Evaluation of parameters for efficient purification and long-term storage of herpes simplex virus-based vectors

Replication competent oncolytic herpes simplex virus (HSV) vectors have been used extensively to treat solid tumors with promising results. However, highly defective HSV vectors will be needed for applications that require sustained therapeutic gene expression in the absence of vector-related toxicity or inflammation. These vectors require complementing cell lines for their manufacture, creating significant challenges to achieve high yields of infectious virus particles. We recently described an improved upstream process for the production of a non-cytotoxic HSV vector for gene therapy applications. Here, we sought to optimize the downstream conditions for purification and long-term storage of the same vector, JΔNI5. We compared different methods to remove cellular impurities and concentrate the vector by monitoring both physical and biological titers, resulting in the establishment of optimal conditions for vector production. To optimize the long-term storage parameters for non-cytotoxic HSV vectors, we evaluated vector stability at low temperature and sensitivity to freeze-thaw cycles. We report that suboptimal purification and storage methods resulted in loss of vector viability. Our results describe effective and reproducible protocols for purification and storage of HSV vectors for pre-clinical studies.

A PCR-amplified transgene fragment flanked by a single copy of a truncated inverted terminal repeat for recombinant adeno-associated virus production prevents unnecessary plasmid DNA packaging

The application of recombinant adeno-associated viruses (rAAVs) for gene therapy faces certain challenges, including genome packaging of non-vector sequences. Inverted terminal repeats (ITRs) flanking the rAAV genome, comprising three inverted repeat regions (A, B, and C) and a non-inverted repeat region (D), contribute to non-vector genome packaging. We aimed to circumvent this issue by comparing the properties of rAAV containing DNA plasmids and PCR-amplified transgenes, including a single copy of the AD sequence (rAAV-pAD/L-AD, respectively), which is a truncated form of ITR, with those of wild-type ITR genome (single-stranded and self-complementary AAV; ssAAV and scAAV). The packaging efficiency of rAAV-pAD/L-AD was found to be comparable to that of scAAV, whereas the transduction efficiency of rAAV-pAD/L-AD was lower than that of ss/scAAV. Remarkably, rAAV-L-AD reduced the plasmid backbone packaging contamination compared to ss/scAAV. Furthermore, to confirm the functionality of this system, we generated a rAAV-L-AD harboring a short hairpin RNA targeting ATP5B (rAAV-L-AD-shATP5B) and found that it caused a significant decrease in ATP5B mRNA levels when transduced into HEK293EB cells, suggesting that it was functional. Thus, our system successfully packaged L-AD into capsids with minimal contamination of plasmid DNA, offering a novel functional packaging platform without causing plasmid backbone encapsidation.

Highly Efficient Ultracentrifugation-free Chromatographic Purification of Recombinant AAV Serotype 9

Recombinant adeno-associated virus serotype 9 (rAAV9) can specifically transduce muscle and neuronal tissues; thus, rAAV9 can potentially be used in gene therapy. However, rAAV9 is the most challenging rAAV serotype to purify. Traditionally, rAAV9 has been purified by ultracentrifugation, which is not scalable. We recently described a chromatographic purification protocol for rAAV1; this protocol can achieve scalable purifications. In this study, we attempted to optimize this protocol for purifying rAAV9 preparations, and we developed a novel, effective method for high-yield purification of rAAV9 using quaternary ammonium anion exchangers and size-exclusion chromatography. The final purified rAAV9 contained mainly three capsid proteins, as observed by SDS-PAGE. Furthermore, negative-stain electron microscopy demonstrated that 96.1% ± 1.1% of rAAV9 particles carried the viral genome containing the EGFP transgene, indicating that impurities and empty capsids can be eliminated with our purification protocol. The final rAAV9 titer obtained by our protocol totaled 2.5 ± 0.4 × 10¹⁵ viral genomes produced from ∼3.2 × 10⁹ HEK293EB cells. We confirmed that our protocol can also be applied to purify other varied AAV genome constructs. Our protocol can scale up production of pure rAAV9, in compliance with current good manufacturing practice, for clinical applications in human gene therapy.

