Prophylaxis against a Melanesian variant of human T-lymphotropic virus type
I (HTLV-I) in rabbits using HTLV-I immune globulin from asymptomatically
infected Japanese carriers
Y Tanaka, K Ishii, T Sawada, Y Ohtsuki, H Hoshino, R Yanagihara and I Miyoshi
Department of Medicine, Kochi Medical School, Japan.
Molecular variants of human T-lymphotropic virus type I (HTLV-I), which
diverge significantly from the so-called cosmopolitan prototypes, have been
discovered in Melanesia. In this study, HTLV-I IgG (I-IgG) prepared from
seropositive healthy Japanese carriers was evaluated for its protective
effect against a Melanesian isolate, HTLV-IMEL5, in rabbits. Normal IgG
(N-IgG) prepared from seronegative healthy Japanese was used as control.
Both preparations contained 50 mg/mL of IgG and I- IgG had a high
neutralizing antibody titer, as determined by vesicular stomatitis
virus--HTLV-I pseudotype assay. Of four experimental groups (A, B, C, and
D), each with three rabbits, groups A and B were infused with 10 mL of
N-IgG and I-IgG, respectively, and animals were challenged immediately by
transfusion of 5 mL of blood from a rabbit infected with HTLV-IMEL5.
Animals in groups C and D were immunized with 10 mL of I-IgG 24 and 48
hours, respectively, after being transfused with 5 mL of blood from the
virus-infected rabbit. HTLV-I infection, as determined by seroconversion
and verified by polymerase chain reaction, occurred in all rabbits in
groups A and D after 2 to 6 weeks, but in none of the animals in groups B
and C. These data indicate that I-IgG is protective against HTLV-IMEL5
infection when administered before or within 24 hours of transfusion with
virus-contaminated blood. Moreover, our study shows that the neutralizing
domains of the so-called cosmopolitan and Melanesian strains of HTLV-I are
functionally indistinguishable.
Volume 82,
Issue 12,
pp. 3664-3667,
12/15/1993
Copyright © 1993 by The American Society of Hematology
