Erythrocyte enzymes catalyze 1-nitropyrene and 3-nitrofluoranthene nitroreduction

Nitroarenes are environmental contaminants produced during incomplete combustion processes. Nitroreduction, the most important pathway of nitroarene toxification, occurs mainly in the liver and intestine. In the present study, we show that human red cells may also possess the metabolic competence to reduce 1-nitropyrene (NP) and 3-nitrofluoranthene (NF), the nitroarenes chosen as model compounds, to their corresponding amino derivatives, 1-aminopyrene (AP) and 3-aminofluoranthene (AF). The requirement of the cofactor couple NADH/FMN suggests that erythrocyte nitroreductase activity occurs via one electron transfer. The presence of oxygen strongly inhibited the haemolysate-catalyzed nitroarene reduction, whether measured as amine formation or nitroarene disappearance. Intermediate reactive species, that bind covalently to haemoglobin and/or other erythrocyte proteins, are formed during nitroreduction catalyzed by human haemolysate. In fact, the reduced metabolites AP and AF were released after mild acid hydrolysis of red cell proteins exposed to NP and NF, thus suggesting that sulphinamide adducts have been formed.

A non-isothermal bioreactor utilizing immobilized baker's-yeast cells: a study of the effect on invertase activity

The behaviour of the enzyme invertase, located on the cell wall of baker's-yeast cells and entrapped in a gelatin membrane, was studied under isothermal and non-isothermal conditions. The reaction rate linearly increased with the applied transmembrane temperature gradient, with reference either to the average temperature or to the temperature on the warm side of the catalytic membrane. These results were obtained both when the bioreactor was operated under conditions of closed volumes and when the substrate-containing solutions are recirculated. The mathematical relationships have been elaborated between the temperatures read in the working solutions and those on the two faces of the catalytic membrane. Since the temperature difference across the membrane is smaller than that indicated by the thermocouples, the observed effects are greater than expected. The potential advantages of the use of a non-isothermal bioreactor in processes of industrial interest are discussed.

Pyrrolo[2,1-c][1,4]benzothiazines: synthesis, structure-activity relationships, molecular modeling studies, and cardiovascular activity

The synthesis and pharmacological evaluation of a series of pyrrolo[1,4]benzothiazine derivatives are described. These compounds, related to diltiazem, have been shown to be representative of a novel series of calcium channel antagonists. The IC50S for inhibition of [3H]nitrendipine binding calculated by radioreceptor assay on rat cortex and rat heart homogenates showed that some of the described compounds possess an affinity equal to or higher than those of the reference calcium antagonists verapamil and cis-(+)-diltiazem. Furthermore, the alteration of the benzothiazepinone system of diltiazem to the pyrrolo[1,4]benzothiazine system of the title compounds resulted in a clear-cut selectivity for cardiac over vascular tissue, as shown in functional studies. In fact comparison of calcium antagonist activity on guinea pig aorta strips with the negative inotropic activity, determined by using an isolated guinea pig left atrium, revealed that the compounds examined displayed higher selectivity than the reference standard, within a wide variation of data. A number of structure-activity relationship trends have been identified, and possible explanation is advanced in order to account for the observed differences in selectivity. Prerequisite for in vitro calcium channel-blocking activity is the presence of two pharmacophores, namely, the substitution at C-4 and the substitution on the pyrrole ring. Two of the tested compounds, 8b and 28a, were identified as potent calcium antagonists selective for cardiac over vascular tissue.

Establishment of human acute myelogenous leukemia lines secreting interleukin-1 beta in SCID mice

A reproducible in vivo model of human acute myelogenous leukemia (AML) was established in severe combined immunodeficient (SCID) mice. The AML-CL and AML-PS lines were originated from leukemic blasts purified respectively from the peripheral blood of a 27-year-old woman with previously untreated hyperleukocytotic AML and from the bone marrow of a 61-year-old man during the third leukemic relapse. The 2 lines were maintained and serially transplanted i.p. in SCID mice. AML-PS and AML-CL produced ascitogenous gross tumors after approximately 4 and 6 weeks, respectively, and all mice died within 6-8 weeks. Microscopic evaluation of different organs at autopsy showed massive involvement of bone marrow, liver and spleen, though with differences in the tumor burdens for the 2 lines (AML-CL > AML-PS). Flow cytometric analysis documented the spread of leukemic cells to bone marrow, peripheral blood and spleen. AML-PS and AML-CL cells show an immunophenotypic profile (CD13+, CD33+) and cytogenetic findings similar to freshly isolated blasts. Interleukin-1 beta (IL-1 beta) gene expression was observed by Northern blot analysis in leukemic cells from AML-CL and AML-PS SCID mice. After 24 hr of culture both lines released IL-1 beta in culture supernatants. High levels of circulating IL-1 beta were secreted in plasma of tumor-bearing mice. This AML-SCID murine model could contribute to an understanding of the mechanisms of AML growth in vivo and the possible role of the autocrine production of IL-1 beta in promoting cell growth.

