Effective adoptive immunotherapy by T-LAK cells retargeted with bacterial superantigen-conjugated antibody to MUC1 in xenografted severe combined immunodeficient mice

To reinforce cytotoxic activity and the targeting ability of lymphokine-activated killer cells with a T-cell phenotype (T-LAK) for adoptive immunotherapy against human bile duct carcinoma (BDC), staphylococcal enterotoxin A (SEA) was conjugated chemically with MUSE11 monoclonal antibody (MUSE11 mAb), directed to the MUC1 antigen, using N-succinimidyl 3-(2-pyridyldithio) propionate and 2-iminothiolane HCl. Both SEA-conjugated MUSE11 mAb (SEA-MUSE11) and the F(ab')2 of MUSE11 mAb (SEA-F(ab')2) showed significant enhancement of T-LAK cell tumor neutralization for MUC1 positive-target tumor cells, even with a concentration of 0.01 microg/ml at an E:T ratio of 5:1 in vitro. In this in vitro test, MUC1-positive BDC cells were observed to attach to surrounding T-LAK cells in the presence of SEA-MUSE11 or SEA-F(ab')2. Remarkable tumor growth inhibition was observed in BDC-grafted severe combined immunodeficient mice to which 2 x 10(7) T-LAK cells preincubated with 2 microg of SEA-MUSE11 or SEA-F(ab')2, together with recombinant interleukin 2 (500 IU), were administered i.v. for 4 consecutive days, when tumor size was 5 mm in diameter. These results point to a promising adoptive immunotherapy for patients with BDC.     

Biodistribution of charged F(ab')2 photoimmunoconjugates in a xenograft model of ovarian cancer

The effect of charge modification of photoimmunoconjugates (PICs) on their biodistribution in a xenograft model of ovarian cancer was investigated. Chlorin(e6)c(e6) was attached site specifically to the F(ab')2 fragment of the murine monoclonal antibody OC125, directed against human ovarian cancer cells, via poly-1-lysine linkers carrying cationic or anionic charges. Preservation of immunoreactivity was checked by enzyme-linked immunosorbent assay (ELISA). PICs were radiolabelled with 125I and compared with non-specific rabbit IgG PICs after intraperitoneal (i.p.) injection into nude mice. Samples were taken from normal organs and tumour at 3 h and 24 h. Tumour to normal 125I ratios showed that the cationic OC125F(ab')2 PIC had the highest tumour selectivity. Ratios for c(e6) were uniformly higher than for 125I, indicating that c(e6) became separated from 125I. OC125F(ab')2 gave highest tissue values of 125I, followed by cationic OC125F(ab')2 PIC; other species were much lower. The amounts of c(e6) delivered per gram of tumour were much higher for cationic OC125F(ab')2 PIC than for other species. The results indicate that cationic charge stimulates the endocytosis and lysosomal degradation of the OC125F(ab')2-pl-c(e6) that has bound to the i.p. tumour. Positively charged PICs may have applications in the i.p. photoimmunotherapy of minimal residual ovarian cancer.     

Sequential treatment with vindesine-ifosfamide-platinum (VIP) chemotherapy followed by platinum sensitized radiotherapy in stage IIIB non-small cell lung cancer: a phase II trial

Monoclonal antibody (mAb) A33 detects a glycoprotein homogeneously expressed by > 95% of human colon cancers and by normal colon cells. The A33 antigen is not secreted or shed and after mAb A33 binds to antigen on the cell membrane, a fraction of membrane-bound mAb A33 is internalized into endosomes. Phase I 131I-mAb A33 biodistribution studies have shown consistent, specific tumor-targeting, and phase I radioimmunotherapy trials with 131I- or 125I-mAb A33 have demonstrated antitumor effects. Here we describe a nude mouse model that was established using a human colon cancer cell line, SW1222, which grows as a relatively hypovascular, invasive heterotransplant when injected i.m. Peak uptake of 131I-labeled or 111In-chelated mAb A33 was observed at 48-96 h, with a mean of 34% (SE +/- 5.0) and 46.7% (SE +/- 1.7) injected dose per gram of tumor tissue, respectively. 111In-mAb A33 was retained in tumor tissue longer than halide radioimmunoconjugates. The specificity of antibody localization was assessed using a control antibody (tumor uptake and pharmacokinetics), a control tumor, corrections for vascular antibody blood-pooling in tumor tissue, and blocking of radiolabeled mAb A33 localization by pretreating mice with excess unlabeled mAb A33. These experiments demonstrate that mAb A33 localization in tumor was specific, and they emphasize the unexpected rapidity with which the antibody localizes. Our conclusions were confirmed by immunohistochemical techniques which allowed direct visualization of localization and distribution of the humanized version of mAb A33 in tumor tissue. Furthermore, antibody doses approximating tumor-saturating doses demonstrated that a homogeneous distribution of antibody in tumor is possible. This model will be valuable for studies focusing on general physiologic aspects of antibody-to-tumor cell localization and critical as a guide to the evaluation of various A33 antibody constructs and combinations with other therapies for the treatment of colon cancer.     

