Figure 3
Retrovirus-induced syncytia formation, proviral DNA detection and RT assay. a) Syncytia formation of HIV/SIV as a sign of acute infection was manifested by nuclear aggregation in multinucleated giant cells (MGC) detected by Giemsa staining. Both HIV-2MIR and SIVsmE660 induced syncytia formation in NP-2/CD4/CKR-L3 and NP-2/CD4/CCR6 cells. However, syncytia formation in the former cell line was shorter than the latter for both viral variants. b) As evidence of retroviral DNA integration into the host cell genome, proviral DNA was detected by PCR using the genomic DNA of the infected NP-2/CD4/CKR-L3 and NP-2/CD4/CCR6 cells as templates. c) Reverse transcriptase (RT) assay was done to detect HIV-2MIR replication efficiency using CKR-L3 and CCR6 as coreceptors. Culture supernatants of infected cells were harvested at different time points of infection-cycle. Mean cpm values of the duplicate samples were determined. CKR-L3 mediated increased and more rapid RT release than that of CCR6.