DNA ploidy, proliferative index, and epidermal growth factor receptor: expression and prognosis in patients with gastric cancers

BACKGROUND

The 5-year survival rate of patients with stomach cancer is usually around 20%. The clinico-pathological features that are presently used to assess patient prognosis are not sufficient to define gastric tumor behavior. Therefore, an accurate analysis of different biological characteristics of gastric cancer cells could allow the course of disease to be predicted and may help to improve treatment strategies.

EXPERIMENTAL DESIGN

The prognostic values of DNA ploidy, proliferative activity and epidermal growth factor receptor (EGF-R) expression were studied in gastric tumors from a series of 63 patients. DNA ploidy and proliferative activity, evaluated in terms of DNA index (DI) and proliferative index (PI), respectively, were determined by flow cytometry on paraffin-embedded tumor tissues. EGF-R expression was detected by immunohistochemistry on paraffin-embedded tumor sections of the same specimens. The clinico-pathological and the biological parameters were then correlated, and the patients overall survival was calculated using a chi-square test and the Kaplan-Meier method.

RESULTS

DNA ploidy abnormal cell clones were found in 44% of cases (median DI = 1.4, range 1.04-2.5). Aneuploid tumors showed high PI more frequently than diploids (71% versus 36%, p = 0.01). The analysis of the expression of EGF-R revealed that 88% of aneuploid tumors were positive for receptor expression. On the contrary, diploid tumors showed the presence of EGF-R only in 56% of cases (p = 0.01). DI, PI, and EGF-R expression were not related to histological grade. Conversely, the three biological parameters were significantly correlated to clinical stage and tumor invasion. The Kaplan-Meier survival curves showed a 73% 5-year survival rate in patients with diploid tumors whereas only 33% of patients with aneuploid lesions had a good prognosis (p = 0.001).

CONCLUSIONS

We demonstrate that DNA ploidy, PI, and EGF-R expression are closely related to some pathological and clinical characteristics in gastric cancer. The close relationship between aneuploidy, EGF-R positive expression, node involvement, and tumor invasion suggests that these parameters may be indicators of high malignancy. Finally, the results also show that aneuploidy and EGF-R-positive expression are indicative of a worse prognosis in gastric cancer patients. The study of these parameters might allow a more accurate stratification of patients, so that a targeted therapeutic protocol may be defined.

Inhibition of angiogenesis and murine hemangioma growth by batimastat, a synthetic inhibitor of matrix metalloproteinases

BACKGROUND

The importance of matrix metalloproteinases in angiogenesis, tumor growth, and metastasis is well known. However, little is known about the role of matrix metalloproteinases in the formation of hemangiomas and about the possible therapeutic use of matrix metalloproteinase inhibitors in aggressive vascular tumors.

PURPOSE

To study the role of matrix metalloproteinase in vascular tumors, we tested the antineoplastic activity of a synthetic inhibitor of matrix metalloproteinases, batimastat, on an experimental model of hemangioma, formed by murine endothelioma cells transformed by polyoma middle-T oncogene (eEnd.1).

METHODS

The effect of batimastat was studied in vivo on the formation of hemorrhaging, cavernous hemangiomas by eEnd.1 endothelioma cells injected subcutaneously in nude mice and on the angiogenic response induced by an endothelioma cell supernatant embedded in a pellet of reconstituted basement membrane (Matrigel). The effect of batimastat was investigated in vitro on endothelial cell proliferation, motility, and invasion of a layer of Matrigel.

RESULTS

Daily treatment with batimastat (30, 3, and 0.3 mg/kg at the site of eEnd.1 cell injection) inhibited tumor growth, with increased doubling time. The carboxamide derivative of batimastat, BB-374, a poor inhibitor of matrix metalloproteinase activity, was less active in reducing hemangioma growth. Histologic analysis of treated tumors indicated a reduction in the size of blood-filled spaces and in hemorrhage. Batimastat also inhibited the angiogenic response induced by cultured eEnd.1 endothelioma cell supernatant embedded in a pellet of Matrigel. Batimastat significantly inhibited endothelial cell invasion in vitro through a layer of Matrigel, but it showed no direct cytotoxic activity.

