Laboratory characteristics of an attenuated influenza type A (H3N2) virus (‘Alice’ strain)

Abstract

SUMMARYThe Alice strain of live attenuated influenza virus was obtained by selection of a y inhibitor-resistant strain from a virus recombinant between A/PR/8/34 (HON1) and A/England/42/72 (H3N2). Its behaviour in vitro and in vivo was studied. Three marker systems were investigated: resistance to serum inhibitors, growth capacity at high temperature and low sensitivity to amantadine hydrochloride. In ferrets the strain was found to be attenuated and immunogenic. Passages in man, animals and eggs have not affected its resistance to y inhibitors.

Influenza virus infection of newborn rats: Virulence of recombinant strains prepared from a cold-adapted, attenuated parent

“…MAHMUD, H. F. MAASSAB, 1~. JENNINGS, and C. W. POTTER: in ferret and human organ cultures (13,14), virus replication in ferrets (4,7,23) and growth in hamsters (16) have been investigated as possible methods of assessing virus virulence for man: the tests using animal models require confirmation and extension to recombinant viruses produced by a variety of methods before an assessment of reliability can be made, whilst the effects of virus growth in organ cultures has been shown to correlate with human virulence for some influenza virus strains, but not for others (6).…”

Influenza A Virus Neuraminidase Limits Viral Superinfection

“…Influenza A viruses A/PR/8/34 (H1N1) and Alice strain (H3N2) were purchased from the ATCC. Alice strain is a recombinant between A/PR/8/34 and A/England/42/72 (H3N2), with HA and NA segments derived from the latter strain (23). Various recombinant A/PR/8/34 (H1N1) and A/Udorn/72 (H3N2) viruses, carrying different combinations of an amantadineresistant/sensitive M segment and an oseltamivir-resistant/sensitive NA segment, were generated following a previously described method (8).…”

Influenza virus infection of newborn rats: virulence of recombinant strains prepared from influenza virus strain A/Okuda/57

“…Considerable advantage could be obtained from the successful development of a laboratory technique for measuring virulence for man; to this end, the replication of virus in ferrets (Lobmann et al ., 1976;Toms et al, 1976;Fenton, Jennings and Potter, 1977), virus replication in hamsters (Murphy et al, 1972) and growth in organ cultures of human ferret trachea Tyrrell, 1972, 1973) have been investigated as possible models. At present none of these techniques is a satisfactory alternative to volunteer studies; correlation of the results of human studies with those in tissue culture have been poor (Hara, Beare and Tyrrell, 1974), whilst too few strains have been studied in animals to allow conclusions.…”