Challenges related to the immunogenicity of parenteral recombinant proteins: Underlying mechanisms and new approaches to overcome it

Immune response elicited by therapeutic proteins is an important safety and efficacy issue for regulatory agencies, drug manufacturers, clinicians, and patients. Administration of therapeutic proteins can potentially induce the production of anti-drug antibodies or cell-mediated immune responses. At first, it was speculated that the immunogenicity is related to the non-human origin of these proteins. Later on, it was confirmed that the human proteins may also show immunogenicity. In this review article, we will focus on a number of factors, which play crucial roles in the human protein immunogenicity. These factors are related to the patient's status (or intrinsic properties) and molecular characteristics of the therapeutic protein's (or extrinsic properties). Furthermore, we will discuss available in silico, in vitro, and in vivo methods for the prediction of sequences, which may generate an immune response following parenteral administration of these proteins. In summary, nowadays, it is possible for drug manufacturers to evaluate the risk of immunogenicity of therapeutic proteins and implement a management plan to overcome the problems prior to proceeding to human clinical trials.     

点突变p53及其抗原肽重组痘苗病毒抗肿瘤效应的比较研究

目的　比较点突变p5 3及其抗原肽重组痘苗病毒诱导的抗瘤免疫反应 ,为重组抗原疫苗用于肿瘤免疫治疗提供实验依据。方法　以人 135位Cys→Tyr点突变 p5 3为肿瘤相关抗原模型 ,观察以表达该点突变 p5 3蛋白的重组痘苗病毒rVV p5 3FL与表达包含该点突变抗原肽 p5 312 5 14 5的重组痘苗病毒rVV p5 3M 所诱导的CTL及对荷瘤Balb/c小鼠的免疫保护和治疗作用。结果　rVV p5 3FL和rVV p5 3M 均能诱导以CD8 T细胞为主的特异性CTL。用rVV p5 3FL与rVV p5 3M 免疫小鼠后 ,接种致死剂量的P815 mp5 3细胞 ,能保护部分小鼠免遭致死剂量肿瘤细胞的攻击。小鼠接种致死剂量的肿瘤细胞后 ,以rVV p5 3FL与rVV p5 3M 治疗荷瘤小鼠 ,可使小鼠平均存活时间显著延长。两种疫苗的抗瘤效应无明显区别。结论　来源于突变p5 3的抗原肽重组疫苗 ,可代替抗原大分子应用于肿瘤的免疫防治     

Comparison of the immunogenicity of reduced doses of two recombinant DNA hepatitis B vaccines in New Zealand children

A group of 201 hepatitis B virus (HBV) sero-negative children 1-12 years of age received either three 2 micrograms doses of Merck Sharp and Dohme (MSD) or Smith Kline and French (SKF) recombinant DNA (rDNA) hepatitis B vaccine I.M. at monthly intervals. Each recipient was tested 4-6 weeks later for antibody to hepatitis B surface antigen (anti-HBs) by enzyme immunoassay (EIA) and radioimmunoassay (RIA). Ninety-six 4-5-year-old children, given 2 micrograms doses of a plasma-derived vaccine (MSD, H-B-Vax) I.M. at 0, 1, 2 months, were tested at the same time with the same assays for comparison. Anti-HBs responses and geometric mean titres (GMT) were significantly higher with the MSDrDNA vaccine (96% and 338.9 IU/liter) than with the SKF/r DNA vaccine (82.3% and 69.4 IU/liter). We conclude that for the protection of young children, 2 micrograms doses of the MSD rDNA hepatitis B vaccine may be used under similar circumstances in which 2 micrograms of the MSD plasma-derived vaccine was used. Further studies are needed before the other rDNA hepatitis B vaccine may be used in lower than the 10 micrograms dose recommended in children.     

Characteristics of alpha/beta interferon induction after infection of murine fibroblasts with wild-type and mutant alphaviruses

We examined the characteristics of interferon alpha/beta (IFN-α/β) induction after alphavirus or control Sendai virus (SeV) infection of murine fibroblasts (MEFs). As expected, SeV infection of wild-type (wt) MEFs resulted in strong dimerization of IRF3 and the production of high levels of IFN-α/β. In contrast, infection of MEFs with multiple alphaviruses failed to elicit detectable IFN-α/β. In more detailed studies, Sindbis virus (SINV) infection caused dimerization and nuclear migration of IRF3, but minimal IFN-β promoter activity, although surprisingly, the infected cells were competent for IFN production by other stimuli early after infection. A SINV mutant defective in host macromolecular synthesis shutoff induced IFN-α/β in the MEF cultures dependent upon the activities of the TBK1 IRF3 activating kinase and host pattern recognition receptors (PRRs) PKR and MDA5 but not RIG-I. These results suggest that wild-type alphaviruses antagonize IFN induction after IRF3 activation but also may avoid detection by host PRRs early after infection.     