CONCLUSIONS

Batimastat reduces in vivo growth of experimental hemangiomas, most probably by blocking endothelial cell recruitment by the transformed cells or by interfering with cell organization in vascular structures.

IMPLICATIONS

These results confirm the importance of matrix metalloproteinase in endothelial cell recruitment that occurs in angiogenesis and in the formation of vascular tumors and suggest a therapeutic potential for synthetic matrix metalloproteinase inhibitors.

Involvement of the very late antigen 4 integrin on melanoma in interleukin 1-augmented experimental metastases

We have previously reported that treatment with interleukin 1 (IL-1) induced the augmentation of lung tumor colonies by a human melanoma in nude mice. Here we have investigated the involvement of the alpha 4 beta 1 integrin, the very late antigen 4 (VLA-4) in this augmentation. A375M melanoma cells expressed high levels of VLA-4 and preferentially adhered to a surface coated with vascular cell adhesion molecule 1 (VCAM-1), the ligand for VLA-4 on activated endothelial cells. This adhesion was inhibited by treating tumor cells with saturating concentrations of mAb to VLA-4. The production of lung colonies was significantly enhanced in nude mice given an injection of IL-1 before A375M melanoma cells. Immunoperoxidase staining showed that VCAM-1 could be expressed on lung vascular endothelium of mice in response to IL-1. Pretreatment of melanoma cells with a mAb to VLA-4 completely abrogated the IL-1-induced augmentation of lung colonies. Using two metastatic melanoma clones (clones 2/4 and 2/60) that expressed different levels of VLA-4, we found that only VLA-4-bearing cells adhered to a VCAM-1-coated surface and formed enhanced numbers of lung colonies in IL-1-treated nude mice. This augmentation was inhibited by pretreating the tumor cells with anti-VLA-4 mAb. These results demonstrate, in vivo, the functional involvement of VLA-4 on melanoma cells in IL-1-mediated lung colony augmentation, most probably involving the interaction of tumor cells with VCAM-1 on activated endothelial cells.

Erythrocyte-mediated toxification of 1,8-dinitropyrene. II. Covalent bind to erythrocyte-proteins

In the present study we have shown that erythrocyte-catalyzed 1,8-dinitropyrene reduction occurs via formation of reactive intermediate species, which bind covalently to haemoglobin and other erythrocyte proteins. In fact after mild-acid hydrolysis of lysate proteins exposed to DNP, the reduced metabolites, 1-amino-8-nitropyrene and 1,8-diaminopyrene, were released, thus indicating the formation of sulphinamide adducts to proteins. These results suggest that haemoglobin adduct biomonitoring would be a useful method of controlling exposure to nitroarene in persons at risk.

A comparative molecular field analysis model for 6-arylpyrrolo[2,1-d] [1,5]benzothiazepines binding selectively to the mitochondrial benzodiazepine receptor

A series of 42 6-arylpyrrolo[2,1-d][1,5]benzothiazepines, which we have recently described as selective ligands of the mitochondrial benzodiazepine receptor (MBR) (Fiorini I.; et al. J. Med. Chem. 1994, 37, 1427-1438), have been investigated using the comparative molecular field analysis (CoMFA) approach. The resulting 3D-QSAR model rationalizes the steric and electronic factors which modulate affinity to the MBR with a cross-validation standard error of 0.648 pIC50 unit. A set of seven novel pyrrolobenzothiazepine congeners has successively been synthesized and tested. The CoMFA model forecasts the binding affinity values of these new compounds with a prediction standard error of 0.536.