Increased tumor localization by monoclonal antibody A7 after F(ab')2 fragmentation in athymic nude mice bearing human pancreatic carcinomas

Much recent research has been directed toward the use of monoclonal antibodies (MoAbs) for the immunodetection of solid tumors. In pancreatic cancer, conventional immunoscintigraphy using intact MoAbs remains disappointing. In this study, 125I-labeled F(ab')2 fragments produced by pepsin digestion of MoAb A7 were injected intravenously into nude mice bearing human pancreatic cancer, HPC-YS, xenografts that have previously been shown to react specifically with MoAb A7. The tumor tissue/blood ratio of 125I-labeled F(ab')2 fragments of MoAb A7 increased with time and was much higher than those for normal tissues. Moreover, the tumor tissue/blood ratio of 125I-labeled F(ab')2 fragments was greater than that of intact MoAb A7, although the F(ab')2 accumulation was less than that of intact MoAb A7 in the tumor. These results suggest that F(ab')2 fragments of MoAb A7 may be suitable carriers of radionuclides for immunodetection of human pancreatic cancer.     

Maternal transmission of human immunodeficiency virus-1

We have analysed the binding of variable domain-identical mouse monoclonal antibodies (mAb) of the IgG3, IgG1 and IgG2b subclasses, as well as F(ab')2 fragments derived from the IgG3 and IgG1 mAb, to a multivalent glycoprotein target. Using a biosensor device (BIAcore, Pharmacia Biosensor) that measures the mass of the antibody (or other receptor molecule) deposited on a sensor chip displaying the relevant epitopes, we found that the IgG3 mAb binds more effectively than the other antibody species at a high but not a low epitope density. The greater functional affinity associated with the IgG3 mAb, at high epitope density, was correlated with both slower dissociation rate constants and faster association rate constants in comparison with the IgG1 and IgG2b mAb and the F(ab')2 fragments derived from the IgG3 and IgG1 mAb. Evidence for slower dissociation kinetics for the IgG3 mAb versus the IgG1 and IgG2b mAb was also obtained by ELISA and flow cytometry. These results demonstrate that: (1) differences in heavy chain constant (CH) domains can significantly influence apparent functional affinity for multivalent antigen, as determined without the use of covalently modified primary or secondary antibodies; (2) differences in CH domains can alter both association and dissociation rate constants for interactions between IgG antibodies and multivalent antigen; and (3) these effects of CH domains depend on epitope density. The effect of constant region differences on the apparent association rate constants suggests new approaches for achieving better binding or functional effectiveness through antibody engineering.     

The assessment of the nutritional status of patients in the terminal stage of liver disease who are candidates for orthotopic liver transplantation