Expression of Mycobacterium tuberculosis MPT64 in recombinant Myco. smegmatis: purification, immunogenicity and application to skin tests for tuberculosis

Proteins secreted across the cell wall of mycobacteria are important antigens recognized early in the host response to mycobacterial infection. MPT64 is a 23-kD secreted protein restricted to members of the Mycobacterium tuberculosis complex which elicits T cell responses and cutaneous DTH reactions in Myco. tuberculosis-infected animals. Patients with tuberculosis and their tuberculin-positive contacts respond to the protein, but recipients of bacille Calmette–Guérin (BCG) vaccine strains lacking the mpt64 gene do not. In the present study, we describe the development of a unique recombinant mycobacterial vector which secretes the encoded Myco. tuberculosis protein MPT64 at high levels into the culture filtrate, from which the protein is isolated by a single-step affinity chromatographic step. The purified protein was recognized by both polyclonal and monoclonal anti-MPT64 antibodies. The T cell reactivity of the protein was confirmed by its ability to stimulate human anti-rMPB64 T cell lines. The Myco. smegmatis recombinant MPT64 protein was superior to the Escherichia coli rMPB64 protein, which has identical amino acid sequence, in eliciting cutaneous DTH reactions in guinea pigs sensitized with Myco. tuberculosis. Animals sensitized with BCG strains lacking the mpb64 gene failed to respond to MPT64. Similarly, interferon-gamma (IFN-γ) responses in tuberculosis patients and their contacts were higher to the Myco. smegmatis form of the protein. The potential of this form of the Myco. tuberculosis MPT64 protein as a skin test reagent for tuberculosis is discussed.     

重组人干扰素α-2b喷雾剂人群试验的安全性评价

目的评价重组人干扰素α2b喷雾剂(远策素喷雾剂)人群应用预防SARS等呼吸道病毒感染的安全性。方法采用随机、同期平行对照的现场流行病学实验方法进行评价,用药5d,随访10d。结果用药期间,与对照组比较,用药组体温未见异常;用药期间用药组出现的不良反应有头痛(4.83%～7.09%)、头晕(7.17%～11.63%)、乏力(8.55%～15.06%)、肌肉酸痛(4.43%～7.09%)、咽干(12.10%～17.85%)、咽痛(6.25%～8.72%)、腹痛(2.30%～5.50%)、腹泻(2.45%～5.66%)等,不良反应的发生率均高于对照组(P<0.05);不良反应主要出现在用药的前3天;除咽干和乏力外,其他症状在停药后显著下降,其发生率甚至显著低于对照组;用药期间鼻塞、咳嗽和咯痰发生率两组差异无统计学意义;对照组的皮疹发生率显著高于用药组。在整个用药过程中未发现国外志愿者试验发生的血涕现象。结论应用远策素喷雾剂可引起一些较轻的流感样不良反应,但所有症状均为可逆性反应,停药后可消失;未见有其他严重不良反应的发生,在人群中应用是安全的。     

Interferon response heterogeneity: activation of a pro-inflammatory response by interferon alpha and beta. A possible basis for diverse responses to interferon beta in MS

Interferon gamma (IFN-gamma) stimulates the (pro-inflammatory) type II interferon receptor and is known to exacerbate multiple sclerosis (MS). In contrast, IFN-alpha and IFN-beta are ligands for the (anti-inflammatory) type I interferon receptor and are beneficial in some (but not all) patients with MS. Should IFN-beta elicit a type-II-like pro-inflammatory response, the beneficial effects might be attenuated. These studies were undertaken to test this possibility with the use of quinolinic acid (QUIN) formation as a measure of type II receptor activation. In normal human macrophage cultures, IFN-gamma was the most potent stimulus for QUIN formation. Generally, IFN-beta and IFN-alpha were less potent. However, an unexpected inter-patient variability was observed. In some subjects, IFN-alpha was more potent than IFN-beta. In other subjects, IFN-beta was more potent than IFN-alpha. The present data demonstrate an inter-subject variability for QUIN production following exposure to the interferons. MS patients who demonstrate a pro-inflammatory response to IFN-beta (e.g., increased QUIN) may be less likely to benefit from this therapy.     