Early and late results of 100 consecutive total gastrectomies for cancer

The authors present a case study of 100 patients who underwent total gastrectomy out of a total of 376 patients submitted to surgery for gastric cancer between 1970 and 1992. The majority of the neoplasms were located in the middle third of the stomach with histological characteristics of an epithelial type in 92% of the cases, 8 of which were classified Stage IA, 6 Stage IB, 14 Stage II, 24 Stage IIIA, 25 Stage IIIB, and 15 at Stage IV. An R2 total gastrectomy, which included the distal 2-3 centimeters of the esophagus and the proximal 2-3 centimeters of the duodenum, combined with omentectomy and level 1 and 2 lymphadenectomy, was always performed. Thirty-four of the operations were extended and splenectomy was performed in 27 of these. Digestive continuity was obtained in 37 cases with an esophago-jejunostomy on a Roux-en-Y loop. Recanalization of the duodenum was accomplished in accordance with the Moricca technique in 32 cases and the Mouchet-Camey technique in 22 cases. Of the remaining 9, 5 underwent reconstructive surgery as described by Sweet-Allen, 2 as described by Nakayama, and the remaining 2 direct esophago-duodenostomy. The majority of the cases received total parenteral nutrition on the second postoperative day and this was maintained for the following eight days. Post-operative mortality, reported during the initial 30 days was 7%, overall morbidity 17%. A detailed protocol of clinical and diagnostic tests was established for follow-up studies conducted on a 4-month basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of the metastatic spread and growth of B16-BL6 murine melanoma by a synthetic matrix metalloproteinase inhibitor

The synthetic matrix metalloproteinase inhibitor batimastat was tested for its ability to inhibit growth and metastatic spread of the B16-BL6 murine melanoma in syngeneic C57BL/6N mice. Intraperitoneal administration of batimastat resulted in a significant inhibition in the number of lung colonies produced by B16-BL6 cells injected i.v. The effect of batimastat on spontaneous metastases was examined in mice inoculated in the hind footpad with B16-BL6 melanoma. The primary tumor was removed surgically after 26-28 days. Batimastat was administered twice a day from day 14 to day 28 (pre-surgery) or from day 26 to day 44 (post-surgery). With both protocols, the median number of lung metastases was not significantly affected, but there was a significant reduction in the weight of the metastases. Finally, the effect of batimastat was examined on s.c. growth of B16-BL6 melanoma. Batimastat administered daily, starting at day of tumor transplantation, resulted in a significant growth delay, whereas treatment starting at advanced stage tumor only reduced tumor growth marginally. Our results indicate that a matrix metalloproteinase inhibitor can not only prevent the colonization of secondary organs by B16-BL6 cells but also limit the growth of solid tumors.

Novel ligands specific for mitochondrial benzodiazepine receptors: 6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives. Synthesis, structure-activity relationships, and molecular modeling studies

A novel class of ligands specific for MBR receptors has been identified: 6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives. The majority of newly synthesized esters 37-64 as well as some intermediate ketones showed micro- or nanomolar affinity for [3H]PK 11195 binding inhibition. A SAR study on 42 compounds and a molecular modeling approach led to a preliminary structural selectivity profile: the 6,7-double bond, the carbamoyloxy, alcanoyloxy, and mesyloxy side chains at the 7-position, and the prospective chloro substitution at the 4-position seemed to be the most important structural features improving affinity. Therefore, 7-[(dimethylcarbamoyl)oxy]- and 7-acetoxy-4-chloro-6-phenylpyrrolo[2,1-d][1,5]benzothiazepine (43 and 57) were synthesized. With 7-[(dimethylcarbamoyl)oxy]-6-(p-methoxyphenyl)pyrrolo[2,1- d][1,5]benzothiazepine (65), these were the most promising compounds with IC50s of respectively 9, 8, and 9 nM, under conditions where PK 11195 had an IC50 of 2 nM.

Gastric cancer cell DNA content correlates with early and late results after gastrectomy

The DNA content of 59 adenocarcinomas of the stomach in patients who had undergone subtotal or total gastrectomy more than 5 years before was measured. The DNA measurements were done by flow cytometry performed on Propidium Iodide--stained cells disaggregated from paraffin-embedded tissues. Fifty-nine evaluable good quality histograms of DNA ploidy patterns were obtained. The Proliferative Index (PI) was determined in 35 cases. The remaining 24 cases didn't show a reliable reading histograms. Of the 59 tumors, 33 (56%) were diploid and 26 (44%) were aneuploid; 19 showed a high PI (> or = 3.8%) and 16 a lower one. A statistically significant difference was found between the two groups (diploid/aneuploid and low/high PI) compared to the prognostic values known as T, N and Stage. 65% of the T3-T4 cancers, 54% of the N1-N2 lesions and 58% of the stage III and IV were found to be aneuploid. 73.7% of the 19 tumors presenting high PI, showed an aneuploid pattern. A high PI was found in 71.4% of the T3-T4 tumors. 77.4% of patients of the diploid group (any stage) survived at 5 years against 36% of those presenting aneuploid patterns. Patients with PI > or = 3.8% showed a 42.1% 5-year survival rate. A 94.4% 5-year survival rate of diploid and early stage cancers was documented against a 33.5% of aneuploid and advanced stage cancers.

