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ADDITIONAL PROPERTIES OF THE MEF1 STRAIN OF POLIOMYELITIS VIRUS, ESPECIALLY WITH REFERENCE TO ATTEMPTS AT CULTIVATION IN THE CHICK EMBRYO

Robert H. Yager, Peter K. Olitsky, O. Lahelle
1949 Journal of Bacteriology  
Succesful cultivation in fertile hens' eggs has been reported of Theiler's virus, TO, FA, GDVII strains, but not of poliomyelitis virus, Lansing, Y-SK, Ph, and several other human strains (Riordan and Sa-Fleitas: J. Immunol., 56, 263, 1947; Dunham and Parker: J. Bact., 45, 80, 1943; and others). These findings on TO, FA, and GDVII and on Lansing viruses have been confirmed in this laboratory. In view of the fact that multiplication in chick embryos is a distinct feature separating so-called
more » ... ating so-called murine from poliomyelitis viruses and since the MEF1 strain (Schlesinger, Morgan, and Olitsky: Science, 98, 452, 1943) has not as yet been studied in this regard, the present report on such studies including certain other properties is presented. Chick embryos, 7 to 11 days old, were inoculated with a 20 per cent MEF1 virus as a mouse brain suspension, 0.03 ml intracerebrally, 0.25 ml into the yolk sac, or 0.1 ml on the chorioallantoic membrane (C.A.). The membranes were then incubated for 7 to 11 days, the yolk sacs for 11 days, and the intracerebral series, 7 days. The C.A. or embryo (or both) and brain in 101 dilution were subinoculated intracerebrally in mice. Blind passage from the inoculated embryos to 2 or more series of normal chick embryos was made along with subinoculation in mice. The result was that MEF1 virus was found to be incapable of multiplying in chick embryos even intracerebrally. It is of interest that in one instance in the C.A.-inoculated series the membrane in 10-1 dilution induced paralyses in the mice. Although the mouse brain virus was identified by positive neutralization with Lansing antiserum, it was proved by passage that the virus did not multiply in the membrane but that it only persisted in the inoculum. In addition, the MEF1 after a large number of mouse passages exhibits a higher LDro titer after intracerebral inoculation in the Rockefeller Institute strain of mice, viz., 3.0 to 4.2, than it does in the Lansing strain, which after many more mouse passages still shows the LDw titer not to exceed 3 and at times ILt. Colonel, V.C., U. S. Army. ' Fellow, Scientific Research Fund, Oslo, Norway. 12 [VOL. 58 NOTES on May 4, 2020 by guest
doi:10.1128/jb.58.1.112-113.1949 fatcat:vu6kzeekyvbiram2ljfifimg2i