Removal of hepatitis B virus from a concentrate of coagulation factors II, VII, IX and X by hydrophobic interaction chromatography

The effects of ligand chain length, salt concentration and temperature on the adsorption of bovine serum albumin onto polypropyleneglycol-Sepharose

The interaction thermodynamics associated with bovine serum albumin adsorption on polypropylene glycol (n=3)-Sepharose CL-6B and polypropylene glycol (n=7)-Sepharose CL-6B, using ammonium sulfate as the modulator was studied. Analysis of data under linear conditions was accomplished with the stoichiometric displacement retention model, preferential interaction approach and van't Hoff plots applied to HIC systems. Preferential interaction analysis indicated a strong entropic driving force under linear conditions, due to the release of a large amount of solvent on adsorption. In contrast, flow microcalorimetry under overloaded conditions showed that the adsorption of bovine serum albumin may be entropically or enthalpically driven. It is postulated that adsorption in the nonlinear region is influenced by the degree of water release, protein-protein interactions on the surface, reorientation of ligand, and conformational changes in the protein.

Effect of salts and temperature on the adsorption of bovine serum albumin on polypropylene glycol-Sepharose under linear and overloaded chromatographic conditions

The interaction thermodynamics associated with bovine serum albumin (BSA) adsorption on polypropylene glycol (PPG)-Sepharose CL-6B gel, using ammonium and sodium sulfate was studied. Analysis of data under linear conditions was accomplished with the stoichiometric displacement retention model and preferential interaction approach. Preferential interaction analysis indicated a strong entropic driving force due to the release of a large amount of solvent on adsorption. Flow microcalorimetry provided direct heat of adsorption measurements under overloaded conditions and confirmed that the adsorption of BSA on PPG-Sepharose was entropically driven within the range of conditions studied. Using these data in combination with isotherm measurements, it is shown that protein surface coverage, salt concentration, salt type and temperature affect the enthalpic and entropic behavior in hydrophobic interaction chromatography (HIC). This study shows that protein-sorbent interactions can be strongly influenced by the degree of water release, protein-protein interactions on the surface, and the re-orientation and/or reconfiguration of the adsorbed protein.

Study of hydrophobic interaction adsorption of bovine serum albumin under overloaded conditions using flow microcalorimetry

The adsorption behavior of bovine serum albumin (BSA) on a Sepharose based hydrophobic interaction support has been studied. Flow microcalorimetry has been used to determine the heat of adsorption under overloaded chromatographic conditions. These data have been complemented with capacity factor and isotherm measurements to provide insight on the mechanisms of adsorption. The heat of adsorption data have confirmed that the hydrophobic interaction adsorption of BSA under linear isotherm conditions is driven by entropy changes. Under overloaded (non-linear) conditions, however, it has been shown that the changes in enthalpy can drive adsorption; this behavior is not evident from analyses of capacity factor data. It is postulated that for BSA adsorption on the Sepharose derivative of interest, attractive force interactions between adsorbed protein molecules drive the adsorption process under overloaded conditions in a high (NH4)2SO4 environment. It is further postulated that these interactions are due to a change in confirmation of the adsorbed protein under these conditions.

