RT Journal Article SR Electronic(1) A1 Krueger, Robert G.YR 1977 T1 Characterization of the C-type Virus Produced In Vitro by MOPC-21 BALB/c Myeloma JF Journal of General Virology, VO 37 IS 3 SP 475 OP 485 DO https://doi.org/10.1099/0022-1317-37-3-475 PB Microbiology Society, SN 1465-2099, AB SUMMARY The tissue culture-adapted P3 clone of MOPC-21 BALB/c myeloma cells produce a C-type virus, designated as MO21-MuMAV, that has many properties in common with the NB-tropic, C-type virus produced by a clone of the FLOPC-1 line of BALB/c myeloma (FL1-MuMAV) and one property that is distinctly different. On the one hand, both particles are extremely unstable as shown by their buoyant densities when analysed under different conditions of isopycnic gradient centrifugation; the enzymic activity of the virus RNA-dependent DNA polymerase is similar; the two viruses are similar antigenically; both viruses have similar XC syncytium-inducing activity; the endogenous RNA of both viruses contains poly(A) tracts of a similar length; both are NB-tropic as they productively infected BALB/3T3 and NIH/3T3 cells. However, the RNA of MO21-MuMAV consists of more high mol. wt. (60 to 70S) RNA species than does FL1-MuMAV RNA. In addition, MO21-MuMAV does not infect normal rat kidney cells as efficiently as does FL1-MuMAV. The NB-tropism of MO21-MuMAV does not appear to be due to a mixture of N- and B-tropic viruses on the basis of (a) the NB-tropism of the progeny virus produced by infected NIH/3T3 and BALB/3T3 cells; and (b) the dose-response relationship of MO21-MuMAV infection of BALB/3T3 and NIH/3T3 cells. Thus, the data suggest that different BALB/c myelomas produce C-type viruses that are very similar, but not necessarily identical., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-37-3-475