We evaluated the intravenous infusion of a cocktail of I-131 anti-CEA and anti-CA19-9 monoclonal antibody F(ab')2 (IMACIS-1) in patients with gastrointestinal neoplasm and liver metastases in order to assess its efficacy in detecting the presence of cancer. Seven patients with primary or recurrent gastrointestinal cancer in whom liver metastases were also detected were studied. Accumulation of radioactivity in the primary tumor was seen in only one patient. Visualization of the liver metastases was achieved in all patients. Thus detection of liver metastasis was better than in primary or recurrent tumors. While tumor visualization was most often seen in the 3 day image, optimal visualization of the tumor was seen at 5-7 days. There was no correlation between the serum concentration of CEA or CA19-9 and the visualization of tumors. Serum kinetics of I-131 IMACIS-1 showed biexponential components with a 1st phase T1/2 of 5.0 hours and 2nd phase T1/2 of 34.7 hours. The mean whole body (I-131) half-life determined from the whole-body scans was 1.95 days. The mean urinary excretion of I-131 in 7 days was 85%. This value agreed closely with total radioactivity retention detected by scanning. This series of studies demonstrated the potential utility of a cocktail of antibodies consisting of an anti-CEA and an anti-CA19-9 monoclonal F(ab')2.     

Immunohistochemical metallothionein expression in thymoma: correlation with histological types and cellular origin

In radioimmunotherapy, the long circulation times of antibody radioconjugates correlate with high relative radiation doses to nontumor tissues. Tumor/normal tissue ratios can be significantly improved by using targeting molecules with shorter circulation times. IFabs are multimers of VH-CH1-linker-VK-CK monomers. The lack of the Fc region in IFabs should lead to circulation times that are shorter than those of IgG molecules. The monomers assemble into disulfide-bond-stabilized multimers, 90% of which are 100 kDa dimers (IFab2). IFab2s should not be rapidly eliminated through kidney filtration because their molecular weight is above the threshold for renal passage. We report the first experimental in vivo tests for 125I-IFab radioconjugates derived from a humanized version of the anti-breast mucin monoclonal antibody BrE-3. Biodistributions are reported for athymic nude mice carrying human mammary tumor MX-1 xenografts. The T1/2 beta's for the different tissues ranged from 13.3 h for blood to 19.9 h for tumor. Therefore, IFab radioconjugates cleared the body with a rate comparable to that of F(ab')2 fragments. Except for stomach, tumor/nontumor dose ratios were significantly better for IFabs than for the parent antibody (BrE-3)4 days after injection.     

Accurate measurement of intrinsic positive end-expiratory pressure: how to detect and correct for expiratory muscle activity

The basic amino acid L-lysine was administered to mice in an attempt to circumvent unwanted renal accumulation of 67Cu-labelled F(ab')2 fragments derived from the anti-NCAM IgG1, SEN7 and anti-CEA IgG1 monoclonal antibody (MAb)35. In control experiments, significant renal uptake of both 67Cu-labelled F(ab')2 fragments was observed, radiolabel being primarily localised to proximal tubules in the renal cortex. Following optimised L-lysine dosing protocols, renal uptake of 67Cu-MAb35 F(ab')2 was inhibited by up to 42%. Surprisingly, little inhibition (< 10%) of 67Cu-SEN7 F(ab')2 uptake was observed. Experiments to investigate this differential inhibition indicated that inhibition of MAb35 F(ab')2 uptake was relatively short-lived (approx. 6 hr), whilst no apparent differences were found in blood clearance rates between either 67Cu-F(ab')2 fragment. L-lysine administration caused a significant diuresis with high levels of intact 67Cu-labelled SEN7 and MAb35 F(ab')2 appearing in the urine, possibly due to blockade of renal uptake and lysine-induced increases in glomerular membrane permeability. Iso-electric focusing studies failed to identify any charge differences between the 67Cu-labelled F(ab')2 fragments, although a cathodal migration of all 67Cu-labelled samples, presumably due to the net positive charge conferred by addition of 67Cu2+ ions, was observed. Our results demonstrate that in addition to net charge, other unidentified characteristics may influence renal accumulation of radiometal-labelled F(ab')2 fragments and their inhibition by L-lysine.     

