Enhancement of human allogeneic cytotoxic responses by interferons

The ability of exogenous interferons (IFN) to modify human allogeneic cytotoxic responses was studied. alpha- and beta-, and gamma-IFN, enhanced the cytotoxic responses if added at early phases of the cultures. The effect of exogenous IFN was abrogated if antibody directed against the specific IFN were present in the cultures. Normal allogeneic cytotoxic responses were abrogated in the presence of any of the anti-IFN antibodies. This inhibition could be overcome if exogenous IFN of any type (alpha, beta, or gamma) was added in excess to the cultures. IFN participate in the generation of allogeneic cytotoxic lymphocytes during mixed lymphocyte culture. It seems that each of the types of IFN supports the generation of cytotoxic responses independently of the presence of an IFN of another type.     

Recombinant human serum albumin

Human serum albumin (HSA) is responsible for 80% of the colloid osmotic pressure of plasma (25-33 mmHg). Its main clinical use is in maintaining colloid oncotic pressure and increasing circulating plasma volume with the typical dosage in excess of 10 g per dose. HSA is isolated by fractionating human plasma, which entails possible contamination by viruses or prions. Recombinant HSA (rHSA) has been successfully produced using a methylotrophic yeast, Pichia pastoris. Due to the fact that the clinical usage of HSA infusion often exceeds 10 g, rHSA preparation requires a high level of purity. rHSA purified by means of Streamline technology is identical to plasma-derived HSA (pdHSA) with no detectable mannan component from P. pastoris. The structural and functional properties of rHSA are similar to those of pdHSA. Preclinical and clinical trials have confirmed the safety and efficacy of using this rHSA preparation in different disease conditions, such as hemorrhagic shock, cirrhosis with ascites, and other critical clinical conditions related to plasma volume and oncotic pressure. In addition to its use as a plasma expander, rHSA has great potential as a biomaterial for other medical and pharmaceutically related applications.     

Novel plant-derived recombinant human interferons with broad spectrum antiviral activity

Type I interferons (IFNs) are potent mediators of the innate immune response to viral infection. IFNs released from infected cells bind to a receptor (IFNAR) on neighboring cells, triggering signaling cascades that limit further infection. Subtle variations in amino acids can alter IFNAR binding and signaling outcomes. We used a new gene crossbreeding method to generate hybrid, type I human IFNs with enhanced antiviral activity against four dissimilar, highly pathogenic viruses. Approximately 1400 novel IFN genes were expressed in plants, and the resultant IFN proteins were screened for antiviral activity. Comparing the gene sequences of a final set of 12 potent IFNs to those of parent genes revealed strong selection pressures at numerous amino acids. Using three-dimensional models based on a recently solved experimental structure of IFN bound to IFNAR, we show that many but not all of the amino acids that were highly selected for are predicted to improve receptor binding.     

Novel plant-derived recombinant human interferons with broad spectrum antiviral activity

Type I interferons (IFNs) are potent mediators of the innate immune response to viral infection. IFNs released from infected cells bind to a receptor (IFNAR) on neighboring cells, triggering signaling cascades that limit further infection. Subtle variations in amino acids can alter IFNAR binding and signaling outcomes. We used a new gene crossbreeding method to generate hybrid, type I human IFNs with enhanced antiviral activity against four dissimilar, highly pathogenic viruses. Approximately 1400 novel IFN genes were expressed in plants, and the resultant IFN proteins were screened for antiviral activity. Comparing the gene sequences of a final set of 12 potent IFNs to those of parent genes revealed strong selection pressures at numerous amino acids. Using three-dimensional models based on a recently solved experimental structure of IFN bound to IFNAR, we show that many but not all of the amino acids that were highly selected for are predicted to improve receptor binding.     

Recombinant human activated protein C

This review will summarise the relevant pathophysiology of sepsis, the rationale for treatment with recombinant human activated protein C and the evidence for and against its use, and will provide evidence-based recommendations for its administration.     

Potentiation of interferon action by mixtures of recombinant DNA-derived human interferons

Natural and essentially pure recombinant DNA-derived HuIFN-alpha and HuIFN-gamma were examined for their relative abilities to potentiate interferon action. Potentiation of human interferon's antiviral and antiproliferative activities were studied. The essentially pure recombinant DNA-derived human interferons were found to be as effective in their potentiating interactions as their natural counterparts. The results demonstrate that it is the human interferons themselves which interact to potentiate human interferon's varied activities.     

