THE MAMMALIAN CELL-VIRUS RELATIONSHIP

Abstract

Sustained infection of HeLa cells by Coxsackie B3 virus, dependent on presence of viral inhibitor in culture medium, was achieved. Persistent treatment of carrier cultures with anti-Coxsackie B3 hyperimmune monkey serum eventually eliminated virus from carrier cultures indicating that a lysogenic virus-cell relationship was not operative. Free virus was produced continuously by carrier cultures despite washing and neutralization with antiserum to eliminate free virus temporarily. In carrier cultures, about 1.5 to 1.9 plaque-forming units of virus per cell were cell-associated; approximately 6 per cent of this cell-associated virus was not neutralizable by antiserum. In growth medium containing anti-B3 antibody, cells from carrier cultures formed colonies as efficiently as cells from B3-cured cultures. Assays of carrier cultures for infectious centers indicated that less than 1 per cent of cells produced free infectious virus. The Coxsackie B3 virus-carrier state appeared to represent surface residence of B3 virus on the majority of carrier cells with restriction of productive infection to a small proportion of the population. Coxsackie B3 carrier HeLa cultures, unlike control cultures, were not destroyed by challenge with Coxsackie B1, B3, or B5 viruses. The B3 carrier state did not interfere with superinfection by herpes, vaccinia, and types 1 to 3 polioviruses. In contrast to parental or B3-cured lines, B3-carrier HeLa cultures superinfected with Coxsackie B1 virus produced no significant virus, and cultures superinfected with B5 viruses produced new virus to a limited extent only. Specific interference with Coxsackie virus superinfection by the B3-carrier state of HeLa cells was shown to be attributable to failure of attachment in the instance of Coxsackie B1 virus, and failure of penetration and/or eclipse in the instance of B5 virus. The interfering effect was circumvented successfully by superinfection of carrier cells with ribonucleic acid extracted from Coxsackie B1 and B5 viruses.