DMSO induces reactivation of cytomegalovirus in vitro from spleens of latently infected mice. Brief report

Dimethyl Sulfoxide Enhances Kaposi’s Sarcoma-Associated Herpesvirus Production During Lytic Replication

Kaposi’s sarcoma-associated herpesvirus (KSHV) is an etiologic agent of Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman disease. In studies of KSHV, efficient virus production and isolation are essential. Reactivation of KSHV can be initiated by treating latently infected cells with chemicals, such as 12-O-tetradecanoyl-phorbol-13-acetate and sodium butyrate. These chemicals have been used as tools to induce lytic replication and viral production in KSHV-producing cell lines. Dimethyl sulfoxide (DMSO) is an organosulfur compound that is frequently used as an aprotic solvent similar to water. In experiments exploring signaling pathways in KSHV-infected cells, DMSO treatment alone as a vehicle affected the lytic gene expression of KSHV. However, to the best of our knowledge, the effects of DMSO on KSHV-producing cells have not yet been reported. Therefore, in this study, we investigated whether DMSO could be used as a reagent to enhance viral production during lytic replication in KSHV-producing cells and assessed the underlying mechanisms. The effects of DMSO on KSHV production were analyzed in iSLK BAC16 cells, which have been widely used for recombinant KSHV production. We found that the production of KSHV virions was significantly increased by treatment with DMSO during the induction of lytic replication. Mechanistically, lytic genes of KSHV were enhanced by DMSO treatment, which was correlated with virion production. Additionally, DMSO induced the phosphorylation of JNK during lytic replication, and inhibition of JNK abolished the effects of DMSO on lytic replication and virion production. Our findings showed that additional treatment with DMSO during the induction of lytic replication significantly improved the yield of KSHV production.

Cytomegalovirus and latency: an overview

Cytomegalovirus (CMV) is a member of the herpes virus group. Infection results in a variety of disorders which depend largely on the immune status of the host. A well known property of CMV is that after primary infection the virus persists in the body of the host resulting in latency. Severe immunodepression or immunodeficiency can cause reactivation of the virus from its latent state, leading to endogenous reinfection. In contrast to other herpes viruses, such as herpes simplex virus which persists in neurons, and Epstein Barr virus which persists in B lymphocytes, little is known about the localization of latent CMV. In order to obtain more insight in the organ or cell type serving as a reservoir for latent CMV, it is important to know more about the course of natural infection and the cells and organs involved. When more information is available about the localization of latent virus, studies concerning the physical state of viral DNA or the extent of viral transcription and/or translation will follow in the near future. In this review some properties of the epidemiology and transmission of human CMV, as well as data about acute infection will be given. In addition, some characteristics of the localization of latent CMV and the physical state of the virus will be discussed. Where necessary, particularly regarding insight into CMV-host interactions, knowledge of animal, particularly murine, rat and guinea pig CMV infections, will be discussed.

Recovery of a herpesvirus from a roan antelope (Hippotragus equinus)

A herpesvirus was recovered in culture from the cells of a roan antelope (Hippotragus equinus) following cryopreservation in DMSO and it is thought that the DMSO may have been involved in reactivation. The virus was shown to be antigenically related to alcelaphine herpesvirus-1 (AHV-1) of wildebeest and ovine herpesvirus-2 (OHV-2) of domestic sheep (formerly designated the sheep-associated agent of malignant catarrhal fever (MCF]. Cloned DNA fragments of AHV-1 and OHV-2 cross hybridised with DNA prepared from cells infected with the roan antelope virus and the intensity of reaction suggested that this virus was more closely related to AHV-1 than is OHV-2. The virus represents the third gamma herpesvirus isolated from large African antelope and should be provisionally designated hippotragine herpesvirus-1. On inoculation into rabbits the virus induced malignant catarrhal fever indicating that roan antelope should be considered as a possible source of infection.