Jpn. J. Infect. Dis., 53, 2000

Laboratory and Epidemiology Communications

Confined Replication of a Chimeric Simian ImmunodeflCiency Virus
Akiko Takeda, Hiromi Nakamura and Tetsuro Matano*
AIDS Resewch Center: National Institute of Infectious Diseases,
Gakuen 4‑ 7‑I, Musashi‑murayama, Too)0 208‑0011
Communicated by Hiroshi Yoshikura(Accepted November 2, 2000)

We generated a chimeric SIV, FMSIV, by replacing SIV env
with ecotropic Friend murine leukemia virus (FMLV) env toDuring the acute phase of infection with lentiviruSes suchas human immunodeficiency virus type 1 (HIV‑1) and simian
immunodeflCiency.virus (SIV), virus‑specific cellular immune

responses playanlmPOrtant role in controllingvirus replica‑

Ponfine its replication to FMLV receptor (mCAT 1 )‑express‑
lng Cells. In prlmate Cells lacking mCATl, FMSIV did nottion (1‑3)･ DNA vaccine is a prワmising candidate fわr AIDS

replicate unless mCATI was introduced exogenously. Vaccina‑

vaccine strategies tO induce the virus‑SPeCifiC cellular immune

tion to macaqueswith both the FMSIV DNA andthe mCATl ‑responses efrlCiently. Conventional DNA vaccine strategies,

expression plasmid DNA induced mCAT 1 ‑dependent FMSIV

however, have failed to prevent the onset of disease (4).

replication. This strategy elicited SIV‑Specific cellular immune

We previously reported a novel DNA vaccine strategy toresponses and resistance agalhst pathogenic SIVmac239 chal‑

induce safer, restricted replication of an avirulent virus (5).

lenge more emciently than did a conventional replication‑negative DNA vaccine. mCATl ‑dependent FMSIV replica‑tion would be safer than hve attenuatedvirus replication. In*Corresponding author: Fax: +8 1 ‑42‑565‑33 1 5･ E‑mail: matano@our previous in vitro study, SIV Gag p27 production innih.goJp209

Jpn. J. 1nfect. Dis., 53, 2000
supernatant was observed not in the mock‑transfected but inantibody (Cappel, Aurora, Ohio, USA) as previ?usly

the mCATI DNA‑transfected COS cells after FMSIV infec‑

described (8). The mock‑transfected COS cells were resIStanttion, indicatlng the occu汀enCe OrmCATトdependent FMSIVto FMSIV infection (Fig. lB), whereas the pmCAT1‑GFP‑
transfected COS cells were.se.nsitive to FMSIV infection (Fig･1C). The p27‑positive stalnlng Was localized within GFP‑

replication. This study was undertaken in order to confirm

that the FMSIV replication was confined within the mCATl ‑expresslng CeHs･positive cells (Fig. lC), indicating that FMSIV could infectonly the cells expresslng the FMLV receptor.
The above results confirmed that the FMSIV infection was

For preparation ofviral supernatants, COS cells were trans‑

fected with SHIV‑MD14YE (6) Or FMSIV DNA. Two days

0.45lLLm‑pore‑Size filter to obtain the SHIV or FMSJV viralconfined within the mCAT1‑expresslng Cells. Thus, Ourstrategy may be useful for development ofa safe and effective

supernatant. For infection, COS cells were plated at a density

AIDS vaccine, although its potential risk requlreS凡Irtherof2 × 105 per well in 6‑weH plates, incubated ovemight, andevaluation.

later, the supernatants were harvested and rlltered through atransfected with 2 LLg of mock plasmid vector (PCMVN [5])or 2 LLg ofpmCATl‑GFP, a pIasmid vector expresslng

We thank M. A. Martin fわr providing SHIV‑MD14YEmCATl‑GFP rusjon protein (7). The mCATl‑GFP wasDNA, M. Masuda fわr providing pmCATトGFP DNA, and T.

previously shown to work as an FMLV receptor. One day

Sata fわr providing the anti‑p27 antibody. This work wasafter the transfection, the cells were cultured with the SHIV
or FMSIV viral supematant. The dose orthe supematant usedsupported by a grant forAIDS Research from the Ministry ofHealth and Welfare in Japan.

for each infection contained 1 0 ng/ml ofp27. Two days afterthe infection, ceHs were rlXed, permeabilized, and immuno‑REFERENCES

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Fig. 1. Immunonuorescent analysis. Leftpanels show GFP expression
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