重组乙型肝炎病毒变异s基因的表达及其抗原性的分析

目的 构建乙型肝炎病毒（HBV）变异s基因真核表达载体。研究变异所致乙肝表面抗原（HBsAg)免疫学性状的改变。方法 利用Dra Ⅲ和XhoI双酶切含有突变位点的HBV DNA 1．2拷贝的质粒P．38Ⅱ，获得904bp带有突变点的HBV－S基因片段。将其置换含有HBV DNA（adr亚型）S和S2片段的真核表达载体pCMV-S2．S的相应片估，从而构建s基因nt587G→A突变的真核表达载体CMV-S2.S 145R；并转染人肝癌细胞系Hep G2，以获得分泌变异型HBsAg的细胞系。利用EIA及细胞免疫染色法，探讨变异抗原与抗－HBs结合力的变化。结果 构建了HBsAg的第145位甘氨酸－精氨酸突变体的真核表达载体。将其转染哺乳动物细胞后第3天，培养上清中用EIA检测用HBsAg呈阳性，A值随时间延长而上升，但变异型的A值明显低于野生型。变异型和野生型HBsAg细胞免疫化学检测均有部分细胞呈阳性，但差异不显著。结论 HBsAg第145位甘氨酸－精氨酸的突变体的真核表达载体产物具有良好的抗原性，能够与抗－HBs结合，但与野生型相比结合力明显降低。     

The nucleocapsid protein of measles virus blocks host interferon response

Measles virus (MV) belongs to the genus Morbillivirus of the family Paramyxoviridae. A number of paramyxoviruses inhibit host interferon (IFN) signaling pathways in host immune systems by various mechanisms. Inhibition mechanisms have been described for many paramyxoviruses. Although there are inconsistencies among previous reports concerning MV, it appears that P/V/C proteins interfere with the pathways. In this study, we confirmed the effects of MV P gene products of a wild MV strain on IFN pathways and examined that of other viral proteins on it. Interestingly, we found that N protein acts as an IFN-α/β and γ-antagonist as strong as P gene products. We further investigated the mechanisms of MV-N inhibition, and revealed that MV-N blocks the nuclear import of activated STAT without preventing STAT and Jak activation or STAT degradation, and that the nuclear translocation of MV-N is important for the inhibition. The inhibitory effect of the N protein was observed as a common feature of other morbilliviruses. The results presented in this report suggest that N protein of MV as well as P/V/C proteins is involved in the inhibition of host IFN signaling pathways.     

Kaposi's sarcoma in AIDS patients: Long-term treatment with recombinant interferon alpha-2A and chemotherapy

Summary We evaluated the response to therapy and outcome in patients with HIV-associated KS. Eighteen of 26 patients with newly diagnosed KS were treated continuously with IFN until progression of the disease occurred. In most patients with progressive disease, chemotherapy, usually with vinca alcaloid derivatives was instituted. Results were disappointing: 10 of 26 patients (38.5%) died after a median follow-up period of 4.5 months. Survival was shortest in patients who developed opportunistic infections, malignant lymphoma, or had a low OKT₄/OKT₈ ratio. Only one patient showed a complete remission and one patient had a partial remission under IFN therapy. Five additional patients had stable disease. Chemotherapy was without measurable effect on KS in patients who had progressive disease under IFN. IFN therapy was associated with various, not life-threatening adverse effects and was best tolerated by patients with a low OKT₄/OKT₈ ratio. Our results indicate that only a small portion of AIDS patients with KS seem to benefit from a continuous treatment with IFN.Abbreviations AIDS Acquired immunodeficiency syndrome - CNS Central nervous system - ELISA Enzyme linked immunosorbent assay - ESR Erythrocyte sedimentation rate - HIV Human immunodeficiency virus - IFN Recombinant interferon alpha-2a - KS Kaposi's sarcoma - WHO World Health Organization     

干扰素调节因子3 rs2304204野生型及突变型重组质粒的构建及活性分析

目的构建干扰素调节因子3（IRF-3）rs2304204野生型及突变型重组质粒并比较二者启动子活性。为进一步研究IRF-3对HBV感染的影响打下基础。方法以人全血DNA为模板,扩增含rs2304204位点的IRF-3启动子区1355bp目的序列,插入pGL3-Basic载体中,构建rs2304204野生型的重组质粒（wIRF-3）。以wIRF-3为模板,利用基因定点突变试剂盒构建rs2304204突变型重组质粒（mIRF-3）。wIRF．3、mIRF-3和pGL3-Basic质粒分别转染HEK293细胞,采用双荧光素酶报告基因检测试剂盒检测荧光素酶活性,并计算荧光素酶相对活性单位（RLU）。结果成功构建IRF-3rs2304204野生型及突变型重组质粒,且wIRF-3质粒转染组RLU明显高于mIRF-3质粒转染组（P〈0．005）。结论野生型重组质粒的启动子活性明显高于突变型重组质粒,启动子活性的不同可能进而影响机体抗HBV感染的临床结局。     

