Enhancing effect of halogenated pyrimidines [BUdR and IUdR] on the growth of rubella virus in BHK-21 cells

Abstract

Rubella infected BHK-21 cell cultures although useful in immunofluorescence work have, as a rule, a very lout number of cells containing rubella virus antigen. This often presents a difficulty in reading the tests, particularly when a serum sample is being assayed for the presence of rubella specific antibodies in the IgM fraction of immunoglobulins.The reason for such a low percentage of infected cells, usually around 2 per cent, exhibiting rubella antigen is not quite dear. It has been suggested, however, that interferon or other cell products may be responsible for the inhibition of virus replication. In this connection it has been reported that production of interferon can be overcome by treating the cells with 5-iodo-2'-deoxy~dridine [IUdR] (1). It has also been reported that IUdl~ and 5-bromo-deoxyuridine [BUdR] are capable of activating the synthesis of both t~NA and DNA containing viruses (2,3,4,5).In view of the above observations, an attempt was made to determine if treatment of BHK-21 cells with these halogenated pyrimidines will increase the number of rubella antigen containing cells. The results of this investigation are reported here.BHK-21 ceil cultures were grown as monolayers in 30 ml Falcon plastic bottles, and were used for inoculation when each bottle contained approximately 6 • 105 cells. The inoculum per bottle was 0.5 ml, containing 5 • 10 a IND50 of rubella virus strain 1~-23.After 90 minutes of adsorption period at 36 ~ C, each inoculated culture received 5 ml of Eagle's minimum essential medium supplemented with 2 per cent fetal calf serum, and with or without halogenated pyrimidine, depending on the design of the experiment. After incubation for 24 hours at 36 ~ C and 72 hours at 33 ~ C, the infected monolayers were treated with trypsin-versene. The monodispersed cells were used for preparation of smears on glass coverslips. The smears were airdried, washed once in PBS and fixed in cold acetone (--20 ~ C) for 10 minutes. After allowing to drain, the smears were used for immunofluorescent staining.

Simian rotavirus SA-11 plaque formation in the presence of trypsin

“…Addition of halogenated pyrimidines to virusinfected cell cultures has been shown to overcome interferon production (10). Activation of the synthesis of both RNA and DNA viruses has also been reported in the presence of 5-bromodeoxyuridine (20,24). Incorporation of this substance in the overlay produced no noticeable effect on the plaque-forming ability of SA-11 virus in MA-104 cells.…”

Enhanced SV40-virus replication in Chinese hamster kidney cells pretreated with 5-iodo-2?-deoxyuridine

“…Pretreatment did not increase SV40 replication in fully permissive monkey kidney and nonpermissive Syrian hamster or mouse embryo cells. , Recent publications (2,7,8,9,10,11) have demonstrated that treatment of cells with the thymidine analogue 5-iodo-2'-deoxyuridine (IUDR) before infection with different viruses (human and murine eytomegalovirus, human adenovirus 7 and Rubella virus) increases viral replication. In the present report we show that the prior treatment of semipermissive Chinese hamster kidney (CHK) cells (3,4) by IUDR can enhance their ability to replieate Simian virus 40 (SV40).…”