Infection of primary CD4+ and CD8+ T lymphocytes by Epstein-Barr virus enhances human immunodeficiency virus expression

Carcinogenic mechanisms of virus-associated lymphoma

The development of lymphoma is a complex multistep process that integrates numerous experimental findings and clinical data that have not yet yielded a definitive explanation. Studies of oncogenic viruses can help to deepen insight into the pathogenesis of lymphoma, and identifying associations between lymphoma and viruses that are established and unidentified should lead to cellular and pharmacologically targeted antiviral strategies for treating malignant lymphoma. This review focuses on the pathogenesis of lymphomas associated with hepatitis B and C, Epstein-Barr, and human immunodeficiency viruses as well as Kaposi sarcoma-associated herpesvirus to clarify the current status of basic information and recent advances in the development of virus-associated lymphomas.

Leishmania donovani and HIV co-infection in vitro: Identification and characterization of main molecular players

The incidence of Leishmania/HIV co-infection is growing and few studies detail the cellular processes and macromolecules participating in co-infection. Thus, the goal of this study was to partially describe the Leishmania/HIV co-infection events by measuring molecular and functional parameters associated with both pathogens in vitro. MT-4 cells (human T-lymphocytes), primary monocytes, and peripheral blood mononuclear cells were exposed to HIV and/or Leishmania donovani. The cytopathic effects generated by the pathogens were observed through microscopy. Viral replication was assessed by monitoring p24 protein levels and parasitic proliferation/infectivity was determined using Giemsa staining. Changes in molecular markers were evaluated by ELISA and fluorescence assays. Our results showed that our system reassembles the main parameters previously described for Leishmania/HIV co-infection in patients in terms of potentiation of parasitic and viral replication/infectivity, amplification of syncytia induction, and alterations of cell viability. In addition, an amplification in NF-κB activation, changes in CXCR4/CCR5 surface expression, and a Th1→Th2 variation in cytokine/chemokine secretion were demonstrated. Altogether, this study could contribute to gain a deep understanding of the molecular events associated with Leishmania/HIV co-infection.

The Role of Coinfections in the EBV-Host Broken Equilibrium

The Epstein–Barr virus (EBV) is a well-adapted human virus, and its infection is exclusive to our species, generally beginning in the childhood and then persisting throughout the life of most of the affected adults. Although this infection generally remains asymptomatic, EBV can trigger life-threatening conditions under unclear circumstances. The EBV lifecycle is characterized by interactions with other viruses or bacteria, which increases the probability of awakening its pathobiont capacity. For instance, EBV infects B cells with the potential to alter the germinal center reaction (GCR)—an adaptive immune structure wherein mutagenic-driven processes take place. HIV- and Plasmodium falciparum-induced B cell hyperactivation also feeds the GCR. These agents, along with the B cell tropic KSHV, converge in the ontogeny of germinal center (GC) or post-GC lymphomas. EBV oral transmission facilitates interactions with local bacteria and HPV, thereby increasing the risk of periodontal diseases and head and neck carcinomas. It is less clear as to how EBV is localized in the stomach, but together with Helicobacter pylori, they are known to be responsible for gastric cancer. Perhaps this mechanism is reminiscent of the local inflammation that attracts different herpesviruses and enhances graft damage and chances of rejection in transplanted patients. In this review, we discussed the existing evidence suggestive of EBV possessing the potential to synergize or cooperate with these agents to trigger or worsen the disease.

Lytic replication of Epstein-Barr virus in human peripheral T-lymphocytes

Background: There are few reports about the interactions of EBV with peripheral T-cells, especially during the early phase of infection. Objective: Demonstrate the capability of EBV to infect and replicate in human peripheral T-cells in vitro. Methods: After treating with EBV, the susceptibility of in vitro EBV infection into T-cells was confirmed using electron microscopy, the expression of EBV mRNA using RT-PCR, and the expression of EBV proteins using Western blot analysis. The expression of CD19 and CD21 mRNA was determined using RT-PCR. The induction of cell death was measured using trypan blue exclusion assay. Results: The susceptibility of in vitro EBV infection was confirmed by the presence of virus particles in the cytoplasm. The entering to lytic infection was confirmed by detection the expression of EBV lytic (BZLF1) mRNA, and the expression of late lytic proteins (VCA and gp350/220). The expression of CD19 and CD21 were not observed using RT-PCR. The interactions of EBV with T-cells leaded to induction of T-cell death. Conclusion: Peripheral T-cells are a direct target of EBV infection. At the beginning of infection by EBV, EBV infection of T-cells leads to the entering into lytic virus replication. EBV binds to these cells through a receptor distinct from the CD21.

