RESUMO
Primary effusion lymphoma (PEL) is a B cell lymphoma that is always associated with Kaposi's sarcoma-associated herpesvirus (KSHV) and in many cases also with Epstein-Barr virus (EBV); however, the requirement for EBV coinfection is not clear. Here, we demonstrate that adding exogenous EBV to KSHV+ single-positive PEL leads to increased KSHV genome maintenance and KSHV latency-associated nuclear antigen (LANA) expression. To show that EBV was necessary for naturally coinfected PEL, we nucleofected KSHV+/EBV+ PEL cell lines with an EBV-specific CRISPR/Cas9 plasmid to delete EBV and observed a dramatic decrease in cell viability, KSHV genome copy number, and LANA expression. This phenotype was reversed by expressing Epstein-Barr nuclear antigen 1 (EBNA-1) in trans, even though EBNA-1 and LANA do not colocalize in infected cells. This work reveals that EBV EBNA-1 plays an essential role in the pathogenesis of PEL by increasing KSHV viral load and LANA expression.
Assuntos
Herpesvirus Humano 4/fisiologia , Herpesvirus Humano 8/genética , Linfoma de Efusão Primária/virologia , Sarcoma de Kaposi/virologia , Antígenos Virais/genética , Antígenos Virais/metabolismo , Linhagem Celular , Coinfecção/virologia , Antígenos Nucleares do Vírus Epstein-Barr/genética , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Regulação Viral da Expressão Gênica , Genoma Viral , Herpesvirus Humano 4/genética , Herpesvirus Humano 8/metabolismo , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismoRESUMO
Kaposi's sarcoma-associated herpesvirus (KSHV) induces B cell hyperplasia and neoplasia, such as multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL). To explore KSHV-induced B cell reprogramming in vivo, we expressed the KSHV latency locus, inclusive of all viral microRNAs (miRNAs), in B cells of transgenic mice in the absence of the inhibitory FcγRIIB receptor. The BALB/c strain was chosen as this is the preferred model to study B cell differentiation. The mice developed hyperglobulinemia, plasmacytosis, and B lymphoid hyperplasia. This phenotype was ameliorated by everolimus, which is a rapamycin derivative used for the treatment of mantle cell lymphoma. KSHV latency mice exhibited hyperresponsiveness to the T-dependent (TD) antigen mimic anti-CD40 and increased incidence of pristane-induced inflammation. Lastly, the adaptive immunity against a secondary infection with Zika virus (ZIKV) was markedly enhanced. These phenotypes are consistent with KSHV lowering the activation threshold of latently infected B cells, which may be beneficial in areas of endemicity, where KSHV is acquired in childhood and infections are common.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) establishes latency in B cells and is stringently linked to primary effusion lymphoma (PEL) and the premalignant B cell hyperplasia multicentric Castleman's disease (MCD). To investigate potential genetic background effects, we expressed the KSHV miRNAs in BALB/c transgenic mice. BALB/c mice are the preferred strain for B cell hybridoma development because of their propensity to develop predictable B cell responses to antigen. The BALB/c latency mice exhibited a higher incidence of B cell hyperplasia as well as sustained hyperglobulinemia. The development of neutralizing antibodies against ZIKV was augmented in BALB/c latency mice. Hyperglobulinemia was dampened by everolimus, a derivative of rapamycin, suggesting a role for mTOR inhibitors in managing immune activation, which is hallmark of KSHV infection as well as HIV infection.
Assuntos
Linfócitos B/virologia , Resistência à Doença/genética , Herpesvirus Humano 8/imunologia , Receptores de IgG/imunologia , Sarcoma de Kaposi/imunologia , Latência Viral , Infecção por Zika virus/imunologia , Animais , Antineoplásicos/farmacologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Diferenciação Celular/efeitos dos fármacos , Coinfecção , Everolimo/farmacologia , Herpesvirus Humano 8/efeitos dos fármacos , Herpesvirus Humano 8/genética , Humanos , Hipergamaglobulinemia/genética , Hipergamaglobulinemia/imunologia , Hipergamaglobulinemia/virologia , Imunossupressores/farmacologia , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Nus , MicroRNAs/genética , MicroRNAs/imunologia , Plasmocitoma/genética , Plasmocitoma/imunologia , Plasmocitoma/virologia , RNA Viral/genética , RNA Viral/imunologia , Receptores de IgG/deficiência , Receptores de IgG/genética , Sarcoma de Kaposi/genética , Sarcoma de Kaposi/virologia , Terpenos/farmacologia , Zika virus/efeitos dos fármacos , Zika virus/genética , Zika virus/imunologia , Infecção por Zika virus/genética , Infecção por Zika virus/virologiaRESUMO
Interleukin 6 (IL-6) is considered a proliferation and survival factor for B cells. To assess the role of IL-6 in Kaposi sarcoma-associated herpesvirus (KSHV) latency, KSHV latency locus-transgenic mice (referred to as latency mice) lacking IL-6 were evaluated. IL-6(-/-) latency mice had the same phenotypes as the latency mice, i.e., increased frequency of marginal zone B cells, hyperplasia, and hyperglobulinemia, indicating that the KSHV latency locus, which includes all viral microRNAs (miRNAs), can compensate for lack of IL-6 in premalignant B cell activation.