Mechanisms of chronic alcohol exposure-induced aggressiveness in cellular model of HCC and recovery after alcohol withdrawal.

Alcohol-related liver disease is the most prevalent chronic liver disease worldwide, accounting for 30% of hepatocellular carcinoma (HCC) cases and HCC-specific deaths. However, the knowledge on mechanisms by which alcohol consumption leads to cancer progression and its aggressiveness is limited. Better understanding of the clinical features and the mechanisms of alcohol-induced HCC are of critical importance for prevention and the development of novel treatments. Early stage Huh-7 and advanced SNU449 liver cancer cell lines were subjected to chronic alcohol exposure (CAE), at different doses for 6 months followed by 1-month alcohol withdrawal period. ADH activity and ALDH expression were much lower in SNU449 compared with Huh-7 cells and at the 270 mM dose, CAE decreased cell viability by about 50% and 80%, respectively, in Huh-7 and SNU449 cells but induced mortality only in Huh-7 cells. Thus, Huh-7 may be more vulnerable to ethanol toxicity because of the higher levels of acetaldehyde. CAE induced a dose-dependent increase in cell migration and invasion and also in the expression of cancer stem cells markers (CD133, CD44, CD90). CAE in Huh-7 cells selectively activated ERK1/2 and inhibited GSK3ß signaling pathways. Most of the changes induced by CAE were reversed after alcohol withdrawal. Interestingly, we confirmed the increase in CD133 mRNA levels in the tumoral tissue of patients with ethanol-related HCC compared to other HCC etiologies. Our results may explain the benefits observed in epidemiological studies showing a significant increase of overall survival in abstinent compared with non-abstinent patients.

Natural autoantibodies to Fcγ receptors in intravenous immunoglobulins.

A considerable progress has been achieved in the comprehension of the cellular and molecular mechanisms that account for the therapeutic benefit of intravenous immunoglobulin (IVIg) in several autoimmune and inflammatory conditions. However, the precise mechanisms responsible for such a wide range of biological activities have not been proven unambiguously. A wide range of specificities have been identified within IVIg including idiotypes of immunoglobulins, T cell receptor, HLA molecules, several cell surface molecules of immunological importance such as CD4, CD5, Fas, BAFF, cytokines and cytokine receptors, chemokine receptors, CD40 among others. Here we identify and characterize the natural autoantibodies of IgG isotype directed against the human Fc receptors. We show that the F(ab')2 of IVIg recognize the FcγRIII (CD16) and FcγRII (CD32). Interestingly, the immunopurified anti-FcγIII and anti-FcγII antibodies isolated from IVIg bind soluble and membrane-bound FcR and inhibit rosette formation. Altogether, these results along with previous reports provide pointers on the existence of functionally relevant natural autoantibodies towards a wide range of self-motifs that may participate in regulation of the immune response. Their presence in the therapeutic immunoglobulin preparations may explain at least in part, the beneficial effect of IVIg in autoimmune diseases.

Multi-faceted role of naturally occurring autoantibodies in fighting pathogens.

Naturally occurring antibodies (NAbs) play a vital role in the first line of defense against bacterial and viral infections. Most studies in mice and man have attributed this role to NAbs of the IgM isotype. However, there is also a significant amount of data on the anti-infectious function of NAbs of the IgG isotype. Most of these observations are derived from studies using a privileged source of NAbs, the pooled human IgG for intravenous application, IVIG. In addition to its use as a replacement in humoral immunodeficiencies, IVIG is extensively used in autoimmune and inflammatory diseases. The properties of NAbs, the principal components of IVIG, are considered crucial for their immune-regulatory properties, owing to their ability to recognize self-antigens and even autoantibodies. By virtue of these specificities for several cellular antigens, including exposed proteins that act as receptors for a variety of pathogens, certain NAbs in IVIG have a therapeutic role in preventing or modulating infections. We summarize in this chapter several examples that highlight the importance of NAbs in the control of certain bacterial and viral infections.

Rescuing SLAMF3 Expression Restores Sorafenib Response in Hepatocellular Carcinoma Cells through the Induction of Mesenchymal-to-Epithelial Transition.