Comparison of the effect of semen from HIV-infected and uninfected men on CD4+ T-cell infection

Objectives:

Semen composition is influenced by HIV-1 infection, yet the impact of semen components on HIV infection of primary target cells has only been studied in samples from HIV-uninfected donors.

Design:

We compared the effect of seminal plasma (SP) from chronically HIV-infected (SP+) versus uninfected donors (SP–) on HIV-1 infection of peripheral blood mononuclear cells (PBMCs) and CD4⁺ T cells.

Methods:

Primary cells were infected with HIV-1 in the presence of SP+ or SP– and analyzed for infection level, metabolic activity, HIV receptor expression, proliferation and activation. SP+ and SP– were compared for infection-enhancing peptides, cytokines and prostaglandin E2 levels.

Results:

SP– efficiently enhanced HIV-1 R5 infection of CD4⁺ T cells, whereas SP+ enhancing activity was significantly reduced. RANTES (CCL5) concentrations were elevated in SP+ relative to SP–, whereas the concentrations of infectivity-enhancing peptides [semen-derived enhancer of viral infection (SEVI), SEM1, SEM2] were similar. CCR5 membrane expression levels were reduced on CD4⁺ T cells shortly postexposure to SP+ compared with SP– and correlated to R5-tropic HIV-1 infection levels, and CCR5 ligands’ concentrations in semen. SP+ and SP– displayed similar enhancing activity on PBMC infection by X4-tropic HIV-1. Addition/depletion of RANTES (regulated on activation, normal T-cell expressed and secreted) from SPs modulated their effect on PBMC infection by R5-tropic HIV-1.

Conclusion:

Semen from HIV-infected donors exhibits a significantly reduced enhancing potential on CD4⁺ T-cell infection by R5-tropic HIV-1 when compared with semen from uninfected donors. Our data indicate that elevated seminal concentrations of RANTES in HIV-infected men can influence the ability of semen to enhance infection.

Cytomegalovirus, and possibly Epstein-Barr virus, shedding in breast milk is associated with HIV-1 transmission by breastfeeding

OBJECTIVE

Postnatal HIV-1 mother-to-child transmission (MTCT) occurs in spite of antiretroviral therapy. Co-infections in breast milk with cytomegalovirus (CMV) and Epstein-Barr virus (EBV) are associated with increased HIV-1 shedding in this compartment. We investigated CMV levels and EBV detection in breast milk as potential risk factors for MTCT of HIV-1 via breastfeeding.

METHODS

Cell-free HIV-1 RNA, cell-associated HIV-1 DNA, CMV and EBV DNA were quantified in breast milk from 62 HIV-infected mothers and proven postnatal MTCT of HIV-1 via breastfeeding. Controls were 62 HIV-positive mothers with HIV-uninfected infants.

RESULTS

Median (interquartile range) CMV DNA viral load was significantly higher in cases [88,044 (18,586-233,904)] than in controls [11,167 (3221-31,152)] copies/10 breast milk cells (P < 0.001). Breast milk CMV DNA level correlated positively with breast milk HIV-1 RNA level in cases and controls. EBV DNA was detectable in a higher proportion of breast milk samples of cases (37.1%) than controls (16.1%; P = 0.009). HIV-1 MTCT was strongly associated with HIV-1 RNA shedding in breast milk and plasma. In multivariable analysis, every 1 log10 increase in breast milk CMV DNA was associated with a significant 2.5-fold greater odds of MTCT of HIV-1, independent of breast milk and plasma HIV-1 levels; the nearly three-fold increased risk of HIV-1 MTCT with breast milk EBV DNA detection did not reach significance.

CONCLUSION

We provide the first evidence of an independent association between CMV in breast milk, and postnatal MTCT of HIV-1. This association could fuel persistent shedding of HIV-1 in breast milk in women receiving antiretroviral therapy. EBV DNA detection in breast milk may also be associated with MTCT of HIV-1, but only marginally so.

