Diagnosis of Epstein-Barr virus infection in clinical serum samples by an SPR biosensor assay.

Label-free affinity biosensors offer a promising platform for the development of a new generation of medical diagnostic technologies. Nevertheless, when such sensors are used in complex biological media, adsorption of non-targeted medium components prevents the specific detection of the analyte. In this work, we introduce for the first time a biosensor assay based on surface plasmon resonance (SPR) capable of diagnosing different stages of Epstein-Barr virus (EBV) infections in clinical serum samples. This was achieved by simultaneous detection of the antibodies against three different antigens present in the virus. To prevent the interference of the fouling from serum during the measurement, the SPR chips were coated by an antifouling layer of a polymer brush of poly[oligo(ethylene glycol) methacrylate] grown by surface-initiated atom transfer radical polymerization. The bioreceptors were then attached via hybridization of complementary oligonucleotides. This allowed the sensor surface to be regenerated after measurement by disrupting the complementary pairs above the oligonucleotides' melting temperature and attaching new bioreceptors. In this way, the same sensing surface could be used repeatedly. The procedure used in this work will serve as a prototype strategy for the development of label-free affinity biosensors for diagnostics in blood serum or plasma samples. This is the first example of detection of marker of a disease in clinical serum samples by an optical affinity biosensor.

Influence of immunization with non-genotoxic PAH-KLH conjugates on the resistance of organisms exposed to benzo(a)pyrene.

Polycyclic aromatic hydrocarbons (PAH) are recognized as common environmental pollutants released into the environment from many natural as well as man-made sources, and some have been classified as potent carcinogens. The main representative of the carcinogenic PAH is benzo(a)pyrene (B(a)P) which is known to induce genotoxic effects in vitro and in vivo, detected as PAH-DNA adducts. Long-term PAH exposure may be accompanied by an immunological response with the formation of antibodies against PAH as well as against PAH-DNA adducts. This paper describes the use of four PAH-keyhole-limpet haemocyanin (KLH) conjugates for the induction of specific and cross-reactive anti-PAH antibodies and focuses on the potential protective effects of anti-PAH antibodies produced after immunization of mice. In the in vitro experiments with HepG-2 cells, the genotoxicity of the PAH-KLH conjugates and the neutralizing effect of induced anti-PAH antibodies were evaluated. The titer of specific anti-PAH antibodies in sera and the amounts of DNA adducts in liver homogenates from immunized mice were investigated in vivo. The results show that anti-PAH antibodies of class IgG were induced during immunization. All the PAH-KLH conjugates tested were non-genotoxic and did not induce detectable DNA adducts in HepG2 cells or in the liver of immunized mice. The results show that only B(a)P-specific and B(a)P cross-reactive antibodies are able to neutralize B(a)P or its activated metabolites, which was revealed by a sudden decrease in the titer of anti-B(a)P antibodies in mouse sera after exposure to B(a)P. Furthermore, the anti-B(a)P antibodies produced by immunization were effective in reducing the amount of DNA adducts in mouse livers after intraperitoneal (i.p.) exposure to B(a)P. The results suggest that immunization with PAH-KLH conjugates can protect organisms against the adverse effects of carcinogenic PAH.

The Bloodgen Project of the European Union, 2003-2009.

The Bloodgen project was funded by the European Commission between 2003 and 2006, and involved academic blood centres, universities, and Progenika Biopharma S.A., a commercial supplier of genotyping platforms that incorporate glass arrays. The project has led to the development of a commercially available product, BLOODchip, that can be used to comprehensively genotype an individual for all clinically significant blood groups. The intention of making this system available is that blood services and perhaps even hospital blood banks would be able to obtain extended information concerning the blood group of routine blood donors and vulnerable patient groups. This may be of significant use in the current management of multi-transfused patients who become alloimmunised due to incomplete matching of blood groups. In the future it can be envisaged that better matching of donor-patient blood could be achieved by comprehensive genotyping of every blood donor, especially regular ones. This situation could even be extended to genotyping every individual at birth, which may prove to have significant long-term health economic benefits as it may be coupled with detection of inborn errors of metabolism.