Continent perineal colostomy by transposition of gracilis muscles. Technical remarks and results in 14 cases

We herein present a study conducted on 14 patients presenting cancer of the lower rectum or of the anal canal (10 adenocarcinomas and 4 squamous-cell carcinomas) and submitted to the Miles abdominal perineal resection in which a new perineal sphincter was constructed.

PURPOSE

The aim of this study was to evaluate the efficacy of this new perineal sphincter constructed by transposing the gracilis muscles around an orthotopic colostomy in the attempt to avoid a permanent abdominal colostomy.

METHODS

In all cases both gracilis muscles were employed. The right one was placed along the posterior wall of the pelvis and fixed to the contralateral ischiatic tuberosity, creating a sling comparable to the levator ani muscles. The left gracilis was passed around the colon and attached to the ipsilateral or contralateral tuberosity according to its length, reconstructing a muscular ring. The entire procedure was performed in one step in nine cases and in more steps in the remaining five.

RESULTS

Of the 14 operated patients, 2 died of vascular disease and 1 developed necrosis of the colonic stump which required reconversion to an abdominal colostomy. Of the remaining 11 patients available for long-term evaluations, 8 showed adequate stool control. The remaining three manifested an incomplete level of continence. During the three-year follow-up period, all patients were evaluated by clinical examination, defecography, endoluminal ultrasonography, nuclear magnetic resonance, CT scan, and endoluminal manometry.

CONCLUSION

This neosphincter realizes an elastic stenosis responsible for an efficient level of continence. Best results are observed in the young and educated patients submitted to surgery in two steps. Contraindications to this surgery seem to be advanced cancer, old age, and obesity.

Correlation between positive CA 72-4 serum levels and lymph node involvement in patients with gastric carcinoma

CA 72-4 serum marker has been shown to be one of the most specific and sensitive markers for monitoring gastric cancer. In the present study we evaluated the correlation between CA 72-4, CA 19-9 and CEA serum levels, and tumor size and lymph node involvement in gastric carcinoma patients. One-hundred sixty-one patients with primary or recurrent gastric carcinoma were studied. Elevated CA 72-4, CA 19-9, and CEA serum levels were found in 42.2%, 32.3% and 24.2%, respectively. As previously shown, the combination of CA 72-4 and CA 19-9 increased positive samples to 56.5%, while the addition of CEA did not further improve this percentage. Unlike what has been previously published, none of the markers showed a significant correlation with serosal involvement. In fact, elevated serum levels were observed for the three markers in a very low percentage of cases either in T1-T2N0 or T3-T4N0 patients. In contrast, CA 72-4 showed a highly significant correlation with lymph node involvement: T1-T4N0 patients had positive CA 72-4 levels in 5 out of 37 (13.5%), while T1-T4N1 in 12 out of 32 (37.5%), and T1-T4N2 in 20 out of 40 (50%) (p < 0.003). CA 19-9 and CEA serum levels were not significantly correlated. Since the presence of lymph node metastases is considered a negative prognostic factor, these results suggest that the measurement of CA 72-4 serum levels may be an important parameter in the diagnosis and clinical follow-up of patients with gastric carcinoma.

Interleukin 1 receptor antagonist inhibits the augmentation of metastasis induced by interleukin 1 or lipopolysaccharide in a human melanoma/nude mouse system

This study examined the ability of the recombinant human interleukin 1 receptor antagonist (IL-1ra) to block interleukin 1 (IL-1)-mediated experimental metastases from the A375M human melanoma. In vivo, IL-1ra administrated at concentrations > or = 200 times IL-1 significantly inhibited the increase in lung colonies induced by IL-1 in nude mice. The response to IL-1 was significantly inhibited when IL-1ra was administered simultaneously with or 1 to 3 h before IL-1. In vitro, the incubation of IL-1-activated endothelial cells with IL-1ra prevented the increase in adhesion of A375M melanoma cells. At the same experimental conditions, IL-1ra inhibited the augmented expression of the intracellular and vascular cell adhesion molecules 1 and E-selectin induced by IL-1 on endothelial cells. Lipopolysaccharide, an IL-1 inducer, increased the number of lung colonies in nude mice. IL-1ra injected with or 1 h after lipopolysaccharide inhibited this augmentation, suggesting a role for host-produced IL-1 in metastasis formation.

