Biotechnology therapeutics最新文献

RRR-alpha-tocopheryl succinate (vitamin E succinate) was studied for its effects on interleukin-2 (IL-2) production by chicken splenic derived T lymphocytes and murine EL-4 thymic lymphoma cells. Supernatants from 0.1 microgram/mL vitamin E succinate-supplemented chicken splenic T cell cultures exhibited 42-72% enhanced IL-2 production over vehicle controls when tested in a chicken T cell blast bioassay. Supplementation of chicken splenic T lymphocyte cultures with butylated hydroxyanisole (BHT) and butylated hydroxytoluene (BHA) also induced elevated levels of IL-2, suggesting a role for antioxidants in IL-2 production by avian splenic T lymphocytes. Supernatants from vitamin E succinate-supplemented murine EL-4 cells (0.1 microgram/mL vitamin E succinate) induced 52-75% increased levels of IL-2 when compared to supernatants from vehicle controls when tested using a murine, IL-2-dependent CTLL-2 bioassay. IL-2 production by EL-4 cells was not enhanced by treatments with BHT, BHA, or Trolox, suggesting that vitamin E succinate-induced IL-2 production by EL-4 cells may involve a mechanism other than antioxidant effects. Vitamin E succinate plus suboptimal levels of the protein kinase C (PKC) activator phorbol myristate acetate (PMA) induced the highest levels of IL-2 by EL-4 cells. The studies provide evidence that vitamin E succinate can directly potentiate either the production or release of IL-2 from avian splenocytes and murine EL-4 cells.

There is no effective therapy available for stage D2 prostate cancer once patients become refractory to hormonal therapy. In a pilot study, we treated 17 patients with hormone-refractory stage D2 prostate cancer using autolymphocyte therapy, an outpatient form of adoptive immunotherapy in which patients are treated with autologous T cells that have been activated ex vivo. Feasibility and safety were documented. Transient PSA reductions up to 66% were noted, suggesting biological activity. Further studies to test the safety and efficacy of autolymphocyte therapy in the treatment of prostate cancer are warranted.

The complete murine prothymosin alpha molecule (110 residues) except for the N-terminal methionine deduced from the cloned cDNA has been synthesized by a solid-phase method. Peptide synthesis was performed manually by the stepwise solid-phase method using the base-labile Fmoc group for protecting the alpha-amino group. The peptide was assembled on a p-alkoxybenzyl alcohol resin. After the last coupling step, the Fmoc group was removed with 50% piperidine in DMF. The peptide resin was treated with thioanisole-o-cresol in TFA, and then purified by gel filtration, ion-exchange column chromatography and high-performance liquid chromatography. A 2.9-mg sample of a highly purified peptide was finally obtained. The overall yield of the synthesis was less than 1%, based on the amino acid content of the starting Fmoc-Asp (OtBu)-resin. The synthetic peptide was found to have a restoring activity on low-E-rosette-forming lymphocytes after incubation of peripheral blood from uremic patients with the synthetic peptide. This peptide exhibited far stronger restoring effect than that of our synthetic thymosin alpha 1.

Anesthesized male rabbits having a resting mean arterial pressure of 81 +/- 4 mm Hg and superior mesenteric artery blood flow of 91 +/- 7 mL min-1 were subjected to 60 min of splanchnic ischemia followed by 60 min of reperfusion. Upon reperfusion, mean arterial pressure fell. Splanchnic blood flow also decreased but not in parallel with blood pressure; consequently, vascular resistance was increased over the reperfusion period. This increase in splanchnic vascular resistance was not affected by intravenous t-PA (0.5 mg kg-1 + 5 mg kg-1 hr-1) for 30 min prior to and throughout the reperfusion period or by intravenous L-NAME (1 mg kg-1 x 2). However, intravenous infusions of TGF-beta (18 or 54 micrograms kg-1) at the time of reperfusion dose dependently attenuated the increases in vascular resistance (p < 0.05). This effect of TGF-beta was enhanced by coadministration of t-PA and inhibited by the coadministration of L-NAME. We propose that the effects of TGF-beta are ultimately mediated via nitric oxide release, and conclude that this may be useful therapy for the prevention of reperfusion-associated injury following surgery or as an adjunct to thrombolytic therapy.

