoprecipitated from surface-labeled LH8-105 cells by a rabbit antiserum directed against a synthetic peptide predicted from the nucleotide sequence of a cDNA clone encoding the beta chain constant region of a helper T cell hybridoma. Therefore, a dimeric structure comparable to the T cell receptor expressed by cytotoxic and helper T cells is present on the cell surface of these monoclonal antigen-specific suppressor T cells.
Animals↗
Autologous cellular immune response to primary and metastatic human melanomas and its regulation by DR antigens expressed on tumor cells.
Evidence for heterogeneity of several biological features of human malignant melanoma (Me) like morphology, cytogenetics, oncogenes activation, antigenic expression, metastatizing capacity and procoagulant activity are briefly reviewed in an attempt to distinguish findings related to primary vs. metastatic lesions. In our own studies monoclonal antibodies were used to study expression of MHC class I, class II products and of Me-associated antigens (MAA) on primary and metastatic Me cells. High expression of class I antigens was found in a high percentage of both primary and metastatic tumors, whereas DR and MAA showed a significant variation (from 3 to 90% of cells) in expression both in primary and in metastatic Me. When autologous cell-mediated immune responses were evaluated, it was found that Me cells from primary tumors but not those from lymph node metastases were able to stimulate autologous lymphocytes to proliferate and become cytotoxic for autologous Me. Clonal analysis of cytotoxic lymphocytes was then carried out in order to see whether the lack of lymphocytes reactivity to metastatic cells was due to the absence or to a low frequency of cytotoxic cells in the unstimulated PBL. CTL clones cytotoxic for autologous Me (Auto-Me) cells were indeed isolated. Three classes of CTL clones were identified: 1) one which is cytotoxic for Auto-Me; 2) a second one which lyse Auto-Me and allogeneic Me; and 3) a third one which is cytotoxic for Auto-Me and allogeneic normal and neoplastic cells. Metastatic Me cells, however, had the ability to suppress the stimulation of autologous PBL by alloantigens or IL-2. This effect was dose-dependent and was not due to absorption of IL-2 by Me cells. Since it has been reported that Me cells express class II MHC antigens, we investigated whether there was any correlation between autologous immune responses and DR expression on Me cells. Autologous lymphocytes stimulation was found to occur only with DR+ Me cells from primary lesions, whereas metastatic cells, either DR+ or DR-, did not stimulate autologous PBL. Moreover, the suppressive effect of metastatic Me cells was associated with their expression of DR antigens. The modulation of DR antigens on Me cells by Interferon-gamma correlated positively with their suppressive capacity. Thus, it appears that primary Me can behave differently from the metastatic one in their interactions with the immune system of autologous host. These findings suggest that DR antigens on Me cells may have an important role in the regulation of autologous immune responses.
Antigens, Neoplasm↗
Adoptive immunotherapy of a BALB/c lymphoma by syngeneic anti-DBA/2 immune lymphoid cells: characterization of the effector population and evidence for the role of the host's non-T cells.
It has been previously shown that the BALB/c lymphoma YC8 is susceptible to lysis by syngeneic anti-DBA/2 lymphocytes and that YC8-bearing BALB/c mice can be cured by adoptive transfer of such immune effectors. In this study in vivo and in vitro functions of the curative immune lymphocytes have been evaluated together with the role of the host immune system in the mechanism of tumor eradication. It was found that the curative anti-DBA/2 lymphocytes were not directly cytotoxic to YC8 cells although they developed into YC8-lytic cells after in vitro restimulation with YC8. In vivo, the immune lymphocytes were able to mediate a tumor-specific delayed type hypersensitivity reaction against YC8 but had a low tumor-neutralizing activity in the Winn assay. Proliferation of infused BALB/c anti-DBA/2 lymphocytes was necessary for the in vivo therapeutic effect, since irradiation of effector cells or treatment of the donor immune lymphocytes with vinblastine abolished their curative capacity. Immunodepression of the T cell compartment of the prospective tumor-bearing animals by thymectomy plus irradiation or its abrogation in B mice (thymectomized, lethally irradiated, and reconstituted with fetal liver cells) did not interfere with the therapeutic effect of the transferred anti-DBA/2 lymphocytes. Blocking the macrophage functions of the host by carrageenan, however, abolished the therapeutic effect of immune lymphocytes. These data indicate that a radiation-resistant, non-T cell is involved in the tumor eradication induced by anti-DBA/2 lymphocytes. It was also shown that cured mice, tested 90 days after therapy, become resistant to 5 X 10(3) LD80 YC8 cells and that this resistance was due to the presence of memory cells derived from the transferred and not from the host lymphocyte population.
Animals↗
Allostimulation of patients' lymphocytes generates both T and NK-like cells cytotoxic for autologous melanoma.
Killing of autologous melanoma (auto-Me) was obtained with pooled allostimulated peripheral blood lymphocytes (PBL) in 34/42 cases and found not to be due to a cross-reactivity between melanoma and allogeneic normal antigens. To see whether generation of tumour cytotoxic PBL by allostimulation was due to release of IL-2, PBL from 34 patients were divided into two aliquots and stimulated either by alloantigens or IL-2. Allostimulated PBL were cytotoxic for auto-Me in 30/34 cases (85%) whereas IL-2 generated tumour cytotoxic cells in 22/34 cases (64%). Lysis of K562, a target for monitoring NK-like activity, was obtained in 95-100% of cases with both stimuli. A similar frequency of OKT3+, OKT4+, OKT8+ and HNK1+ cells was found in PBL activated by allostimulation and IL-2, whereas a higher frequency of OKM1+ cells was evident in IL-2-stimulated PBL. Cold-target competition studies indicated that allostimulation generated at least two different types of effectors, one lytic to auto-Me but not to K562, and the other which lysed both targets. Allostimulated, FACS-separated T3- cells killed both auto-Me and K562 cells whereas T3+ cells lysed only auto-Me. It is concluded that allostimulation generated two subpopulations of auto-Me killer cells, one of the T lineage and the other NK-like, which both can destroy auto-Me targets.
Antibodies, Monoclonal↗