The RBP-Jκ binding sites within the RTA promoter regulate KSHV latent infection and cell proliferation

Kaposi's sarcoma-associated herpesvirus (kshv) is tightly linked to at least two lymphoproliferative disorders,primary effusion lymphoma (pel) and multicentric castleman's disease (mcd). however,the development of kshv-mediated lymphoproliferative disease is not fully understood. here,we generated two recombinant kshv viruses deleted for the first rbp-jκ binding site (rta 1st) and all three rbp-jκ binding sites (rta all) within the rta promoter. our results showed that rta 1st and rta all recombinant viruses possess increased viral latency and a decreased capability for lytic replication in hek 293 cells,enhancing colony formation and proliferation of infected cells. furthermore,recombinant rta 1st and rta all viruses showed greater infectivity in human peripheral blood mononuclear cells (pbmcs) relative to wt kshv. interestingly,kshv bac36 wt,rta 1st and rta all recombinant viruses infected both t and b cells and all three viruses efficiently infected t and b cells in a time-dependent manner early after infection. also,the capability of both rta 1st and rta all recombinant viruses to infect cd19+ b cells was significantly enhanced. surprisingly,rta 1st and rta all recombinant viruses showed greater infectivity for cd3+ t cells up to 7 days. furthermore,studies in telomerase-immortalized human umbilical vein endothelial (tive) cells infected with kshv corroborated our data that rta 1st and rta all recombinant viruses have enhanced ability to persist in latently infected cells with increased proliferation. these recombinant viruses now provide a model to explore early stages of primary infection in human pbmcs and development of kshv-associated lymphoproliferative diseases. © 2012 lu et al.