Chimeric anti-angiogenin antibody cAb 26-2F inhibits the formation of human breast cancer xenografts in athymic mice

Angiogenin (Ang), an inducer of neovascularization, is secreted by several types of human tumor cells and appears critical for their growth. The murine anti-Ang monoclonal antibody (mAb) 26-2F neutralizes the activities of Ang and dramatically prevents the establishment and metastatic dissemination of human tumor cell xenografts in athymic mice. However, for use clinically, the well-documented problem of the human anti-globulin antibody response known to occur with murine antibodies requires resolution. As a result, chimeric as well as totally humanized antibodies are currently being evaluated as therapeutic agents for the treatment of several pathological conditions, including malignancy. Therefore, we have constructed a chimeric mouse/human antibody based on the structure of mAb 26-2F. Complementary DNAs from the light and heavy chain variable regions of mAb 26-2F were cloned, sequenced, and genetically engineered by PCR for subcloning into expression vectors that contain human constant region sequences. Transfection of these vectors into nonproducing mouse myeloma cells resulted in the secretion of fully assembled tetrameric molecules. The chimeric antibody (cAb 26-2F) binds to Ang and inhibits its ribonucleolytic and angiogenic activities as potently as mAb 26-2F. Furthermore, the capacities of cAb 26-2F and its murine counterpart to suppress the formation of human breast cancer tumors in athymic mice are indistinguishable. Thus cAb 26-2F, with its retained neutralization capability and likely decreased immunogenicity, may be of use clinically for the treatment of human cancer and related disorders where pathological angiogenesis is a component.     

Thrombolytic therapy in Missouri hospital emergency departments: compliance with the National Heart Attack Alert Program guidelines

Adhesive interactions between leukocytes and endothelium are required for subsequent leukocyte extravasation toward inflammatory sites. Understanding the possible kinetic expression of vascular cell adhesion molecule-1 (VCAM-1) in the middle ear cavity during an inflammatory cascade in vivo may be important for clarifying local immunological responses in otitis media. Two inflammatory models were produced in the rat and involved acute middle ear mucosal and cutaneous inflammation induced after inoculation or intradermal injection of lipopolysaccharide (LPS). After intravenous injection of both 125I-labeled anti-VCAM-1 and 131I-labeled control monoclonal antibody (mAb), the kinetic expression of VCAM-1 in the middle ear and skin was assessed by local radionuclide uptake. The biodistribution of an 125I-labeled anti-VCAM-1 mAb as a potential detector of focal inflammation was examined in normal rats. Both inflammatory lesions were characterized by early and sustained (up to 24 h) expression of VCAM-1, with maximal expression at 4 h after LPS stimulation. The kinetics of VCAM-1 expression was similar among the middle ear mucosa or skin specimens studied and different stimulation methods. A similar biodistribution and clearance of radioactivity between 125I-labeled anti-VCAM-1 mAb and 131I- or 99mTc-labeled control mAb were observed. The present result suggest that functional VCAM-1 induced by LPS is expressed in both middle ear tissue and skin lesions and may play a role in the initial stage of inflammatory response produced. Although VCAM-1 upregulation is a very early event in the inflammatory cascade, 125I-labeled anti-VCAM-1 mAb may be useful for the early detection of focal inflammation in the middle ear.     

Clinical comparison of radiolocalization of two monoclonal antibodies (mAbs) against the TAG-72 antigen

Ten patients with colorectal cancer metastases received 125I-B72.3 and 131I-CC49 prior to laparotomy (five patients received 1 mg, and five 20 mg of each mAb). Tumor:serum ratios of 131I-CC49 were better than those of 125I-B72.3 (P < 0.01 at 1 mg; P = 0.05 at 20 mg; P < 0.01 at both doses). All known lesions > or = 1 cm in diameter were visualized at the 20 mg dose. There was no difference in absolute tumor uptake of 125I-B72.3 or 131I-CC49. We conclude that mAb CC49 has better relative uptake in colorectal cancers than mAb B72.3.     

Osmolar gap with minimal acidosis in combined methanol and methyl ethyl ketone ingestion

Induction of an experimental disease resembling murine systemic lupus erythematosus (SLE), has been achieved in mice by immunization with a human monoclonal anti-DNA antibody, bearing a common idiotype, designated 16/6 Id. In the present study we report the preparation of F(ab')2 proteolytic fragments of the human 16/6 Id mAb and the ability of the latter to induce experimental-SLE in mice. Following immunization with the F(ab')2 fragment, mice developed antibodies bearing the 16/6 Id, anti-16/6 Id and a variety of autoantibodies, similar to mice immunized with the whole 16/6 Id molecule. Serological manifestations of the disease such as leukopenia, proteinuria and renal damage, were developed following the immunization with the 16/6 Id F(ab')2 proteolytic fragments. These results demonstrate the pathogenic role of the F(ab')2 fragment that bears the 16/6 Id.     