Live cell vaccines expressing B7.1, monocyte chemoattractant protein 1 and granulocyte-macrophage colony stimulation factor derived from mouse HPV16-transformed cells.

One of the gene therapy strategies in oncology is immunization with cancer cells that express various cytokines. We used a thymidine-kinase deficient (cTK-) cell line designated 123IA, which had been derived from HPV16-transformed mouse (C57BL/6) cells MK16/I/III/ABC (MK16). To obtain genetically modified cells, 123IA cells were transfected with bicistronic plasmid vectors carrying the herpes simplex type 1 thymidine kinase (HSV TK) gene and either the gene for the mouse B7.1 (CD80) co-stimulatory molecule or the gene for the monocyte-chemoattractant protein 1 (MCP-1). For control purposes, a plasmid vector carrying only the HSV TK gene was used. The transfected cells were cultivated in medium supplemented with hypoxanthine, aminopterin and thymidine. For comparative purposes we also used B9 cells, which express the granulocyte-macrophage colony stimulation factor (GM-CSF) and had been derived from 123A cells by transduction with the recombinant adeno-associated virus carrying the HSV TK gene and the mouse GM-CSF gene. All of the cell lines isolated were found to be sensitive to minute amounts of ganciclovir, revealing the production of HSV TK, and to express the respective transgenes. When inoculated into 5-week-old female syngeneic mice, cells expressing either GM-CSF or B7.1 were non-oncogenic. On the other hand, nearly all mice inoculated with MCP-1-producing cells developed tumours, though considerably later than animals inoculated with the same dose of the parental MK16 cells. Animals injected with GM-CSF- or B7.1-producing cells were protected against challenge with the parental MK16 cells. When another mouse (C57BL/6) HPV16-transformed oncogenic cell line, TC-1, which differs from the MK16 cells in a number of properties such as MHC class I and B7.1 expression, was used for the challenge, the protective effect was much less pronounced.

Surface plasmon resonance biosensor for direct detection of antibody against Epstein-Barr virus.

This paper describes the direct label-free detection of antibodies against the Epstein-Barr virus (anti-EBNA) using a surface plasmon resonance (SPR) biosensor. The antibody detection was performed using the immunoreaction between anti-EBNA and a respective synthetic peptide (EBNA-1), which was conjugated with bovine serum albumin (BSA-EBNA) and immobilized on the sensor surface. Three immobilization chemistries for the attachment of BSA-EBNA were investigated to optimize ligand density and minimize loss of EBNA-1 immunoreactivity. The developed SPR biosensor functionalized with the optimal immobilization method was calibrated and characterized in terms of detection limit, reproducibility, regenerability and storability. It was demonstrated that the sensor is capable of detecting concentrations of anti-EBNA as low as 0.2 ng/ml (approximately 1 pM) both in buffer and 1% human serum and can be stored and regenerated for repeated use.

Combined immunization with DNA and transduced tumor cells expressing mouse GM-CSF or IL-2.

A combination of different types of vaccines usually induces enhanced immune responses in comparison to immunization with single vaccines. The highest efficacy of a heterologous prime-boost strategy is mostly achieved after priming with a DNA vaccine and boosting with a recombinant virus or a protein vaccine. The aim of this study was to determine whether the combination of a DNA and cellular vaccine elicits stronger antitumor immune responses than vaccines used alone and to find out whether the efficacy of this combined immunization depends on the sequence in which the vaccines were applied. We utilized experimental vaccines that proved to be partially effective in protection against mouse tumor cells representing models of human papillomavirus-induced malignancies. The fusion gene Sig/E7GGG/LAMP-1, inoculated via a gene gun, was used for DNA immunization. As cellular vaccines, HPV16 E6/E7 and H-ras transformed B9 or 181 cells transduced with the gene coding for GM-CSF or IL-2, respectively, were applied. In both preventive and therapeutic immunizations, inoculation first with the DNA vaccine followed by application of a cellular vaccine induced the best protection from tumor growth. These results were confirmed by detection of immune reactions with in vitro tests. We failed to enhance immune reactions by utilization of an equivalent mix of B9 and 181 cells, but the addition of the second DNA-vaccine dose applied simultaneously with a cellular-vaccine boost moderately increased antitumor response. Our findings suggest the benefit of the heterologous prime-boost strategy based on combination of a DNA vaccine with a cellular vaccine and importance of sequence in which the vaccines are administered.