Viral DNA contamination is responsible for Epstein-Barr virus detection in cytotoxic T lymphocytes stimulated in vitro with Epstein-Barr virus B-lymphoblastoid cell line

Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell lines (LCLs) are used to prepare human EBV-specific T lymphocytes (EBV-CTL) in vitro. Within an LCL, up to 5-7% the cells release infectious EBV, and this has fostered safety concerns for therapeutic applications because of the exposure of T cells to EBV. The release of infectious viruses can be prevented by ganciclovir, but this drug may seriously affect LCL growth. In the wake of these concerns, the present work was designed to compile safety data on EBV-CTL preparation for the purpose of submission to a regulatory agency. We showed that further to supernatant exclusion, the number of EBV genome copies (EBVc) associated with the EBV-CTL always made up a constant proportion of the EBVc number detected in the culture supernatant. In addition, such was the case whether infectious virus could be produced by the LCL or not, suggesting that the EBV signal detected was due to a DNA contamination rather than an infection. Furthermore, we demonstrated that the number of EBVc associated with the EBV-CTL was highly sensitive to DNAse treatment, and finally that EBVc could no longer be detected after the EBV-CTL had been amplified in the absence of LCL. Consequently, during in vitro EBV-CTL preparation, either T cells cannot be infected or they die rapidly after EBV infection.

Cytokine induction after Epstein-Barr virus infection of peripheral T-lymphocytes in vitro

Background: Although the presence of Epstein-Barr virus (EBV) in different T-cell malignancies has been widely reported, there is very few data available for EBV infection of normal T cells. This leads to the lack of knowledge on the early events after T cell infection. Objective: Investigate the early events occurring after normal human peripheral T-cells are infected with EBV in vitro. Methods: T-cells were treated with EBV in vitro. The expression of tumor necrosis factor- α (TNF-α) mRNA were determined using reverse-transcription (RT)-PCR, and the level of TNF-α and interferon- γ (IFN-γ) in the culture supernatant were measured using ELISA. The effect of virus inactivation on cytokine induction from T-cells was also determined. Results: At the beginning of T cell infection by EBV, the expression of several lytic EBV transcripts (BALF5, BcLF1, and BLLF1) were observed using RT-PCR. This indicated the susceptibility of in vitro EBV infection and the entering lytic cycle of EBV-infected T-cells. The interactions of EBV with T-cells lead to induction of inflammatory cytokines, tumour necrosis factor- α (TNF-α) and interferon- γ (IFN-γ), production from the T-cells. Inactivation of the virus by UV irradiation eliminated the TNF-α and IFN-γ induction by EBV, suggesting the involvement in the expression of viral gene(s). Conclusion: This in vitro analysis demonstrated the cytokine induction by EBV after primary infection of T-cells.

Distribution and phenotype of Epstein-Barr virus-infected cells in human pharyngeal tonsils

Although Epstein-Barr virus (EBV) is often found in human tonsils, it remains to be precisely determined in what cells and microenvironment the virus is present. Although generally regarded as a B lymphotropic virus, EBV is associated with non-B-cell tumors, for example, NK/T-cell lymphoma, carcinoma, and leiomyosarcoma. To provide a basis for understanding the origin and biology of EBV-infected non-B cells, the immunophenotype of all EBV-infected cells in reactive human tonsils was determined by subjecting tonsil sections to dual/triple EBER in situ hybridization and immunohistochemistry with monoclonal antibodies to T cells (CD3, CD4, CD8, CCR3), B cells (CD20), plasma cells (CD138), natural killer (NK) cells (PEN5), and epithelial cells (cytokeratin), as well as frozen section immunostaining with antibodies to EBV latent proteins EBNA1, EBNA2, LMP1, and EBV early protein BZLF1. Most tonsils contained nearly equal numbers of EBNA1- and LMP1-positive cells (latency program) while only a few contained EBNA2-positive cells (growth program). More than 1000 EBER-positive cells from six tonsils were detected in the interfollicular zone (59%), tonsillar crypts (26%), and follicles (15%). Most (82%) EBER-positive cells are CD20-positive B cells, 7% are CD3-positive T cells, and 11% are cells of indeterminate lineage, often with plasmacytoid morphology. However, no EBER-positive plasma cells were identified. Rare EBER-positive NK cells and EBER/BZLF1-positive epithelial cells were identified. The direct demonstration of EBV within rare T cells, NK cells, and epithelial cells in reactive human tonsils provide a basis for further understanding of the origin of EBV-associated tumors of non-B-cell type.

Interactions between human immunodeficiency virus and herpes viruses within the oral mucosa

There is evidence from clinical case reports and epidemiological studies that human immunodeficiency virus (HIV) can be transmitted through oral sex. Herpes viruses that appear in the oral mucosa might influence the oral replication of HIV. A review of data suggesting that interactions occur between HIV and herpes viruses indicates that such interactions might operate in the oral mucosa. Defining the mechanisms by which herpes viruses interact with HIV in the oral mucosa should permit intervention measures to be targeted more precisely.

