Jens Modrof

West Nile Virus Neutralization by US Plasma-Derived Immunoglobulin Products

The 1999 introduction of West Nile virus (WNV) into the United States has resulted in the largest epidemic of arboviral illness in the Western Hemisphere, with an estimated 2.5 million cases of mostly asymptomatic human infections since then. As a consequence, an increasing occurrence of WNV antibodies in plasma collected in the United States, and thus in intravenous immunoglobulin (IVIG) products, can be expected. Using an in vitro assay to investigate antibody function, rather then presence, almost 1000-fold differences in neutralization capacity were demonstrated between individual IVIG lots. In a mouse model of lethal WNV infection, treatment with IVIG of a higher WNV antibody titer protected recipients, whereas mice treated with control IVIG died. IVIG lots with higher WNV antibody titers would seem to be desirable for substitution therapy for people with immunodeficiencies.

Neutralization of human parvovirus B19 by plasma and intravenous immunoglobulins

BACKGROUND: Human parvovirus B19 (B19V) is a highly prevalent pathogen, and plasma pools for manufacturing of plasma‐derived products have been shown to contain antibodies against B19V (B19V immunoglobulin G [IgG]).

Hepatitis A virus antibodies in immunoglobulin preparations

BACKGROUND Persons with primary immune deficiency receive intravenous immunoglobulin (IVIG) as antibody replacement therapy. These patients depend on the presence of protective antibody levels against circulating pathogens in IVIG. OBJECTIVES The incidence of hepatitis A virus (HAV) infections has been decreasing globally. We investigated whether this decrease in HAV incidence is reflected in human plasma pools and evaluated whether HAV antibody titers in IVIG preparations are still adequate for antibody replacement. METHODS By using ELISA, the HAV antibody titer of 3,953 plasma pools sourced from March 2003 through September 2008 in the European Union (EU) or United States (US) and of 169 IVIG lots manufactured from 2005 through 2007 was determined. The functionality of the HAV antibodies contained in IVIG was assessed by using a microneutralization assay. RESULTS The results confirm a decrease in HAV antibody titers in EU (-28%) and US (-41%) plasma. Furthermore, the mean HAV antibody content in EU (1.70 +/- 0.12 IU/mL) and US (0.82 +/- 0.09 IU/mL [mean +/- SEM]) plasma was significantly different (P = .0001). A significant difference (P < .0001) was also evident in the IVIG preparations KIOVIG (22.91 +/- 0.68 IU/mL) and Gammagard Liquid (14.60 +/- 0.48 IU/mL), respectively, made from EU or US plasma. In accordance with the ELISA results, there was a significant difference (P < .0001) in HAV neutralization titer 50% (NT(50)) values between IVIG produced from EU-sourced (2,477 +/- 265 NT(50) [1:X]) or US-sourced (844 +/- 82 NT(50) [1:X]) plasma. CONCLUSION Although HAV antibody seroprevalence continues to decrease in Europe and the US, HAV antibody titers in IVIG lots appear to remain adequate for antibody replacement therapy.

West Nile virus infection in plasma of blood and plasma donors, United States.

This study investigated the association of ongoing West Nile virus (WNV) infections with neutralizing antibody titers in US plasma-derived intravenous immune globulin released during 2003–2008. Titers correlated closely with the prevalence of past WNV infection in blood donors, with 2008 lots indicating a prevalence of 1%.

Hepatitis E virus and the safety of plasma products: investigations into the reduction capacity of manufacturing processes

Hepatitis E virus (HEV) has been transmitted by transfusion of labile blood products and the occasional detection of HEV RNA in plasma pools indicates that HEV viremic donations might enter the manufacturing process of plasma products. To verify the safety margins of plasma products with respect to HEV, virus reduction steps commonly used in their manufacturing processes were investigated for their effectiveness to reduce HEV.

