EFFECT OF UNDILUTED PASSAGE ON THE POLYPEPTIDES OF MEASLES-VIRUS

Measles virus induces a large polypeptide (L; mol. wt. 180 K), a large glycopolypeptide (H; mol. wt. 80 K), a nucleocapsid associated polypeptide (P; mol. wt. 70 K), a nucleocapsid polypeptide (N; mol. wt. 60 K), a second glycopolypeptide (F(0); mol. wt. 60 K), a matrix or membrane polypeptide (M; mol. wt. 37 K) and a small polypeptide (S; mol. wt. 15 K). The second glycopolypeptide (F(0)) appears to be cleaved in purified measles virus. Defective interfering particles accumulate during passage of measles virus leading to a decrease in the amounts of virusspecific protein synthesized in infected cells. Even in the best preparations of purified measles virus, host proteins are always detected and these become more predominant in preparations with low infectivity.