Association of neutralization sensitivity of HIV-1 primary isolates with biological properties of isolates from HIV-1 infected Chinese individuals.
OBJECTIVE
Although HIV-1 infection is prevalent in many regions in China, it remains largely unknown on the biological characteristics of dominant circulating isolates. This study was designed to isolate the circulating viral strains from different prevalent regions and to characterize their biological properties and neutralization sensitivity.


METHODS
Primary viruses were isolated from fresh PBMCs using the traditional co-culture method and their capacity of inducing syncytium was tested in MT-2 cells. Meanwhile, their coreceptor usage was determined with two cell lines: Magi and GHOST (3) stably expressing CD4 and the chemokine receptor CCR5 or CXCR4. Furthermore, the sensitivity of these viruses to neutralization by HIV-1-infected patients' plasma which were highly active to neutralize SF33 strain, was quantified in GHOST cell-based neutralization assay.


RESULTS
Six primary viral strains were isolated from 4 separated regions. Isolates LTG0213, LTG0214 and XVS032691 induced syncytia in MT-2 cells, and used CXCR4 as coreceptor. Isolates XJN0021, XJN0091, or SHXDC0041 did not induce syncytia, and used CCR5 as coreceptor. Overall neutralization sensitivity differed among four representative strains: HIV-1 XVS032691 > LTG0214 >XJN0091 approximately SHXDC0041.


CONCLUSIONS
The neutralization sensitivity of HIV isolates is linked with the phenotype of isolates, in which syncytium-inducing (SI) or CXCR4-tropic (X4) viruses are more easily neutralized than non-syncytium-inducing (NSI) or CCR5-tropic (R5) viruses. The genetic subtypes based on the phylogeny of env sequences are not classical neutralization serotypes.
Hei
Fa-Xin
FX
Department of Virology and Immunology, National Center for AIDS/STD Control and Prevention, Chinese Centerfor Disease Control and Prevention, Beijing 100050, China.
Tang
Hai-Li
HL
Hong
Kun-Xue
KX
Chen
Jian-Ping
JP
Peng
Hong
H
Yuan
Lin
L
Xu
Jiang-Qing
JQ
Shao
Yi-Ming
YM
D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D018925:Chemokines / Q000235:genetics / Q000276:immunology; D002681:China; D018920:Coculture Techniques / Q000379:methods; D015726:Giant Cells / Q000648:ultrastructure / Q000821:virology*; D015658:HIV Infections / Q000821:virology*; D006679:HIV Seropositivity / Q000235:genetics / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology / Q000302:isolation & purification* / Q000502:physiology; D006801:Humans; D009500:Neutralization Tests; D019713:Receptors, CCR5 / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism; D014779:Virus Replication
D018925:Chemokines; D019713:Receptors, CCR5; D019718:Receptors, CXCR4