Immunoscintigraphy of bone sarcomas--results in 5 patients

The feasibility of using the murine monoclonal antibody, TP-1, for clinical immunoscintigraphy was examined in a pilot study involving 5 patients with bone sarcomas. 131I-labelled F(ab')2 antibody fragments were injected in doses of 0.8-1.0 mg (90-130 MBq), and the accumulation of radioactivity was examined by scintigraphy, and assessed by direct measurements on biopsied tumour and normal tissue. One osteosarcoma patient had a primary tumour in the femur, whereas the other 4 had single lung metastases detected by other diagnostic methods. Immunoscintigraphy of the femoral primary was optimally visualised after 22 h. In 2 patients, the method failed to detect lung metastasis, in 1 of the cases possibly related to less than optimal methodological conditions. In 2 other patients, increased accumulation of radioactivity indicated one and three lung tumours, in addition to the single metastasis observed by X-ray and CT scanning, tumours that were later confirmed and removed surgically. The concentration of radioactivity in tumour and normal tissues 44-72 h after antibody injection could be measured in 4 patients. The tumour to blood ratios were in the range of 1.2-4.2, compared to 0.1-0.8 for various normal tissues. The results indicate that immunoscintigraphy with TP-1 antibody fragments have a potential for early detection of lung metastases in patients with bone sarcoma.     

Iodine-131-labeled antitenascin monoclonal antibody 81C6 treatment of patients with recurrent malignant gliomas: phase I trial results

PURPOSE: To determine the maximum-tolerated dose (MTD) of iodine 131 (131I)-labeled 81C6 monoclonal antibody (mAb) in brain tumor patients with surgically created resection cavities (SCRCs) and to identify any objective responses to this treatment. METHODS: In this phase I trial, eligible patients were treated with a single injection of 131I-labeled 81C6. Cohorts of three to six patients were treated with escalating dosages of 131I (starting dose of 20 mCi with a 20-mCi escalation in subsequent cohorts) administered through an Ommaya reservoir in the SCRC. Patients were followed up for toxicity and response until death or for a minimum of 1 year after treatment. The SCRC patients, who were previously irradiated, were followed up without additional treatment unless progressive disease was identified. RESULTS: We administered 36 treatments of 131I doses up to 120 mCi to 34 previously irradiated patients with recurrent or metastatic brain tumors. Dose-limiting toxicity was reached at 120 mCi and was limited to neurologic or hematologic toxicity. None of the patients treated with less than 120 mCi developed significant neurologic toxicity; one patient developed major hematologic toxicity (MHT). The estimated median survival for patients with glioblastoma multiforme (GBM) and for all patients was 56 and 60 weeks, respectively. CONCLUSION: The MTD for administration of 131I-labeled 81C6 into the SCRCs of previously irradiated patients with recurrent primary or metastatic brain tumors was 100 mCi. The dose-limiting toxicity was neurologic toxicity. We are encouraged by the minimal toxicity and survival in this phase I trial. Radiolabeled mAbs may improve the current therapy for brain tumor patients.     

Interferon-gamma and monoclonal antibody 131I-labeled CC49: outcomes in patients with androgen-independent prostate cancer