Chikungunya virus and the safety of plasma products

BACKGROUND: Chikungunya virus (CHIKV) outbreaks were previously restricted to parts of Africa, Indian Ocean Islands, South Asia, and Southeast Asia. In 2007, however, the first autochthonous CHIKV transmission was reported in Europe. High‐level viremia, a mosquito vector that is also present in large urban areas of Europe and America, and uncertainty around the resistance of this Alphavirus toward physiochemical inactivation processes raised concerns about the safety of plasma derivatives. To verify the safety margins of plasma products with respect to CHIKV, commonly used virus inactivation steps were investigated for their effectiveness to inactivate this newly emerging virus.

Virus inactivation during the freeze-drying processes as used for the manufacture of plasma-derived medicinal products

BACKGROUND: Freeze‐drying is a technology widely used during the production of plasma‐derived medicinal products. Several studies have shown that freeze‐drying can also result in virus inactivation and particularly of hepatitis A virus (HAV). To date, however, the variables critical for virus inactivation during freeze‐drying have not been investigated systematically.

Inactivation of parvovirus B19 during STIM-4 vapor heat treatment of three coagulation factor concentrates

BACKGROUND: To enhance the viral safety margins, nanofiltration has been widely integrated into the manufacturing process of plasma‐derived medicinal products. Removal of smaller agents such as parvovirus B19 (B19V) by filtration, however, is typically less efficient. Because recent investigations have demonstrated that B19V may be more heat sensitive than animal parvoviruses, the potential B19V inactivation by a proprietary vapor heating procedure (STIM‐4) as incorporated into the manufacturing processes of several nanofiltered coagulation factor concentrates was investigated.

Inactivation of hepatitis A variants during heat treatment (pasteurization) of human serum albumin

BACKGROUND: Pasteurization of human serum albumin (HSA) is detailed in the US and European Pharmacopoeial monographs and therefore a process that allows for little variation in physiochemical variables. Nevertheless, differences of up to 3.9 log in hepatitis A virus (HAV) inactivation by pasteurization have been reported. Here, the hypothesis that the choice of HAV variant used in the pasteurization might contribute to this inactivation variability is evaluated experimentally.

Reduction of spiked porcine circovirus during the manufacture of a Vero cell-derived vaccine

Porcine circovirus-1 (PCV1) was recently identified as a contaminant in live Rotavirus vaccines, which was likely caused by contaminated porcine trypsin. The event triggered the development of new regulatory guidance on the use of porcine trypsin which shall ensure that cell lines and porcine trypsin in use are free from PCV1. In addition, manufacturing processes of biologicals other than live vaccines include virus clearance steps that may prevent and mitigate any potential virus contamination of product. In this work, artificial spiking of down-scaled models for the manufacturing process of an inactivated pandemic influenza virus vaccine were used to investigate inactivation of PCV1 and the physico-chemically related porcine parvovirus (PPV) by formalin and ultraviolet-C (UV-C) treatment as well as removal by the purification step sucrose gradient ultracentrifugation. A PCV1 infectivity assay, using a real-time PCR infectivity readout was established. The formalin treatment (0.05% for 48h) showed substantial inactivation for both PCV1 and PPV with reduction factors of 3.0log10 and 6.8log10, respectively, whereas UV-C treatment resulted in complete PPV (≥5.9log10) inactivation already at a dose of 13mJ/cm but merely 1.7log10 at 24mJ/cm(2) for PCV1. The UV-C inactivation results with PPV were confirmed using minute virus of mice (MVM), indicating that parvoviruses are far more sensitive to UV-C than PCV1. The sucrose density gradient ultracentrifugation also contributed to PCV1 clearance with a reduction factor of 2log10. The low pH treatment during the production of procine trypsin was investigated and showed effective inactivation for both PCV1 (4.5log10) and PPV (6.4log10). In conclusion, PCV1 in general appears to be more resistant to virus inactivation than PPV. Still, the inactivated pandemic influenza vaccine manufacturing process provides for robust virus reduction, in addition to the already implemented testing for PCV1 to avoid any contaminations.