Epstein-Barr Virus Infection of Human Natural Killer Cell Lines and Peripheral Blood Natural Killer Cells

Although considerable part of natural killer (NK) cell neoplasms possess EBV genome, there has been no direct evidence that EBV infects human NK cells in vitro. In this study, we demonstrated EBV entry into NK cells using a recombinant EBV, which contains enhanced green fluorescent protein (EGFP) gene in its genome (EGFP-EBV). After 48 h of exposure to EGFP-EBV, we detected EGFP signals in ∼30% of NK-92 and NKL cells and &gt;40% of peripheral blood NK cells from three healthy volunteers. Reverse transcription-PCR analysis of various EBV-associated genes confirmed EBV infection. In situ hybridization for EBERs and BHLFs showed that latent and lytic infections coexisted at the early phase of EBV infection in two NK cell lines. Although BHLF-positive cells in the early lytic phase were round-shaped, EBER-positive cells in latent EBV infection tended to show a bizarre shape. Flow cytometric analysis of EGFP-EBV-exposed NK cell lines showed that most of EBV-infected cells entered early apoptosis after 72 h of EBV exposure, which explains the difficulties to establish EBV-carrying NK clones. Flow cytometry and reverse transcription-PCR analysis indicated that two NK cell lines may fuse with EBV using HLA class II after binding to the virus through a distinct molecule from CD21. We established two EBV-carrying NKL clones showing latency types I and II, both of which are recognized in EBV-associated NK cell neoplasms. Because EBV-infected NKL cells showed only type I latency during the early phase of infection, the temporal profile of latent gene expression is similar to that of T cells. We first report in vitro EBV infection of human NK cells and establishment of EBV-carrying NK clones, which should contribute to elucidate the role of EBV in the development of NK cell neoplasms.

Hepatitis C virus-Epstein-Barr virus interaction in patients with AIDS

Immortalization of B cells by Epstein-Barr virus (EBV) and their subsequent proliferation leads to B-cell non-Hodgkin's lymphoma in immunocompromised patients. The role of hepatitis C virus (HCV) in B-cell non-Hodgkin's lymphoma has recently been raised, and an interaction between HCV and EBV is supported by recent in vitro experiments. The aim of this study was to investigate in vivo interactions between HCV and EBV in patients with AIDS, i.e., patients exposed to the risk of EBV-related B-cell non-Hodgkin's lymphoma. A total of 135 patients were prospectively studied. Serological and molecular markers of HCV, EBV, and human immunodeficiency virus (HIV) infection were sought. All the patients harbored latent EBV infection, and 20% had detectable HCV RNA in serum. No significant relationship was found between HIV, HCV, and EBV viral load in peripheral blood mononuclear cells or plasma. There was no difference between anti-HCV-positive and -negative patients or between HCV RNA-positive and -negative patients with regard to the prevalence of EBV markers, especially EBV replication markers. The presence of EBV replication markers was not related to HCV RNA seropositivity or to HCV viral load. Five patients subsequently developed B-cell non-Hodgkin's lymphoma, none of whom had markers of EBV or HCV replication. These results argue against an in vivo interaction between HCV and EBV in patients with AIDS, and against a role of HCV infection in the occurrence of B-cell non-Hodgkin's lymphoma in these patients.

Synergism between HIV and other viruses in the mouth

The HIV family replicate in and are shed from the mouth. Oral sexual practices potentially contribute to the overall extent of HIV transmission, particularly if high-risk practices are not restricted. Herpesviruses and papillomaviruses that appear in the oral cavity can determine oral HIV replication. The mechanisms probably include heterologous transactivation, enhanced expression of HIV receptors and co-receptors in target cells, release of cytokines and chemokines, and production of superantigens. Oral diseases peculiar to, or more common in, the HIV-infected patient further predispose to heightened oral HIV replication and trafficking. Defining the mechanisms by which oral viruses interact with HIV in the co-infected host should permit intervention measures against oral HIV transmission to be more precisely targeted.