Human T-cell lymphoblastic lymphoma expressing the T-cell receptor gamma/delta established in immune-deficient (bg/nu/xid) mice

A small subgroup of human CD3-positive T-cell lymphoblastic lymphoma (T-LL) has been recently identified to express the T-cell receptor (TCR) gamma/delta heterodimer. Moreover peculiar clinical and histologic patterns of spleen and liver involvement have been associated with the TCR gamma/delta phenotype of tumor cells. In this paper we describe a human T-LL cell line (LL-DP) established in beige-nude-xid (BNX) mice, that by immunophenotype, molecular, and karyotype analyses, maintained most of the features of the patient. After serial transplants in BNX mice, LL-DP acquired quite a stable phenotype, producing a visible tumor in about 5 weeks in all the intravenously injected animals. The minimum number of transplanted cells that produce a tumor in all mice is 1 x 10(6). BNX mice bearing LL-DP lymphoma cells presented marked abdominal distension and splenomegaly. Diffuse lymphadenopathy with large tumor deposits in various lymph nodes that produce architectural effacement with a diffuse growth pattern was documented. The bone marrow was completely replaced, and spleen, liver, and kidneys were involved. Invasion of the central nervous system was leptomeningeal and perivascular. Overall this model might be useful for understanding mechanisms supporting lymphoma growth and progression as well as for testing new therapeutic strategies.

Benzothiazine and benzothiazepine derivatives: synthesis and preliminary biological evaluation

Several tricyclic benzothiazines and benzothiazepines have been synthesized by different intramolecular cyclization reactions. Their functionalization led to biologically active compounds. Some stereochemical aspects as well as biological responses have been outlined.

Matrigel promotes retinoblastoma cell growth in vitro and in vivo

Cells derived from retinoblastomas grow slowly in vitro and only very rarely form tumors in nude mice. Matrigel, a mixture of components normally found in basement membranes, promotes the growth of Y-79 and WERI-Rb1 retinoblastoma (Rb) cells when added to suspension cultures of the 2 Rb cell lines. It also substantially increases cell adhesion in vitro. Y-79 cells, seeded into a Matrigel matrix, form round colonies over a 3-week period similar to those of control, weakly metastatic murine melanoma cells. In vivo, s.c. co-injection of Matrigel with either Y-79 or WERI-Rb 1 cells into nude mice promotes retinoblastoma tumor formation. Transplantation of as few as 1,000 cells allows for xenografting under these conditions, while no tumors were observed in the absence of Matrigel, even at 10 x 10(6) cells/inoculum. The tumors produced have the expected morphology and express an mRNA for a highly specific retina/retinoblastoma marker protein, the interphotoreceptor retinoid-binding protein. Thus, the xenografts obtained maintain the original morphological and molecular characteristics of the injected cells and represent a useful model for in vivo studies of retinoblastoma growth and treatment.

Transfer of the ADA gene into human ADA-deficient T lymphocytes reconstitutes specific immune functions

Peripheral blood lymphocytes obtained from a patient affected by adenosine deaminase (ADA) deficiency and severe combined immunodeficiency were infected with a retroviral vector containing two copies of a human ADA minigene, and injected into bg/nu/xid (BNX) immunodeficient mice. Six to 10 weeks after injection, human T cells were cloned from the spleens of recipient animals and analyzed for proliferative potential, T-cell surface markers, expression of ADA activity, integration of retroviral sequences, T-cell receptor (TCR) beta gene rearrangement, and specificity of antigen recognition. Efficient gene transfer and expression restored proliferative potential in vitro and long-term survival in vivo. All clonable human T lymphocytes obtained from the spleen of recipient animals had high levels of vector-derived ADA enzyme activity and showed predominantly the CD4+ phenotype. Retroviral integrations and TCR-beta gene rearrangements demonstrated the presence of a variety of different clones in the spleens of recipient mice. Furthermore, the combined analyses of vector integration and TCR rearrangement provided evidence that a circulating progenitor cell was transduced by the retroviral vector, giving rise to different and functional TCRs. Evaluation of antigen-specificity demonstrated both alloreactive and foreign antigen specific immune responses. These results suggest that restoration of enzyme activity in human ADA-deficient peripheral blood T cells by retroviral-mediated ADA gene transfer allows in vivo survival and reconstitution of specific immune functions. Therefore, retroviral vector-mediated gene transfer into circulating mononuclear cells could be successful not only in maintaining the metabolic homeostasis, but also for the development of a functional immune repertoire. This is a fundamental prerequisite for the usage of genetically engineered peripheral blood lymphocytes for somatic cell gene therapy of ADA deficiency.