DOK7 gene therapy enhances motor activity and life span in ALS model mice

Amyotrophic lateral sclerosis (ALS) is a progressive, multifactorial motor neurodegenerative disease with severe muscle atrophy. The glutamate release inhibitor riluzole is the only medication approved by the FDA, and prolongs patient life span by a few months, testifying to a strong need for new treatment strategies. In ALS, motor neuron degeneration first becomes evident at the motor nerve terminals in neuromuscular junctions (NMJs), the cholinergic synapse between motor neuron and skeletal muscle; degeneration then progresses proximally, implicating the NMJ as a therapeutic target. We previously demonstrated that activation of muscle‐specific kinase MuSK by the cytoplasmic protein Dok‐7 is essential for NMJ formation, and forced expression of Dok‐7 in muscle activates MuSK and enlarges NMJs. Here, we show that therapeutic administration of an adeno‐associated virus vector encoding the human DOK7 gene suppressed motor nerve terminal degeneration at NMJs together with muscle atrophy in the SOD1‐G93A ALS mouse model. Ultimately, we show that DOK7 gene therapy enhanced motor activity and life span in ALS model mice.

Removal of small non-enveloped viruses by nanofiltration

BACKGROUND AND OBJECTIVES

Nanofiltration is one of the most effective virus reduction methods in the manufacturing process of plasma products. However, it is difficult to remove small viruses from high molecular weight protein preparations like immunoglobulin G or factor VIII complex by nanofiltration, because the size of the protein is similar to that of viruses. In order to separate the viruses from these proteins by nanofiltration, it is necessary to change the size of either one. In this study, we report that such non-enveloped viruses as human parvovirus B19 (B19), human encephalomyocarditis virus (EMC) or porcine parvovirus (PPV) aggregate in the presence of certain kinds of amino acids and could be easily removed by nanofiltration.

MATERIALS AND METHODS

0.3 M Glycine (or other amino acid) solution spiked with viruses was subjected to dead-end single filtration with a 35-nm pore-size filter. Virus removal by nanofiltration was either evaluated by PCR or by infectivity assay.

RESULTS

B19 in a 0.3 M glycine solution was reduced to 1:10(7.5) (7.5-log) by nanofiltration with a 35-nm pore-sized filter, whereas in PBS it was not reduced. Similarly, B19 was also reduced when suspended in other amino acids solutions. This effect was also confirmed with the other small non-enveloped viruses EMC or PPV. When 5% globulin or 5% albumin was added to a 0.3 M glycine solution, the removal rate was decreased.

CONCLUSIONS

These data suggest that viruses in the presence of certain kinds of amino acids could be aggregated and effectively removed by a filter that has a pore size larger than the size of the viruses.

Status of NAT screening for HCV, HIV and HBV: experience in Japan

The first nationwide nucleic acid amplification testing (NAT) for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus type 1 (HIV-1) of voluntarily donated blood after serological pre-screening and before release of cellular components and plasma for fractionation was implemented by the Japanese Red Cross Blood Transfusion Services. The NAT screening assay using multiplex reagent is time-saving, cost effective, and labour-saving procedure for all blood and blood products including short-shelf life platelets. During the 50-mini-pool NAT screening of serologically negative donations (February 1, 2001-April 30, 2001), we were able to screen out 112 HBV-positive, 25 HCV-positive, and 4 HIV-1 positive units from blood and blood components.

The first large-scale nucleic acid amplification testing (NAT) of donated blood using multiplex reagent for simultaneous detection of HBV, HCV, and HIV-1 and significance of NAT for HBV

The first nationwide nucleic acid amplification testing (NAT) for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus type 1 (HIV-1) of voluntarily donated blood after serological pre-screening and before release of cellular components and plasma for fractionation was implemented by the Japanese Red Cross Blood Transfusion Services. From February 1, 2000 to April 30, 2001, specimens from 6,805,010 units of serologically negative donation were screened in minipools of 50 samples within 24 hr after blood donation by NAT using multiplex HBV/HCV/HIV-1 reagent for blood transfusion including short shelf-life platelets. Among them, 112 HBV DNA-positives, 25 HCV RNA positives and 4 HIV-1 RNA positives were screened out and we could prevent transfusion of these NAT positive units. Subtypes/genotypes of HBV DNA, adr/C, adw/A, adw/B, adw/C, ayr/C and ayw/D were found and adr/C was predominant. A total of 61.6 % of them (69/112) were negative by overnight EIA. Sixth three of HBV NAT-positive samples carried virus loads less than 10(4) copies/mL and 92.1 % of them (58/63) were negative by overnight EIA. The virus growth curves of HBV in 6 cases obtained by retrospective and prospective follow-up study showed exponential straight lines in the early stage of serological window periods and the log times of HBV growth (10 fold increase) in serological window period were between 4.6 and 7.6 days. NAT screening with highly sensitive reagents in pool of specimens is useful to exclude blood units with low level of HBV and HBV mutants from blood transfusion.

