Comparison of Porcine Reproductive and Respiratory Syndrome Virus Growth in Media Supplemented with Fetal Bovine Serum or a Serum Replacement

Abstract

Abstract. Commercially available serum replacements are often used in cell culture as a cheaper and less variable substitute for fetal bovine serum (FBS). The growth of porcine reproductive and respiratory syndrome virus (PRRSV) isolates in CRL11171 cells maintained in a medium supplemented with FBS was compared with virus propagation in the same cell line maintained in the same medium with a serum replacement. The PRRSV replicated significantly better when the cell culture medium was supplemented with FBS. The results of this study have implications for the use of serum replacement-supplemented medium for PRRSV diagnosis by virus isolation.Porcine reproductive and respiratory syndrome virus (PRRSV) was first isolated in Europe on primary porcine alveolar macrophages (PAM) and was designated Lelystad virus. 9 The first US PRRSV isolate was isolated on a continuous cell line, ATCC CL2621. 3 In addition to PAM cultures 9 and the CL2621 cell line, 3 the MARC 145 7 and ATCC CRL11171 8 cell lines also support PRRSV replication. Both US and European PRRSV isolates replicate well in PAM cultures, but the difficulties and expense in obtaining these cells limit their use. Therefore, a continuous cell line is most often used to isolate and propagate PRRSV.Virus isolation is a commonly used method for the detection of PRRSV infection in many diagnostic laboratories. Clinical and diagnostic laboratories that maintain cell cultures for virus isolation can be affected by the cost and availability of fetal bovine serum (FBS). 6 Because FBS carries the risk of contamination with bovine viruses, batch-to-batch variation, and increased expense, a serum replacement is desirable, particularly in clinical and diagnostic settings. Commercially available serum replacements are often used as a substitute for FBS.Previous studies of serum replacements have shown variable results in their ability to support the growth of cell cultures and to replicate virus. Thus, the adaptability of cell lines to serum replacements and the capability of the cell line to propagate virus must be examined on an individual basis. 2,6 The variation in PRRSV propagation on various cell types has been reported, but differences due to medium or medium supplement changes have not been reported. 1,7 In this study, the growth of PRRSV isolates in CRL11171 a cell cultures maintained with either FBS or a serum replacement b was compared.To compare the replication of PRRSV with both supplements, CRL11171 cells were split into 2 populations, 1 maintained in Dulbecco's modified Eagle medium (DMEM) containing 10% FBS and the other maintained in DMEM supplemented with 10% serum replacement. After 3 passages in the respective supplemented medium, confluent monolayers of both cell populations were grown on 12-well plates. The cells showed no difference in growth rates or morphology regardless of the serum supplement used (data not shown). The CRL11171 monolayers were infected in triplicate with the 11th passage of VR-2385, a well-characterized virulent US PRRSV isolate, at...

Potent Oncolytic activity of human enteroviruses against human prostate cancer

“…Similar to the above findings, despite the presence of varying levels of ICAM-1, DAF, and alpha 2 beta 1 on peripheral blood lymphocytes, they remain refractile to infection with CVA21 at multiplicity of infection 200 times greater than used to infect melanoma cells [4] and are also refractile to infection with EV1 [8]. The oncolytic capacity of CVA21 is minimally altered when PC3 cells were grown in two alternative mediums, KSFM or RMPI-1640 (data not shown), suggesting that the reduced susceptibility of the non-malignant line RWPE-1 to all three enteroviruses was not the result of reduced viral capacity in an alternative serum-free medium, known to occur for other viruses [43,44]. As enteroviruses are considerably stable in extreme pH parameters [45], it is unlikely that alterations in environmental pH will affect the oncolytic capacity of the enteroviruses in vivo.…”