骨形态发生蛋白在大肠杆菌中表达的研究

目的骨形态发生蛋白（bone morphogenetic protein,BMP）是一种具有诱导活性的酸性糖蛋白,在组织工程研究和临床应用上需求量较大,BMP-2在组织中含量较微,利用基因工程方法生产重组BMP-2显得尤为重要。方法本研究根据人骨形态发生蛋白（bone morphogenetic protein,BMP）基因序列设计出引物,以克隆载体质粒pBR322-BMP-2为模板,得到BMP-2基因并重组入原核表达载体pGEX-4T-1中,将经酶切和测序鉴定正确的重组质粒转化大肠杆菌DH5α,用IPTG诱导表达,表达产物经SDS-PAGE鉴定并用Western bluing检测。结果SDS—PAGE显示,得到40KD的目的蛋白,表达量可达菌体总蛋白的15．2％,Western bloting检测表明,抗BMP-2单抗可与相对分子量40KD大小的电泳条带发生特异性反应,从而证明表达产物具有目的蛋白构型。结论本研究为进一步研究利用原核表达系统大量生产BMP-2打下基础。     

Recombinant interferons alpha and gamma: comparative antiviral activity and synergistic interaction in encephalomyocarditis virus infection of mice

The antiviral properties of 2 recombinant DNA-produced interferons, a human hybrid interferon alpha that is active in mice and a murine interferon gamma, were examined in the treatment of mice infected with encephalomyocarditis virus. A single dose of interferon alpha induced a protective state in mice more rapidly than did interferon gamma, but the activity of the latter was more long lasting. When interferon and virus were administered 6 h apart, either intraperitoneally or intravenously, interferons alpha and gamma were equally effective. However, this was not the case when the routes of treatment and infection were different. Interferon alpha showed somewhat reduced activity when the route of administration (intravenous) was different from the route of virus challenge (intraperitoneal) while interferon gamma showed very little activity when tested in this manner. When interferons alpha and gamma were administered in combination to mice, a marked synergistic antiviral effect was observed.     

重组人促红细胞生成素与神经疾病

重组人促红细胞生成素(recombinant human erythropoi-etin,rhEPO)目前在临床上主要用于治疗各种原因引起的贫血。大量研究表明,rhEPO除具有造血调节活性以外,还具有强大的神经保护作用。rhEPO对创伤性脑损伤、脑卒中、胎儿和新生儿脑损伤、脊髓损伤、神经病理性疼痛、精神分裂症、视神经损伤等多种神经疾病具有潜在的临床应用前景。该文就近年来rhEPO对以上各种神经疾病作用研究的最新进展进行了全面综述。     

Recombinant expression of human mannan-binding lectin

Mannan-binding lectin (MBL) constitutes an important part of the innate immune defence by effecting the deposition of complement on microbial surfaces. MBL deficiency is among the most common primary immunodeficiencies and is associated with recurrent infections and symptoms of poor immune complex clearance. Plasma-derived MBL has been used in reconstitution therapy but concerns over viral contamination and production capacity point to recombinant MBL (rMBL) as a future source of this protein for clinical use. Natural human MBL is an oligomer of up to 18 identical polypeptide chains. The synthesis of rMBL has been accomplished in several mammalian cell lines, however, the recombinant protein differed structurally from natural MBL. In this, study we compare rMBL produced in myeloma cells, Chinese hamster ovary (CHO) cells, human hepatocytes, and human embryonic kidney (HEK) cells. We report that rMBL structurally and functionally similar to natural MBL can be obtained through synthesis in the human embryonic kidney cells followed by selective carbohydrate affinity chromatography.     

Recombinant human antithrombin III: rhATIII

GTC Biotherapeutics (formerly Genzyme Transgenics Corporation) is developing a transgenic form of antithrombin III known as recombinant human antithrombin III [rhATIII]. It is produced by inserting human DNA into the cells of goats so that the targeted protein is excreted in the milk of the female offspring. The transgenic goats have been cloned in collaboration with the Louisiana State University Agriculture Center. GTC Biotherapeutics is conducting clinical trials of rhATIII in coagulation disorders. rhATIII is believed to be both safer and more cost-effective than the currently available plasma-derived product. rhATIII is also being investigated in cancer and acute lung injury. Genzyme Transgenics Corporation, originally a subsidiary of Genzyme Corporation, changed its name to GTC Biotherapeutics in June 2002; it is no longer a subsidiary of Genzyme Corporation. GTC Biotherapeutics is seeking partners for the commercialisation of rhATIII. Restructuring of GTC Biotherapeutics to support its commercialisation programmes was announced in February 2004. Genzyme Transgenics Corporation was developing rhATIII in association with Genzyme General (Genzyme Corporation) in the ATIII LLC joint venture, but in November 2000 a letter of intent was signed for the reacquisition of the rights by Genzyme Transgenics Corporation. It was announced in February 2001 that this reacquisition was not going to be completed and that the development of rhATIII was to continue with ATIII LLC. However, in July 2001, Genzyme Transgenics Corporation reacquired all the rights in the transgenic antithrombin III programme. SMI Genzyme Ltd, a joint venture between Sumitomo Metal Industries, Japan, and Genzyme Transgenics Corporation, USA, was set up to fund development of transgenic antithrombin III in Asia. However, in October 2000, Genzyme Transgenics Corporation reacquired, from Sumitomo Metal Industries, the rights to its technology for production of medicines from milk in 18 Asian countries, including Japan. The 10-year-old joint venture, SMI Genzyme Ltd, was dissolved. In June 2002, GTC Biotherapeutics estimated the current market size for plasma ATIII products to be approximately $US250 million - of which sales in Europe amounted to $US110 million, Japan $US130 million and the US $US10 million.     