异柠檬酸脱氢酶1与突变体重组慢病毒的制备及表达

目的:制备异柠檬酸脱氢酶1野生型(IDH1)和R132H突变型(mut IDH1)基因重组慢病毒,感染人胶质瘤来源的细胞系U87细胞并观察目的基因的表达。方法:利用基因克隆技术构建IDH1和mut IDH1基因重组慢病毒载体p LVX-IDH1-mCMV-ZsGreen-PGK-Puro和p LVX-mutIDH1-mCMV-ZsGreen-PGK-Puro,转染293T细胞,进行慢病毒包装,获得慢病毒颗粒;慢病毒颗粒感染HEK293细胞,采用逐孔稀释滴度测定法测慢病毒滴度;IDH1和mut IDH1基因重组慢病毒感染U87细胞,观察感染效率,Western Blot检测IDH1和mut IDH1基因在U87细胞的表达。结果:成功制备IDH1和mut IDH1基因重组慢病毒颗粒,病毒滴度均为1.0×108TU/ml;感染U87细胞,Western Blot结果显示:IDH1组中IDH1蛋白水平高于mut IDH1组和空载体对照组; mut IDH1组中mut IDH1蛋白条带清晰,表达量高,IDH1组和对照组均不表达mut IDH1蛋白。结论:成功制备IDH1和mut IDH1基因重组...     

Effects of recombinant leukocyte interferon on serum immunoglobulin concentrations and lymphocyte subpopulations in chronic hepatitis B

To investigate immune effects of interferon (IFN) therapy in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B, serum immunoglobulin concentrations and peripheral lymphocyte subpopulations were sequentially studied before, during, and after therapy in nine patients who were treated with recombinant human -IFN in doses ranging from 3 to 10 million units per day for 28 days. Serum immunoglobulin A levels decreased significantly, from 414±23 mg/dl (mean ± SE) to 379±28 mg/dl (P<0.05), after the first week of therapy and to a bottom value of 323±20 mg/dl (P<0.001) at the fourth week. Immunoglobulin G levels decreased significantly, from 2603±175 to 2328±169 mg/dl (P<0.005), after the first week of therapy and to a bottom value of 2005±199 mg/dl (P<0.001) at the fourth week. Immunoglobulin M levels were also reduced significantly after 3 weeks of therapy (from 229±23 to 188±15 mg/dl;P<0.01). These reductions in immunoglobulins A, G, and M returned to pretreatment levels by 4 months after the end of the therapy. In lymphocyte subpopulations, significant depressions were found in CD3-, CD4-, CD8-, and B1-positive cells in peripheral blood after the first week of therapy (CD3, from 1700±114 to 1234±114/mm³,P<0.005; CD4, from 1036±88 to 780±64/mm³,P<0.005; CD8, from 620±57 to 426±60/mm³,P<0.05; and B1, from 519±84 to 276±48/mm³,P<0.01) followed during therapy, while Leul la-positive cells did not change significantly. During the 6-month follow-up period, three patients had a sustained clinical remission in which HBeAg disappeared from serum. Disappearance of HBeAg was unassociated with initial levels or percentage changes of serum immunoglobulins and peripheral lymphocytes expressing each of the test markers in these patients. These findings suggest that immune effects of IFN therapy are independent from its antiviral effects.     

The C protein of measles virus inhibits the type I interferon response

Type I interferons (IFNalpha/beta) are an important part of innate immunity to viral infections because they induce an antiviral response and limit viral replication until the adaptive response clears the infection. Since the nonstructural proteins of several paramyxoviruses inhibit the IFNalpha/beta response, we chose to explore the role of the C protein of measles virus (MV) in such inhibition. Previous studies have suggested that the MV C protein may serve as a virulence factor, but its role in the pathogenesis of MV remains undefined. In the present study, a recombinant MV strain that does not express the C protein (MV C-) and its parental strain (Ed Tag) were used. Growth of MV C- was restricted in human peripheral blood mononuclear cells and HeLa cells, but in the presence of neutralizing antibodies to IFNalpha/beta, MV C- produced titers that were equivalent to those of Ed Tag. In addition, expression of the MV C protein from plasmid DNA inhibited the production of an IFNalpha/beta responsive reporter gene and, to a lesser extent, inhibited an IFNgamma responsive reporter gene. The ability of the MV C protein to suppress the IFNalpha/beta response was confirmed using a biologic assay. After IFNbeta stimulation, HeLa cells infected with Ed Tag produced five-fold less IFNalpha/beta than cells infected with MV C-. While the mechanism of inhibition remains unclear, these data suggest that the MV C protein plays an important role in the pathogenesis of MV by inhibiting IFNalpha/beta signaling.     