Inactivation of viruses found with plasma proteins

Plasma protein solutions such as albumin and intramuscular immune globulin have long histories of viral safety. Coagulation factor concentrates as traditionally manufactured frequently transmitted HBV, HCV, and HIV. Indeed, it is probable that every vial of concentrate contained infectious HCV. Modern coagulation factor concentrates have a greatly improved safety record arising, principally, from the implementation of virucidal procedures. It is interesting to note that the same methods that failed to substantially reduce NANBHV transmission in clinical studies are those that were found to inactivate less than 10(4) ID50 of HIV, HBV, and/or HCV in preclinical studies (Table 17-5). Implementation even of these methods nearly eliminated the transmission of HIV by coagulation factor concentrates. A summary of the results of the most successful procedures is given in Table 17-10. The results show 0/564 patients had evidence of HIV transmission, 6/151 patients had evidence of HBV transmission, and 2/301 patients had evidence of HCV transmission. As compared with those procedures described in Table 17-5, the greater kill of HIV, HBV, and NANBHV demonstrated preclinically, and the improved clinical results, are most notable. The data, examined in terms of units transfused, are presented in Figure 17-1. Since the average adult hemophiliac in the United States receives 80,000 units of clotting factor per year, the best of the concentrates show safety over the equivalent of at least 10-human-years of treatment. Are the best of today's coagulation factor concentrates safe from the transmission of HBV, NANBHV (including HCV), and HIV. Given the limited number of patients eligible for clinical studies, and the length, difficulty, and expense of such studies, the best answer comes from a knowledge of the initial virus load coupled with information regarding virus removal, serendipitous inactivation, and intentional sterilization. A recently completed analysis of these factors (Horowitz 1990) indicates that the best of the modern coagulation factor concentrates are likely to be as safe as albumin (Figure 17-2).

Purity, antigenicity and immunogenicity of the hepatitis B surface antigen purified by five different methods

Five published methods for the purification of HBsAg from plasma were compared for specific activity (SA), degree of purification, and yield. The SA value was determined by dividing the reciprocal of the end point dilution per milliliter as determined using a commercial radioimmunoassay (AUSRIA II; Abbott Laboratories, North Chicago, IL) by the protein concentration quantitated by the Lowry method. HBsAg purified by two consecutive isopycnic ultracentrifugation separations in KBr and one rate-zonal separation in sucrose using a zonal rotor (Ti-14, Beckman, Palo Alto, CA) yielded a preparation which gave the highest SA value, degree of purification and yield as compared to four other methods. Each purified preparation was adsorbed to alum adjuvant and injected into mice to determine the immunogenic dose at which 50% of the animals elicited an anti-HBs response (ID50). The zonal rotor method resulted in the lowest ID50 value (365 ng/ml) supporting the highest SA value. Furthermore, SDS polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis revealed that this preparation had the greatest number of HBsAg-specific polypeptides (N = 7) and the fewest contaminating polypeptides (N = 5). The contaminating proteins were identified as alpha-2-macroglobulin, heavy chains of IgG and IgM, immunoglobulin kappa chain, and albumin.

Binding of hepatitis virus particles to immobilised procion blue-HB and cibacron blue 3GA

Two chemically similar triazine dyes, coupled to chromatographic gels, have been investigated for their ability to bind and retain hepatitis B surface antigen marker of the hepatitis B virus. Both dyes, Procion Blue-HB and Cibacron Blue 3GA, were effective in removing viral particles from plasma protein solutions. A number of combinations of dye and gel support have been tried, to obtain optimal binding. A Cibacron Blue-Trisacryl adsorbent achieved almost complete retention (greater than 99.5%) of HBsAg before breakthrough occurred. Binding was better at reduced flow rates and on large pore gel matrices, suggesting that steric restrictions limit the interaction. The interaction is directly between immobilised dye and the viral particle, rather than through plasma albumin, which also binds to these affinity adsorbents. These findings are important in the use of immobilised triazine dyes for plasma protein purification. Furthermore, the interaction may be utilised either for the removal of HB viral particles from plasma or as a rapid method of their purification.

Hepatitis B virus associated DNA polymerase inactivation in factor IX concentrates

Inactivation of Hepatitis B virus associated DNA polymerase was studied in factor IX concentrate (coagulation factors II, VII, IX and X) by heat pasteurization (60 degrees C, 10 hr) and by alkylating agents iodoacetic acid and iodoacetamide. DNA polymerase appeared to reach a residual level which occurred in human serum albumin at 60 degrees C, 10 hr under comparable spike level of hepatitis B virus. Of the four coagulation factors, factor IX activity was most susceptible to inactivation procedures with 40-50% recovery across heat pasteurization and approximately 70% recovery across iodoacetic acid treatment. Factor IX specific activities of the treated concentrates were greater than or equal to 70% of the untreated controls with no appreciable change of corresponding NAPTT values. Factor IX concentrates subjected to such inactivation procedures should reduce the potential for hepatitis B virus transmission.