Permeability modulation of human intestinal Caco-2 cell monolayers by interferons.

We investigated the effects of interferon-β (IFN-β) and IFN-γ on the drug efflux activity of the human intestinal Caco-2 cell line, expressing the P-glycoprotein (P-gp) on the apical membrane. The cells grown on Transwell plates were pretreated with 1000 U/ml IFN-β, IFN-γ or a combination of both for 3 days, and then the transepithelial electrical resistance (TEER) and the vectorial transport of rhodamine-123 (Rho-123) across the cell monolayers were evaluated. Exposure to IFN-γ reduced substantially the TEER, but the effect of IFN-β was minimal? The apparent permeability of Rho-123 in both the basolateral-to-apical and apical-to-basolateral directions was significantly increased by IFN-γ but scarcely by IFN-β. The combination of IFN-γ and IFN-β showed similar effects to IFN-γ alone. Meanwhile, the cellular uptake of Rho-123 from the apical side was not affected by any IFN treatment. The uptake level was increased approximately three times in the presence of verapamil, a P-gp inhibitor, and the increased level was not affected by any IFN treatment, indicating that the efflux activity mediated by P-gp in the monolayers is not altered by these cytokines. Taken together, these results suggest that IFNs modulate the permeability of Caco-2 monolayer through effect on paracellular transport rather than effect on P-gp activity.     

Recombinant human thyrotropins of the twenty-first century

In recent years, many new recombinant protein therapeutics have been developed and tested in clinical trials [1]. Current and future clinical uses of recombinant human thyroid-stimulating hormone (rhTSH; Thyrogen^?, Genzyme) in thyroid diseases are discussed in the review published in this issue of Expert Opinion on Pharmacotherapy [2]. As Thyrogen is a wild-type rhTSH produced in Chinese hamster ovary cells, it has relatively low affinity to the human TSH receptor. Such low affinity and weak intrinsic bioactivity of rhTSH, compared to the bovine or rodent TSH, may help to explain the results of several studies indicating limited clinical efficacy of Thyrogen. TSH analogues with largely increased receptor affinity, potency and efficacy, are expected to provide not only more effective than currently used diagnostic methods, but should also serve as indispensable second-generation thyrotropins for the diagnosis and treatment of thyroid carcinomas with a largely limited number of TSH receptors.     

Recombinant human thyrotropins of the twenty-first century

In recent years, many new recombinant protein therapeutics have been developed and tested in clinical trials [1]. Current and future clinical uses of recombinant human thyroid-stimulating hormone (rhTSH; Thyrogen, Genzyme) in thyroid diseases are discussed in the review published in this issue of Expert Opinion on Pharmacotherapy [2]. As Thyrogen is a wild-type rhTSH produced in Chinese hamster ovary cells, it has relatively low affinity to the human TSH receptor. Such low affinity and weak intrinsic bioactivity of rhTSH, compared to the bovine or rodent TSH, may help to explain the results of several studies indicating limited clinical efficacy of Thyrogen. TSH analogues with largely increased receptor affinity, potency and efficacy, are expected to provide not only more effective than currently used diagnostic methods, but should also serve as indispensable second-generation thyrotropins for the diagnosis and treatment of thyroid carcinomas with a largely limited number of TSH receptors.     

The new alpha interferons

Alpha interferons are biological response modifiers that regulate immune function, slow cell proliferation, and inhibit virus replication. Large supplies of purified preparations are now available for clinical trials. Common toxicity includes an influenza-like syndrome to which tolerance occurs after several doses, and chronic fatigue and anorexia that may be dose-limiting. Myelosuppression is mild. Alpha interferons have established clinical activity against several human cancers, including melanoma, Kaposi's sarcoma, multiple myeloma, non-Hodgkin's lymphoma, hairy cell leukemia, and renal cell carcinoma. These data and alpha interferon nomenclature are summarized in table form. Intranasal alpha interferon is effective in prophylaxis of common viral upper respiratory tract infections, although toxicity in long-term use is prohibitive. Short-term administration to high risk populations may be most useful. Optimal doses and schedules need to be determined for all indications.     

Clinical uses of interferons

Interferons were first described by Isaacs & Lindenmann working at the National Institute for Medical Research, Mill Hill in 1957 [ 1 ]. Thus, the fiftieth year of their discovery is being celebrated this year at Oxford in a meeting of the International Society for Interferon and Cytokine Research. This then is an appropriate time to review the clinical applications of the interferons. To accomplish this coherently it is necessary also to review briefly what led to the discovery of interferons, why their clinical applications were so slow in coming, and the impact of interferon research on the biomedical sciences.     

The antiproliferative effects associated with vincristine and human interferons in experimental in vitro systems

Cytotoxic potential of suboptimal doses of vincristine associated with human interferon was studied in two cell lines of tumoral origin, as compared to the action of or gamma type interferon preparations. Results show that the vincristine cytotoxic effect may be synergistically augmented in both culture types by simultaneous interferon administration.