慢性丙型肝炎肝组织HCV特异性CTL活性对干扰素应答效果的影响

目的 了解肝组织丙型肝炎病毒（HCV）特异性细胞毒性T淋巴细胞（CTL）活性对慢性丙型肝炎患者干扰素治疗效果的影响。方法 用标准铬释放法对45例拟接受α干扰素治疗的慢性丙型肝炎（慢丙肝）患者肝组织CD8^ HCV特异性细胞毒性T淋巴细胞（HCV－CTL）活性进行检测,观察CTL活性与干扰素疗效的关系。结果 45例慢丙肝中20例（44．4％）肝组织HCV－CTL活性阳性。在完成干扰素治疗的42例中,19例HCV－CTL活性阳性。经过6个月的干扰素治疗,42例中共18例（42．9％）获得治疗终点完全应答15例（78．9％）为ETR,而23例HCV－CTL活性阴性患者仅3例（13．05）为ETR（P＜0．01）;10例持续应答者均为HCV－CTL活性阳性患者。结论 机体细胞免疫,尤其是CD8^ HCV-CTL介导的细胞免疫在决定慢性丙型肝炎干扰素治疗的效果中起重要作用。     

Augmentation of endotoxin fever by recombinant human beta interferon in rabbits.

Nonpyrogenic amounts of endotoxin (0.1 to 1 ng/kg), hardly detectable by conventional Limulus amoebocyte lysate tests, could produce a fever of around 1 degree C when injected with a nonpyrogenic dose (6 X 10(5) U/kg) of recombinant human beta interferon (IFN-beta) in rabbits. Release of endogenous IFN and tumor necrosis factor by endotoxin was also dramatically increased by recombinant human IFN-beta, and their levels in the blood were closely correlated with the increase of body temperature. These data suggest, if the synergism between IFN and endotoxin also operates in the homologous system (human IFN-human cells), that contaminating endotoxin in IFNs, even if not detectable by Limulus amoebocyte lysate test, can contribute to IFN fever to a considerable extent in humans.     

Kinetics of antibody response to hepatitis B virus determinants and to recombinant vaccines in Italy.

The kinetics of antibody response to the group determinant a and subdeterminants d and y of hepatitis B virus were studied after infection and following immunisation with two recombinant DNA yeast-derived hepatitis B vaccines. The initial antibody response was to the subdeterminant epitopes, whereas anti-a antibody, which provides protection against different subtypes of the virus, was not detected for some weeks or months. The delay in the development of anti-a antibody after active immunisation raises important issues of early protection against infection.     

重组人干扰素α-2b喷雾剂预防SARS等呼吸道病毒感染的人群试验研究

目的评估重组人干扰素α2b喷雾剂(远策素喷雾剂)预防SARS等常见呼吸道病毒感染的效果。方法研究对象共14391人,用药剂量为90万IU/次,每日2次,连用5d,未次用药后15d取血,或用药前和用药3周后采取双份血清。采用随机、对照方法检测血清抗SARSCoVIgG抗体;采用双盲、随机、安慰剂对照方法测定血清抗常见呼吸道病毒(B型流感病毒、副流感病毒1～3型,呼吸道合胞病毒及腺病毒3、7型)的血清IgM抗体。结果两次实验中,干扰素组血清SARS病毒IgG抗体阳性率均较试验组高,但差异无统计学意义(P>0.05)。但用药组应用干扰素后副流感病毒1～3型,B型流感病毒,腺病毒3、7型和呼吸道合胞病毒IgM抗体阳性率(依次为6.45%、4.52%、4.30%和17.20%)均低于对照组(依次为19.40%、13.60%、7.12%和25.62%)。其中副流感病毒、B型流感病毒、腺病毒3种病毒IgM抗体阳性率差异均有统计学意义(P<0.01)。结论应用远策素喷雾剂鼻和咽部喷雾能不同程度地降低用药人群常见呼吸道病毒的感染率。