1MUA-18 
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c. lOyg of DN ' ase-treated DNA will be plated with JE. col i 
DP-50 supF. 
d. If the medium remains sterile and no -plaques are seen, 
P-lambda DNA will be removed from the Class III cabinet 
and the P4 facility by the procedures described in 
IX(B)lCi or IX(B)lCii above. 
4. Serum 
a. Serum samples will be heated at 60C for 30 minutes. 
b. Undiluted samples (0.05 ml) will be added to L broth as 
described above. 
c. If the cultures are sterile, the sera will be removed from 
the Class III cabinet and Building 550, FCRC, as described 
in IX(B)lCii above. 
d. A 0.05 ml serum sample derived from animals exposed to P-X 
vectors will be plated with E_. col i DP-50 supF. If no 
plaques develop, the serum sample can be considered free 
of P-A phage. 
[Appendix C — 241] 
