Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: A persistent infection by human coronavirus 229E (HCV/229E) was established in a human continuous cell line (L 132). Following the initial infection with stock HCV/229E, several cultures were established of which two (HV t and IIV4) have been maintained by continous passage for two years. These eultures have shed high titres of infectious virus continuously into the supernatant fluid since their initiation. The persistently infected ceils were resistant to homologous superinfection but supported polio virus replication to normal titres. Preliminary tests indicated that 50--100 percent of the cells contain virus. Neither interferon nor reverse transeriptase could be detected in these cultures and the presence of defective interfering particles could not be demonstrated. VH t and V H 4 coronaviruses, isolated from these persistently infected cultures (HV) and identified by 229E antiserum neutralization, were more eytoeidal than the parent virus as judged by plaque characteristics and CPE however, they were indistinguishable on the basis of density, EM morphology, a.nd genome size. Present evidence indicates that temperature plays an important but as yet undetermined role in the establishment and maintenance of stable 229 E persistently infected cell cultures. 0304-8608/81/0069/0117/$02.60 6, 128--132 (1975/76).

Archives of Virology Establishment and Maintenance of a Persistent Infection of L 132 Cells by Human Coronavirus Strain 229E