Reciprocal regulatory interaction between human herpesvirus 8 and human immunodeficiency virus type 1

Human herpesvirus 8 (HHV8) is the primary viral etiologic agent in Kaposi's sarcoma (KS). However, individuals dually infected with both HHV8 and human immunodeficiency virus type 1 (HIV-1) show an enhanced prevalence of KS when compared with those singularly infected with HHV8. Host immune suppression conferred by HIV infection cannot wholly explain this increased presentation of KS. To better understand how HHV8 and HIV-1 might interact directly in the pathogenesis of KS, we queried for potential regulatory interactions between the two viruses. Here, we report that HHV8 and HIV-1 reciprocally up-regulate the gene expression of each other. We found that the KIE2 immediate-early gene product of HHV8 interacted synergistically with Tat in activating expression from the HIV-1 long terminal repeat. On the other hand, HIV-1 encoded Tat and Vpr proteins increased intracellular HHV8-specific expression. These results provide molecular insights correlating coinfection with HHV8 and HIV-1 with an unusually high incidence of KS.

Stable expression of Epstein-Barr virus BZLF-1–encoded ZEBRA protein activates p53-dependent transcription in human Jurkat T-lymphoblastoid cells

Interaction between viral proteins and tumor suppressor p53 is a common mechanism of viral pathogenesis. The Epstein-Barr virus (EBV) BZLF-1 ORF-encoded ZEBRA protein (also denoted EB1, Z, Zta) binds to p53 in vitro and has been associated with the altered transcription of p53-regulated genes in B lymphocytes and epithelial cells. In this work, Jurkat T-lymphoblastoid cells that express ZEBRA were characterized by the use of transiently transfected p53 and p53 reporter genes. Stable expression of ZEBRA was associated with the activation of p53-dependent transcription and increased p53 dependent apoptotic cell death. In Jurkat cell lines, stably expressed ZEBRA protein was apparently localized to the cell cytoplasm, in contrast to the typical nuclear localization of this protein in other cell types. Previous studies have suggested that EBV infection of T lymphocytes may contribute to the malignant transformation of T cells and the increased replication of human immunodeficiency virus. Our observations suggest a mechanism through which ZEBRA protein expressed in human T lymphocytes could alter T-cell proliferation and apoptosis during EBV infection.

Stable expression of Epstein-Barr virus BZLF-1–encoded ZEBRA protein activates p53-dependent transcription in human Jurkat T-lymphoblastoid cells

Interaction between viral proteins and tumor suppressor p53 is a common mechanism of viral pathogenesis. The Epstein-Barr virus (EBV) BZLF-1 ORF-encoded ZEBRA protein (also denoted EB1, Z, Zta) binds to p53 in vitro and has been associated with the altered transcription of p53-regulated genes in B lymphocytes and epithelial cells. In this work, Jurkat T-lymphoblastoid cells that express ZEBRA were characterized by the use of transiently transfected p53 and p53 reporter genes. Stable expression of ZEBRA was associated with the activation of p53-dependent transcription and increased p53 dependent apoptotic cell death. In Jurkat cell lines, stably expressed ZEBRA protein was apparently localized to the cell cytoplasm, in contrast to the typical nuclear localization of this protein in other cell types. Previous studies have suggested that EBV infection of T lymphocytes may contribute to the malignant transformation of T cells and the increased replication of human immunodeficiency virus. Our observations suggest a mechanism through which ZEBRA protein expressed in human T lymphocytes could alter T-cell proliferation and apoptosis during EBV infection.

Incomplete HIV-1 activation in latently infected U1 cells demonstrated by double in situ hybridization

Triple combination antiretroviral therapy can reduce HIV-1 infection to a relatively small pool of latently infected cells. To eliminate this residual source of virus, new therapies designed to activate latently infected cells are currently being tested. We therefore investigated the kinetics of in vitro HIV-1 RNA induction using chronically infected U1 cells. A new two-probe fluorescence in situ hybridization (double ISH) method was devised to simultaneously assess total HIV-1 RNA (T-RNA) and unspliced HIV-1 RNA (U-RNA) expression in individual cells. Activation of the U1 cells resulted in increasing expression of T-RNA between 0 and 24 h with lagging expression of U-RNA between 6 and 30 h. Both the positive area per cell and the number of positive cells increased with time. Although activation induced 98.5% of the cells to express HIV-1 T-RNA by 24 h, 52% remained negative for U-RNA. In contrast, 100% of 8E5 cells, which constitutively express HIV-1, scored positive for U-RNA as well as T-RNA with the double ISH. This study provides, for the first time, a semiquantitative cell-by-cell analysis of HIV-1 mRNA subsets in latently infected cells. Our results establish the advantages of using double fluorescence ISH to study gene expression and demonstrate that chronically infected U1 cells remain in a partially induced state despite potent activation.