To assess the tumor targeting, safety, and efficacy of monoclonal antibody 131I-labeled CC49 in patients with androgen-independent prostate cancer, 16 patients received 75 mCi/m2 of the radiolabeled antibody after 7 days of IFN-gamma pretreatment. Sequential tumor biopsies in three patients showed a median 5-fold (range, 2-6-fold) increase in the proportion of cells staining positively for the TAG-72 antigen, whereas one showed a decrease in staining. Fourteen patients received 131I-labeled CC49, whereas 2 showed a disease-related decrease in performance status, precluding antibody treatment. The antibody localized to sites of metastatic androgen-independent prostate cancer in 86% (12 of 14; 95% confidence interval, 57-95%) of cases. Both osseous and extraosseous sites were visualized, and in six (42%) patients, more areas were visible when the radioimmunoconjugate was used than were apparent when conventional scanning techniques were used. The localization of the conjugate in the marrow cavity was usually a site not visualized by the radionuclide bone scan, in which the isotope localizes primarily to the tumor-bone interface. The dose-limiting toxicity was thrombocytopenia because five (36%) patients showed grade IV and seven (50%) showed grade III effects. In addition, six (42%) patients, four of whom were hospitalized, showed a flare in baseline pain, and four showed a decrease in pain. No patient showed a >50% decline in prostate-specific antigen, although radionuclide bone scans remained stable in four cases for a median of 4 months. The results are consistent with dosimetry estimates showing that the delivered dose to tumor was subtherapeutic and suggest that approaches that exclusively target the bone tumor interface or the marrow stroma may be unable to completely eradicate disease in the marrow cavity. For CC49, improving outcomes would require repetitive dosing, which was precluded by the rapid development of a human antimouse antibody response.     

My association with Ludwik Hirszfeld, Wroc?aw 1945-1954

Intravenous injection of the murine monoclonal anti-CA125 antibody B43.13 (Ovarex: Ab1) into ovarian cancer patients led to the induction of an idiotypic network. Of the 75 patients who received one to ten injections of a 2-mg dose of the antibody, 48 developed anti-(mAb B43.13) antibodies (Ab2); 18 of these patients also had elevated levels of anti-[anti-(mAb B43.13)] antibodies (Ab3; = anti-CA125 antibodies) compared to pre-injection values. Characterization of these antibodies revealed that the binding to CA125 could be inhibited by mAb B43.13 in most samples. Human anti-CA125 antibodies or Ab3 purified from patient serum samples specifically recognized human ovarian tumor cells and tissues expressing CA125. In addition, these anti-CA125 antibodies were able to conduct Fc-mediated tumor cell killing (antibody-dependent cell-mediated cytotoxicity). This raises the possibility of using an Ab1 for anti-idiotype induction immunotherapy of cancer.     

Anti-ICAM-1 monoclonal antibody R6.5 (Enlimomab) promotes activation of neutrophils in whole blood

R6.5 (BIRR-1, Enlimomab), a murine IgG2a mAb to the human ICAM-1, inhibits leukocyte adhesion to the vascular endothelium, thereby decreasing leukocyte extravasation and inflammatory tissue injury. In initial clinical trials, R6.5 proved to be beneficial in reducing both disease activity in refractory rheumatoid arthritis and the incidence of acute rejection after kidney and liver allograft transplantations. However, adverse effects such as fever, leukopenia, or cutaneous reactions were not infrequent. We studied the effects of R6.5 on neutrophil function in whole blood samples ex vivo. Surprisingly, at the concentrations achieved in clinical trials, R6. 5 activated neutrophilic granulocytes, as indicated by a significant increase in expression of the adhesion molecule beta2-integrin CD11b, a concurrent decrease in L-selectin expression, and an enhancement of the oxidative burst activity. Neutrophil activation was not exerted by an anti-ICAM-1 mAb of the IgG1 isotype, by isotype-matched, irrelevant anti-2-phenyloxazolone mAb, or by F(ab')2 fragments of R6.5. Neutrophil activation was completely inhibited by soluble complement receptor type 1. We conclude that in whole blood, R6.5 activates resting neutrophils in a complement-dependent manner. This finding can explain, at least in part, the side effects associated with R6.5 therapy.     

SLS-irritated human skin shows no correlation between degree of proliferation and TEWL increase