Treatment of minimal residual disease after surgery or chemotherapy in mice carrying HPV16-associated tumours: Cytokine and gene therapy with IL-2 and GM-CSF.

Moderately immunogenic HPV16-associated tumours TC-1 (MHC class I+, HPV16 E6/E7+, G12V Ha-ras+) and MK16/1/IIIABC (MK16, MHC class I-, HPV16 E6/E7+, G12V Ha-ras+), both of the H-2b haplotype and transplanted in syngeneic mice, were used to examine the effects of local IL-2 and GM-CSF cytokine or gene therapy in the treatment of minimal residual tumour disease. The mice carrying MHC class I+ TC-1 tumour residua after surgery were injected into the site of the surgery either with irradiated, IL-2 gene-modified MK16 tumour cells, or with recombinant IL-2. It has been found that both, the recombinant IL-2 and the IL-2 gene-modified tumour vaccine substantially reduced the percentage of tumour recurrences in the operated mice. Similarly, when the mice carrying TC-1 tumour residua after surgery were injected with recombinant GM-CSF, the recombinant GM-CSF inhibited growth of the tumour residua in the operated mice. Gene therapy with irradiated, GM-CSF secreting MK16 cells did not produce any tumour-inhibitory effect. In further experiments, mice bearing s.c. TC-1 tumours were injected i.p. with ifosfamide derivative CBM-4A and 8 days later, peritumourally, either with IL-2 gene-modified and IL-2-producing MK16 cells, or with recombinant IL-2. It has been found that both, the recombinant IL-2 and the IL-2 gene therapy substantially reduced the percentage of tumour-bearing mice. When the mice bearing s.c. TC-1 tumours were injected i.p. with ifosfamide derivative CBM-4A and then, peritumourally, either with irradiated, GM-CSF gene-modified and GM-CSF-producing MK16 cells, or with recombinant GM-CSF, it was found that both, the recombinant GM-CSF and GM-CSF gene therapy inhibited growth of tumour residua. Comparative experiments were performed with the MHC class I-, metastasizing tumour MK16. It has been found that both, recombinant IL-2 and GM-CSF, can inhibit growth of the tumour residua after surgery or chemotherapy. The lung metastases in mice with surgical minimal residual tumour disease or in mice with tumour residua after chemotherapy were inhibited by IL-2 but not by GM-CSF. The MK16 tumour vaccine producing IL-2 inhibited growth of tumour residua after chemotherapy, but not the tumour residua after surgery. The GM-CSF-producing vaccine was without significant effect in both, surgically- and chemotherapeutically-induced minimal residual MK16 tumour disease. In conclusion, the MHC class I+ and MHC class I-, HPV16-associated tumours were found to be sensitive to IL-2 and GM-CSF therapy after surgery or after cytoreductive chemotherapy. It is yet to be addressed if this is more general case with HPV16-associated experimental tumours. If so, it would be of interest to further investigate whether such adjuvant therapy can also help to eradicate the residua after surgery and chemotherapy in patients carrying HPV16-associated neoplasms.

Delivery of recombinant adeno-associated virus by jet injection.

The jet-injection technology was used for delivery of recombinant adeno-associated virus (rAAV). Although AAV-based vectors are an attractive tool in gene therapy, some methodological and technical problems of their targeted delivery remain to be solved. We tried to address some of these cell-targeting problems by using a new low-volume needleless injection device the Swiss Injector. First we tested, by electron microscopy, whether jet-injection would have any detrimental effect on rAAV particle integrity. Second, we compared transgene expression after infection of 293T cells with fired or control (non-fired) rAAV that expressed the green fluorescent protein (GFP), beta-galactosidase (beta-gal), the B7.1 molecule, and interleukin 2 (IL2). Third, an rAAV carrying the genes coding for beta-gal was jet-injected into mouse subcutaneous (s.c.) tumours. The staining of tumour cryosections revealed beta-gal expression 72 h after the delivery. Our study demonstrated the applicability of the Swiss Injector for the delivery of rAAV into tumour tissue without either vector particle integrity or the level of expression of the transgenes, as tested in vitro, being affected. The jet-injection technology could improve the distribution of vector particles in the tumour mass without leakage of liquid from the injection site.