Inactivation of NF-κB by EBV BZLF-1-Encoded ZEBRA Protein in Human T Cells

We have previously shown that the EBV ZEBRA protein (also denoted EB1, Z, or Zta) encoded by the BZLF open reading frame is expressed in primary human thymocytes and in human T lymphoblastoid cell lines infected by EBV. Expression of EBV-encoded gene products in T lymphocytes could contribute to viral pathogenesis during acute EBV infection as well as in individuals coinfected with EBV and HIV. HPB-ALL and Jurkat T lymphoblastoid cell lines transiently and stably expressing ZEBRA were characterized in this work. Expression of ZEBRA protein in human T lymphoblastoid cells was associated with decreased expression of an NF-κB reporter gene, altered expression of the NF-κB p50 protein subunit, and decreased DNA binding by components of NF-κB. These observations suggest that inactivation of NF-κB transcription by ZEBRA in EBV-infected T cells may be a novel mechanism of viral pathogenesis analogous in part to over-expression of the endogenous cytoplasmic inhibitor of NF-κB, IκBα.

Strong response of T cells in infants with dual infection by Epstein-Barr virus and cytomegalovirus

BACKGROUND

Although a reversed CD4/CD8 ratio and increased proportion of CD8+ HLA-DR+ T cells are well known as the characteristic immune response in infectious mononucleosis (IM), it has not been elucidated whether these immune responses are affected by patient age and pathogenetic viruses.

METHODS

T cell subsets were analyzed by two-color flow cytometry using fluorescein isothiocyanate- and phycoerythrin-conjugated monoclonal antibodies in 115 infants and children aged from 4 months to 10 years with IM due to Epstein-Barr virus (EBV), cytomegalovirus (CMV) and dual infection with both viruses.

RESULTS

A reversed CD4/CD8 ratio and increased proportions of CD4+/HLA-DR+ T cells, CD8+ T cells and CD8+/HLA-DR+ T cells became more prominent as the age of the patients became older. No differences were observed in proportions of T cell subsets between EBV- and CMV-infection among patients aged from 6 to 17 months. Although the responses of these T cells were weak in infants with single virus infection by EBV and CMV, markedly strong T cell responses comparable with those in older children were observed in infants with EBV/CMV dual infection. Clinical symptoms were more severe in patients with EBV/CMV dual infection than those with EBV or CMV alone.

CONCLUSION

The manner of these T cell responses in the acute phase of IM was considered to be age dependent, although strong T cell responses and severe disease were observed in EBV/CMV dual infection irrespective of patient age.

Maternal and perinatal factors related to maternal-infant transmission of HIV-1 in the P2C2 HIV study: the role of EBV shedding. Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted HIV-1 Infection (P2C2 HIV) Study Group

The association of maternal and perinatal factors with mother-infant transmission of HIV-1 was examined in a prospective multicenter cohort of singleton live births to 508 HIV-1-infected women with children of known HIV-1 infection status (91 [18%] HIV-1-infected, 417 [82%] uninfected). From multivariate logistic regression, independent predictors of HIV-1 transmission included maternal CD4 percentage (CD4%) (odds ratio [OR] per 10% increase in CD4% = 0.70; p = .003), ruptured membranes <24 hours (OR = 3.15; p = .02), and maternal bleeding (OR = 2.90; p = .03), whereas maternal zidovudine (ZDV) use was marginally associated (OR = 0.60; p = .08). The associations of maternal urinary cytomegalovirus (CMV) shedding, oropharyngeal Epstein-Barr virus (EBV) shedding, and serology profiles during pregnancy with HIV-1 transmission were examined in the subset of mothers in whom the CMV and EBV measurements were available. Maternal EBV seropositivity, CMV shedding, and CMV seropositivity were 100% (279 of 279), 7% (16 of 229), and 92% (270 of 274), respectively. These rates did not differ between transmitting and nontransmitting mothers. In univariate analyses, maternal EBV shedding was higher among transmitting than nontransmitting mothers (40 of 49 [82%] compared with 154 of 226 [68%]; p = .06) and was independently associated with transmission in multivariate logistic analyses adjusting for CD4%, ruptured membranes, and ZDV use, with an OR of 2.45 (95% confidence interval (CI), 1.03-5.84; p = .04). This permits the conclusion that EBV shedding is associated with maternal-infant HIV-1 transmission, independent of CD4%.