Prophylaxis of experimental HTLV-I infection in cynomolgus monkeys by passive immunization

The protective effect of purified human immunoglobulin against human T-cell leukaemia virus type I (HTLV-I), designated ATLIG on HTLV-I infection was examined in cynomolgus monkeys (Macaca fascicularis) as a preclinical study. Passive immunization of ATLIG 24 h before challenging HTLV-I protected the monkeys from HTLV-I infection. The result suggests that passive immunization of ATLIG could provide safe and sufficient protection against HTLV-I infection in humans.

[One-stage resected case of dumbbell type tumor of the posterior mediastinum]

We reported a dumbbell type tumor of the posterior mediastinum. The patient was an asymptomatic 40-year-old male. An abnormal shadow in the right lower lung field was pointed out in a mass survey. We recognized a dumbbell type tumor in the posterior mediastinum by chest CT and MRI. The tumor invaded the intervertebral canal through the spinal foramen. It was most clearly seen by MRI myelography. Operation was performed with the patient in a prone position and with an L-shaped skin incision of the back and 11th intracostal thoracotomy and Th11 laminectomy. The dumbbell type tumor was completely removed by this operation. The pathological diagnosis was Schwannoma. The post operative course was good. The one-stage operation is useful for dumbbell type tumors of the posterior mediastinum.

Physicochemical and biological properties of poly(ethylene glycol)-coupled immunoglobulin G. Part II. Effect of molecular weight of poly(ethylene glycol)

In order to obtain a stable human immunoglobulin G (IgG) preparation for clinical use, the chemical coupling of different molecular weights of poly(ethylene glycol)s (PEGs) to IgG molecules was achieved. The abilities of PEG-coupled IgGs (PEG-IgG hybrids) to aggregate were examined when they were subjected to such physicochemical treatments as interfacial exposure, heating, lyophilization, and acid treatment. It was found that the higher the molecular weight of PEG coupled, the more stable was the PEG-IgG hybrid obtained concerning interfacial exposure and heating. The hybrid was stable against lyophilization and acid treatment and its stability was independent of the PEG molecular weight. The decrease in antigen binding ability was suppressed as much as possible by the use of a small amount of PEG of higher molecular weight. The PEG-IgG hybrids were further assessed as a stabilizer for IgG. A limited degree of PEG coupling was required for the hybrids to achieve the most efficient stabilization of IgG; the optimal PEG contents of the hybrid were greater than 20 wt% (interfacial exposure), about 5 wt% (heating), 20 wt% (lyophilization), and 10 wt% (acid treatment) for PEG 5600. It was also confirmed that the PEG-IgG hybrid was superior to PEG and human serum albumin as a stabilizer.

Interactions of human serum albumin with a modified poly(vinyl alcohol) gel packing for high-performance liquid chromatography

The interactions of human serum albumin (HSA) with a poly(vinyl alcohol) gel packing (Asahipak GS-520) for high-performance liquid chromatography of proteins were investigated. Under certain conditions, the elution of HSA from the GS-520 column was retarded and its chromatogram was split into two peaks, indicating weak adsorption of HSA onto the gels and also the existence of two subfractions, i.e. human mercapto-albumin (HMA) and human non-mercapto-albumin (HNA). The chromatograms were confirmed to be greatly influenced by the salt composition, the pH, and the temperature of the isocratic mobile phase. It is characteristic for the adsorption of HSA onto the gels to be suppressed at a pH near its isoelectric point. The HSA-gel interaction parameters calculated using an adsorption chromatography theory demonstrate that the adsorption of HSA is caused by enthalpy-driven interactions, which are depressed by lowering the pH, in addition to hydrophobic interactions. Under the recommended chromatographic conditions for high resolution of HMA/HNA, it was found that the HSA samples possessed some subfractions besides HMA and HNA fractions.

[A cytologic diagnosis of breast secretions--application of cytology to the mass survey of breast cancer]

From January 1982 to March 1987, an exfoliative cytological examination of abnormal nipple discharge was carried out on 790 patients. Of 22 histologically confirmed mammary carcinomas, 7 cases (31.8%) were diagnosed as positive by conventional cytologic techniques. By using the concentration method, in which the nipple secretion was collected in a series of testings that lasted 3 to 5 days and stored in a glass tube containing a fixative, the diagnostic accuracy was seen to increase significantly and 9 out of 15 malignant cases (60.0%) were accurately diagnosed as having cancer. Moreover, all 5 cases without any palpable mass were found to be positive by the smears made by this procedure.