Immunization with live HPV-16-transformed mouse cells expressing the herpes simplex thymidine kinase and either GM-CSF or IL-2.

From mouse (C57BL/6) HPV-16 transformed cells denoted MK16/1/IIIABC (MK16) a cellular thymidine kinase deficient (cTK-) cell line was isolated. These cTK- cells were transduced by bicistronic recombinant adeno-associated viruses (rAAV) carrying the herpes simplex virus thymidine kinase gene and the gene for either the mouse granulocyte-macrophage colony stimulating factor (GM-CSF) or mouse interleukin-2 (IL-2). Transduced cells were highly sensitive to minute amounts of ganciclovir (GCV) and synthesized moderate amounts of the respective cytokines. A number of cell clones were tested for the cytokine production. The two best producer cell lines, the GM-CSF-producing cells denoted B9 and the IL-2-producing cells denoted 181, were selected for further experiments. Neither B9 nor 181 cells were tumorigenic in syngeneic animals. As inducers of antitumour immunity against challenge with MK16 cells, B9 cells proved superior to the 181 cells. GCV treatment did not markedly influence the level of immunity induced.

Chemoimmunotherapy in mice carrying HPV16-associated, MHC class I+ and class I- tumours: Effects of CBM-4A potentiated with IL-2, IL-12, GM-CSF and genetically modified tumour vaccines.

The effectiveness of chemoimmunotherapy with ifosfamide derivative CBM-4A and recombinant IL-2, IL-12, GM-CSF, or genetically modified, cytokine-producing tumour vaccines was examined in mice carrying HPV16-associated, MHC class I+ (TC-1), and MHC class I- (MK16) tumours. Intraperitoneal treatment of TC-1 or MK16 tumour-bearing mice with CBM-4A produced a significant tumour-inhibitory effect. When the i.p. treatment of the MHC class I+ TC-1 tumour-bearing mice with CBM-4A was followed by peritumoral s.c. administration of IL-2, IL-12, or both cytokines, the growth of TC1 tumours was inhibited more vigorously than after the chemotherapy alone. In contrast, when the i.p. treatment ofEthe MHC class I- MK16 tumour-bearing mice with CBM-4A was followed by peritumoral s.c. administration of IL-2 or IL-12, the cytokine therapy had no potentiating effect. The only potentiating effect of the MK16 tumour immunotherapy was obtained when the i.p. CBM-4A pretreatment was followed by peritumoral s.c. administration of IL-2 plus IL-12. InEfurther experiments, the TC-1 and MK16 tumour-bearing mice were i.p. pretreated with CBM-4A and then injected s.c., peritumorally, with genetically modified, IL-2 or GM-CSF-producing MK16 tumour vaccines. Whereas both genetically modified tumour vaccines produced a substantial tumour-inhibitory effect in mice carrying TC-1 tumours, no effect of the vaccines was observed in mice carrying MK16 tumour inocula. The systemic effects of local cytokine treatment were examined in mice carrying s.c. MK16 neoplasms, which were pretreated i.p. with CBM-4A, and then injected peritumorally with IL-2 or GM-CSF. Peritumoral administration of GM-CSF had no antimetastatic effect, whereas peritumoral IL-2 administration produced substantial reduction of lung metastases. The systemic antimetastatic effect of IL-2 contrasted with the negligible effect of IL-2 on the s.c. MK16 tumour inoculum. Taken collectively, the results indicate that in mice carrying the MK16 (MHC class I-) tumour, the effects of the adjuvant cytokine therapy were substantially weaker than in mice carrying the TC-1 (MHC class I+) tumour inoculum.