Vascular endothelial growth factor (VEGF), a very important in the process of tumor angiogenesis, was chosen as a target in a study to determine whether manipulation of angiogenesis with antibody against VEGF may interrupt tumor growth and metastasis. Anti-VEGF antibody was obtained from immunized rabbits, purified on an affinity column, and identified as neutralized antibody by Mile's assay. IVTA2MA891, a murine spontaneous breast cancer with a high rate of metastasis in lung in TA2 x 615 F1 mice, was chosen as an animal model in this study, because of the high expression of VEGF in the primary tumor as well as in the lung metastatic tumor. The anti-VEGF antibody could inhibit growth of S180 sarcoma in a dose-dependent manner, and the inhibition rate could reach 41.0% with a dose of 200 microg mouse(-1) day(-1). Anti-VEGF antibody could inhibit tumor growth by 76.2% in nude mice bearing human gastric cancer (MGC 803). When anti-VEGF antibody was combined with 131I-3H11, a murine monoclonal antibody conjugated with 131I, only one of five nude mice developed tumor and 84.0% more inhibition of tumor growth was obtained in comparison with treatment by 131I-3H11 alone. The growth of the primary tumor was inhibited by 44.0% and the number and size of the metastatic foci in the lungs were reduced by 73.0% and 83.7% respectively in the animal model, with a high rate of metastasis in lung. The anti-VEGF antibody may be potentially useful for clinical treatment of cancer and metastasis.     

Inhibition of bispecific monoclonal antibody (bsAb)-targeted cytolysis by human anti-mouse antibodies in ovarian carcinoma patients treated with bsAb-targeted activated T-lymphocytes

T lymphocytes of 8 patients with ovarian cancer were targeted to the tumor cells using F(ab')2 fragments of a bispecific monoclonal antibody (bsAb), specific for CD3 (a component of the T lymphocyte receptor for antigen) and for the folate receptor MOv18 (overexpressed by ovarian carcinoma cells) as part of a phase I/II study. Phase I (days 0 to 3) consisted of increasing intraperitoneal (i.p.) numbers (10(6)-10(9)) of bsAb-targeted T lymphocytes plus low-dose interleukin-2 (IL-2). Phase II (days 6 to 13, and 27 to 33) consisted of daily i.p. infusions of 10(9) targeted T lymphocytes, 2 mg soluble bsAb, and low-dose IL-2. Using enzyme-linked immunosorbent assays (ELISA), human anti-mouse antibodies (HAMA) were detected in all patients: in the serum from day 13 onwards and in the peritoneal fluid from day 20 onwards. A significant proportion of the HAMA appeared to be directed against the idiotypes of the bsAb specific for CD3 and MOv18, as suggested by (1) the clearly higher ELISA titers against OC/TR bsAb as compared to those against a monoclonal antibody (MAb) with unrelated specificity, and (2) failure to abrogate the capacity of peritoneal fluid containing HAMA to block the binding of OC/TR bsAb to MOv18+ or CD3+ cells by absorption of human anti-mouse IgG-framework antibodies in peritoneal fluid to immobilized mouse IgG. The OC/TR-targeted cytolysis of the MOv18+ ovarian carcinoma cell line Igrov-I by autologous T lymphocytes was inhibited by peritoneal fluid samples containing relatively high HAMA titers. Such inhibitory activity was never detected at the start of phase II, but coincided with the last series of i.p. infusions of targeted T lymphocytes in 2 patients.     

Clinical pharmacology and tissue disposition studies of 131I-labeled anticolorectal carcinoma human monoclonal antibody LiCO 16.88

Antibody LiCO 16.88 is a human IgM recognizing a 30- to 45-kDa intracytoplasmic antigen present in human adenocarcinoma cells. An 8-mg sample of antibody labeled with 5 mCi 131I was co-administered i.v. with 120 mg (three patients), 240 mg (three patients) or 480 mg (four patients) unlabeled antibody as a 4-h infusion. The plasma half-life was 24 +/- 1.2 h and the immediate apparent volume of distribution was 5.2 +/- 0.2 l at the 28-mg dose level. The plasma half-lives and the cumulative urinary excretion of radiolabel did not seem to vary significantly with increasing doses of unlabeled antibody. However, both the volume of distribution and the clearance rate from plasma increased significantly with increasing antibody dose. Uptake of antibody into tumor tissues obtained during laparotomy 8-9 days after administration varied between 0.00002% ID/g and 0.00127% ID/g. In five of seven patients, the tumor content of antibody was higher than that in adjacent normal tissue. Tumor-to-normal tissue ratios ranged from 0.8 to 10 (mean = 3.8 +/- 1.0). In general, the higher radioactivity(cpm)/g tumor was confirmed by both immunoperoxidase and autoradiography. Antibody 16.88 localizes in tumors after administration and may be considered for use in radioimmunotherapy trials.