Hepatitis B virus, hepatitis non-A, non-B virus and hepatitis delta virus in lyophilized antihemophilic factor: relative sensitivity to heat

Lyophilized plasma derivatives are more stable to heat than when they are in the liquid state. Commercial Factor VIII (antihemophilic factor) was seeded with a measured quantity of hepatitis B virus. The contaminated material was then lyophilized and subjected to heat of 60 degrees C for 30 hr. Chimpanzees were inoculated with the heat-treated antihemophilic factor or sham-treated antihemophilic factor that had been held at 4 degrees C. Surprisingly, hepatitis B virus survived the heating procedure with no apparent loss in titer: the incubation period to appearance of HBsAg was that expected for the challenge dose of virus. Even more surprising, one chimpanzee (the recipient of the unheated antihemophilic factor) also developed non-A, non-B hepatitis and two chimpanzees (recipients of the heated antihemophilic factor) also developed delta hepatitis. Neither of these agents was a contaminant of the hepatitis B virus challenge pool, since the purity of this hepatitis B virus pool was established previously in chimpanzees. Thus, both a non-A, non-B agent and the delta agent apparently contaminated the commercial antihemophilic factor. This is the first direct evidence for contamination of antihemophilic factor with the delta agent and confirms previous seroepidemiologic evidence for its presence in pooled plasma derivatives. Subsequent inactivation studies were performed with antihemophilic factor experimentally contaminated with the Hutchinson strain of non-A, non-B hepatitis virus. In these studies, heating at 60 degrees C for 30 hr in the dry state rendered antihemophilic factor free of detectable non-A, non-B hepatitis virus.

Removal of non-A, non-B hepatitis virus from a concentrate of the coagulation factors II, VII, IX and X by hydrophobic interaction chromatography

The efficacy of a chromatographic procedure based on hydrophobic interaction chromatography to remove non-A, non-B (NANB) infection from a concentrate of coagulation factors II, VII, IX and X (Preconativ, KabiVitrum AB) was evaluated in chimpanzees. For this purpose, NANB infective human plasma (H-strain) was deliberately added to a solution of Preconativ (45 IU factor IX:C/ml) to reach a titre of NANB virus of greater than or equal to 10(2) chimpanzee infectious doses (CID)/ml. The NANB-contaminated preparation was chromatographed on octanohydrazide-Sepharose 4B at a high salt concentration. Groups of 2 chimpanzees were each inoculated intravenously with 45 IU factor IX:C of Preconative before and after this virus adsorption chromatographic step. The experimental animals remained free of any serological and biochemical evidence of hepatitis during a 12-month follow-up period. One of the two control animals developed clear evidence of NANB hepatitis.

Adsorption properties of different hepatitis B virus related antigens (HBsAg, HBcAg, HBeAg) on octanohydrazide-Sepharose 4B

Chromatography of plasma containing hepatitis B virus and partially purified viral antigens on a hydrophobic gel derivative (octanohydrazide-Sepharose 4B) revealed that HbsAg and HbcAg were adsorbed to the gel in 0.75 mol/l ammonium bicarbonate and eluted by a detergent, Berol. HBeAg in a purified HBcAg preparation from human liver, but not HBeAg in plasma, was bound to the gel. Furthermore, HBeAg in the HBcAg preparation, but not HBeAg in plasma, lost its antigenic reactivity in the presence of Berol, indicating that the two HBeAgs were present in different molecular configurations. However, HBeAg could be released from HBV (HBcAg) and form a component which sedimented slowly and was immune-reactive in the presence of the detergent. The results contribute to knowledge of the interrelationship between hepatitis B-related antigens and indicate that chromatography on hydrophobic gel derivatives can be used not only for the purification (and removal) of HBsAg but also of HBcAg.