Influence of Process Conditions on Measles Virus Stability

Abstract

Recombinant measles viruses are currently tested in clinical trials as oncolytic agent to be applied in cancer therapy. Contrary to their use as vaccine where 10 3 infectious virus particles per dose are needed, for cancer therapy 10 9 virus particles should be provided per dose. This leads to other challenges for the production process when compared to vaccine production. This study presents measles virus stability with regard to conditions during production and storage of the virus. Relevant process parameters such as temperature (4-37°C), pH (pH 4-11), conductivity (1.5 to 137.5 mS cm ) and oxygen partial pressure were analyzed. The infectivity of measles virus particles decreased highly at 37 and 32°C, while at 22 and 4°C it remained stable for several hours or even days, respectively. The thermal inactivation reactions followed first order kinetics and the thermodynamic parameters enthalpy and entropy were estimated. Towards changes in pH measles virus particles were very sensitive, while no inactivation could be observed with varying conductivity. Measles virus incubation at an oxygen partial pressure of 100% did not lead to any loss of infectivity. The results show which parameters should be considered and controlled strongly in the production process to further raise measles virus yields for the high amount needed in cancer therapy approaches.

Concepts for the Production of Viruses and Viral Vectors in Cell Cultures

“…This higher cholesterol content leads to a lower stability [54,55]. In contrast, measles viruses showed a higher stability produced at 32°C [53]. The bioreactor system must eliminate as many factors as possible that reduce virus yields and should provide a suitable environment for the cells, avoiding additional stress caused by shear forces or nutrient limitation.…”

“…Typically, animal cell lines show the highest growth rate at a process temperature of 37°C. However, at 37°C, measles virus and retroviruses have half-lives of approximately 1 h and 6-7 h, respectively [46,53]. There are two realistic options to avoid thermal inactivation: (a) reducing the process temperature or (b) harvesting the virus continuously, thereby achieving the rapid and efficient cooling of the product stream.…”

High titer oncolytic measles virus production process by integration of dielectric spectroscopy as online monitoring system

“…However, neither process can yet provide the concentrations of active Measles virus required for therapeutic applications. Although enveloped viruses in general are sensitive to changes in osmolality, some reports indicate that Measles virus is comparatively robust, whereas others confirm its sensitivity (Sviben et al, 2016;Weiss et al, 2013). Measles viruses are sensitive to low pH and UV light, as is typical for enveloped viruses (Grein, Michalsky, & Czermak, 2014;Sviben, Forčić, Kurtović, Halassy, & Brgles, 2016;Weiss et al, 2013).…”

“…This may in part reflect the low stability of the viral particles. At the optimal growth temperature of the host cell lines (37°C), the Measles virus has a half-life of only 1 hr (Weiss et al, 2013). Although enveloped viruses in general are sensitive to changes in osmolality, some reports indicate that Measles virus is comparatively robust, whereas others confirm its sensitivity (Sviben et al, 2016;Weiss et al, 2013).…”

Screening different host cell lines for the dynamic production of measles virus

“…Such high titers are necessary because the therapeutic efficacy of MV is reduced by the patient's immune response, particularly in patients that have previously been vaccinated against measles . MV is also naturally unstable in vivo , and hence it is also sensitive to the production conditions in vitro . The virus particles are denatured at high temperatures and acidic pH (< 6).…”