A new intact immunoglobulin for intravenous use stabilized by chemically modified gelatin derivatives

The stabilization of human immunoglobulin (IgG) by chemically modified gelatins (Haemaccel and Gelofusine) was investigated. The gelatins prevented IgG from aggregation induced by exposure to interfaces and lyophilization. The stabilization effects of the gelatins were significantly larger than those of amino acids or sugars. These investigations led to the large-scale production of an immunoglobulin preparation for intravenous use in the clinic. The clinical product meets the Japanese minimum requirements for immunoglobulin preparations for intravenous use, and the long-term preservation of this new freeze-dried preparation has demonstrated its stability.

Cryptotia: our classification and treatment

Our classification of cryptotia is based on recognition that the deformity is the result of an anomaly of the intrinsic transverse and oblique auricular muscles. Our treatment, in the first instance, is a non-surgical correction. This should be started early, if possible in the first 6 months of the baby's life. Even in the case of older children, success can sometimes be achieved and a non-surgical correction should be considered first. If non-surgical management fails the deformity can be corrected surgically by dividing the muscle fibres that produce the anomaly of the external ear through a small incision. Our new surgical approach involves moving the available skin in the region of the inferior cephalo-auricular sulcus to the superior part where skin is needed by a rotation flap. This operation has several advantages.

Physicochemical and biological properties of poly(ethylene glycol)-coupled immunoglobulin G

In order to develop a new intravenous immunoglobulin G (IgG), IgG was covalently coupled to poly(ethylene glycol) previously activated by cyanuric chloride. The poly(ethylene glycol) coupled IgG obtained was studied for physicochemical and biological properties such as molecular structure, size-exclusion chromatographic behaviour, surface activity, interfacial aggregability, heat aggregability inducing nonspecific complement activation, and antigen-binding activity. The poly(ethylene glycol) coupling to IgG increased the apparent Stokes' radius and the surface activity of IgG and stabilized IgG on heating and/or on exposure to interface, while no structural denaturation of IgG was observed. The suppressed nonspecific aggregability was interpreted mainly by difficulty in association between the modified IgG molecules. These results indicated the use of the poly(ethylene glycol)-coupled IgG as an intravenous preparation and also as an additive stabilizing intact IgG for intravenous use.

Nonsurgical correction of congenital auricular deformities in the early neonate: a preliminary report

We conclude that auricular deformities of the early neonate are corrigible by nonsurgical correction. Ideally, the correction should be started immediately after birth (realistically, at latest by the third day after birth) in order to obtain satisfactory and irreversible results.

High-performance ion-exchange chromatography of plasma proteins

The use of anion-exchange high-performance liquid chromatography columns for the analysis of plasma proteins has been investigated. Mono Q and Polyanion SI were used as anion-exchangers. Several factors, including solvent composition, pH, flow-rate, sodium chloride linear concentration gradient and sample loading capacity, were examined for their effects on the resolution of protein standards and pooled human plasma (PHP). PHP was separated into ten or more protein fractions by a Mono Q column (50 X 5 mm I.D., flow-rate 2 ml/min) within 10 min. Components analysis of each fraction was performed using immunochemical methods and size-exclusion high-performance liquid chromatography. The Mono Q column was applied to the analysis of IgG myeloma and other patient plasma samples.

A denuded "turn-over" deltopectoral flap combined with a latissimus dorsi myocutaneous flap in the repair of extensive radionecrosis of the chest wall

For a one-stage repair of large and deep radionecrotic ulcers over the chest wall, we have used a denuded "turn-over" deltopectoral flap combined with a latissimus dorsi myocutaneous flap. With this technique we can easily cover a defect measuring over 20 x 20 cm. The deformity of the donor site on the contralateral infraclavicular region is minimal. Three illustrative cases are presented.

Cleavage of human serum immunoglobulin G by an immobilized pepsin preparation

In order to obtain an efficacious and safe immunoglobulin G (IgG) preparation for intravenous use, the digestion of IgG with an immobilized pepsin (EC 3.4.23.1) preparation was studied. Thus, pepsin was immobilized onto glutaraldehyde-activated AH-Sepharose 4B under acidic conditions. THe enzymatic properties, such as proteolytic activity, pH-activity profile and heat stability, of the immobilized pepsin preparation were examined. The immobilized pepsin retained more than 40% of its proteolytic activity toward N-acetyl-L-phenylalanyl-L-3,5-diiodo-tyrosine and more than 30% toward IgG, and also remarkable stability as compared with free pepsin. The immobilized pepsin thus prepared was efficiently used for the limited cleavage of IgG and the gel-filtration effect of the column made it easily possible to yield the F(ab')2-rich fraction for intravenous use.