Human leukocyte-derived interferon alfa-n3 (Alferon N Injection) is purified to very high specific activity over a murine immunoaffinity column specific for human interferon alpha. Trace amounts of murine immunoglobulin copurify with the interferon alfa-n3. Three populations of individuals were studied for the development of human anto-murine antibodies (HAMA), that is, normal donors, Condylomata acuminata patients receiving interferon alfa-n3, and Condylomata acuminata patients receiving placebo. High and variable endogenous levels of HAMA were observed in all three populations. The same relative increase in HAMA was seen in the placebo as in the interferon alfa-n3 treatment groups. The data demonstrate that intralesional injection of the interferon alfa-n3 did not induce the development of HAMA.

Two deacetyl-thymosin alpha 1 analogues containing Phe or Phe(4F) at position 21 were synthesized by the manual solid-phase method and their immunological effects on the low E-rosette-forming lymphocytes of uremic patients were studied. Fluorination of the p-position of Phe21 resulted in a marked restorative effect on the low E-rosette-forming lymphocytes of uremic patients compared with that of [Phe21]deacetyl-thymosin alpha 1. The synthetic [Phe21]deacetyl-thymosin alpha 1 was approximately equal in potency to our synthetic deacetyl-thymosin alpha 1 in uremic patients.

Twenty-four patients with histologically proven metastatic malignant melanoma were included in a phase II trial of recombinant IL-2 (rIL-2, RU 49637). Twenty million international units (IU)/m2/day were given by continuous intravenous infusion on days 1 to 5, 15 to 18, and 29 to 31, and then monthly for 5 days until disease progression or major intolerance developed. All patients were evaluable for response and toxicity. Toxicity was consistent with one case of myocardial ischemia, 13 cases of grade III and IV hypotension, and 15 cases of proven sepsis. There were 8 objective responses: 4 of them were of short duration as they were observed on day 31 only. An activation of the immune system was detected in all patients. It was demonstrated by an increase in lymphocyte populations, especially in activated NK cells. A tendency for higher numbers of cytotoxic cells was found in patients with objective tumor responses. These results indicate a role for rIL-2 RU 49637 in treating patients with metastatic malignant melanoma. However, further trials are required to determine its optimal dosage and schedule of administration.

The positive effect of an immunotherapy using tumor-associated antigens or tumor cells of ovarian carcinomas has not yet been proven. Although many unique tumor-associated antigens have been described and a tumor rejection could be seen in occasional cases, the failure of the immune system to destroy tumor cells is not clearly understood. An alternative approach is to initiate the idiotypic network utilizing antibodies (Ab1 or 2) against a tumor-associated antigen, which induces the production of anti-idiotypic-antibodies (Ab2 beta), mimicking the "internal image" of the tumor-associated antigen. These antibodies are able to induce a specific antitumor immunity in two ways: (1) the Ab2 can present the critical epitope in a different way and so modulates the immune system, or (2) it can induce the production of an Ab3, which by itself binds to the tumor antigen. Our first results on 22 patients with advanced ovarian carcinomas show that the induction of an anti-idiotypic antibody (Ab2 beta) against OC 125 mimicking the TAA Class III CA 125 leads to a prolongation of the survival rate also for extended stages. We see a beneficial role of the induction of the idiotypic network against a tumor-associated antigen showing delayed clinical courses of the disease after vaccination of the patients with antibody fragments of the OC 125.

Circumsporozoite proteins from the malaria parasites Plasmodium falciparum and Plasmodium vivax were expressed at high levels in the yeast Saccharomyces cerevisiae. Recombinant proteins varied both in length and in number of the natural amino acid repeat motifs. The proteins were purified and used to immunize mice, guinea pigs, and rabbits. Novel muramyl peptide adjuvants were used that increased the immune response as measured by ELISA assays, indirect immunofluorescence of fixed sporozoites, and the invasion of cultured liver cells by live sporozoites. These results suggest that an improved humoral response to recombinant circumsporozoite vaccines might be achieved by varying the design of the recombinant protein and by the use of novel adjuvant systems.

Apocynin (4-hydroxy-3-methoxy-acetophenone) is a potent and selective inhibitor of neutrophil oxyradical production. The mechanism of action involves metabolic activation in a (myelo)-peroxidase-dependent reaction. The reaction product(s) prevent(s) the assembly of the superoxide anion-generating NADPH:O2 oxidoreductase by conjugation to essential thiol groups. Different neutrophil functions that are essential to their bactericidal activity, however, remain intact. When administered orally a potent anti-inflammatory activity was found in rats with experimentally induced local or systemic inflammation.