BACKGROUND: Acquired resistance to sorafenib in hepatocellular carcinoma (HCC) patients results in poor prognosis. Epithelial-to-mesenchymal transition (EMT) is the major mechanism implicated in the resistance to sorafenib. We have reported the tumor suppressor role of SLAMF3 (signaling lymphocytic activation molecules family 3) in HCC progression and highlighted its implication in controlling the MRP-1 transporter activity. These data suggest the implication of SLAMF3 in sorafenib resistance mechanisms. METHODS: We evaluated the resistance to sorafenib in Huh-7 cells treated with progressive doses (Res cells). We investigated the link between acquired resistance to sorafenib and SLAMF3 expression by flow cytometry and Western blot methods. Furthermore, we analyzed the EMT and the stem cell potential of cells resistant to sorafenib. RESULTS: Sorafenib resistance was confirmed in Res cells by analyzing the cell viability in the presence of sorafenib. The mesenchymal transition, in Res cells, was confirmed by high migratory index and the expression of EMT antigens. Interestingly, we found that loss of SLAMF3 expression corresponded to sorafenib-resistant phenotypes. The overexpression of SLAMF3 reversed EMT, decreased metastatic potential and inhibited mTOR/ERK1/2 in Res cells. CONCLUSIONS: We propose that rescuing SLAMF3 expression in resistant cells could represent a potential therapeutic strategy to enhance sorafenib efficacy in HCC patients.

Differential activity of candidate microbicides against early steps of HIV-1 infection upon complement virus opsonization.

BACKGROUND: HIV-1 in genital secretions may be opsonized by several molecules including complement components. Opsonized HIV-1 by complement enhances the infection of various mucosal target cells, such as dendritic cells (DC) and epithelial cells. RESULTS: We herein evaluated the effect of HIV-1 complement opsonization on microbicide candidates' activity, by using three in vitro mucosal models: CCR5-tropic HIV-1JR-CSF transcytosis through epithelial cells, HIV-1JR-CSF attachment on immature monocyte-derived dendritic cells (iMDDC), and infectivity of iMDDC by CCR5-tropic HIV-1BaL and CXCR4-tropic HIV-1NDK. A panel of 10 microbicide candidates [T20, CADA, lectines HHA & GNA, PVAS, human lactoferrin, and monoclonal antibodies IgG1B12, 12G5, 2G12 and 2F5], were investigated using cell-free unopsonized or opsonized HIV-1 by complements. Only HHA and PVAS were able to inhibit HIV trancytosis. Upon opsonization, transcytosis was affected only by HHA, HIV-1 adsorption on iMDDC by four molecules (lactoferrin, IgG1B12, IgG2G5, IgG2G12), and replication in iMDDC of HIV-1BaL by five molecules (lactoferrin, CADA, T20, IgG1B12, IgG2F5) and of HIV-1NDK by two molecules (lactoferrin, IgG12G5). CONCLUSION: These observations demonstrate that HIV-1 opsonization by complements may modulate in vitro the efficiency of candidate microbicides to inhibit HIV-1 infection of mucosal target cells, as well as its crossing through mucosa.

Inhibition of HIV-1 transmission in trans from dendritic cells to CD4+ T lymphocytes by natural antibodies to the CRD domain of DC-SIGN purified from breast milk and intravenous immunoglobulins.

The present study demonstrates that human breast milk and normal human polyclonal immunoglobulins purified from plasma [intravenous immunoglobulins (IVIg)] contain functional natural immunoglobulin A (IgA) and IgG antibodies directed against the carbohydrate recognition domain (CRD) domain of the dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) molecule, which is involved in the binding of human immunodeficiency virus (HIV)-1 to dendritic cells (DCs). Antibodies to DC-SIGN CRD were affinity-purified on a matrix to which a synthetic peptide corresponding to the N-terminal CRD domain (amino-acid 342-amino-acid 371) had been coupled. The affinity-purified antibodies bound to the DC-SIGN peptide and to the native DC-SIGN molecule expressed by HeLa DC-SIGN+ cells and immature monocyte-derived dendritic cells (iMDDCs), in a specific and dose-dependent manner. At an optimal dose of 200 microg/ml, natural antibodies to DC-SIGN CRD peptide purified from breast milk and IVIg stained 25 and 20% of HeLa DC-SIGN+ cells and 32 and 12% of iMDDCs, respectively. Anti-DC-SIGN CRD peptide antibodies inhibited the attachment of virus to HeLa DC-SIGN by up to 78% and the attachment to iMDDCs by only 20%. Both breast milk- and IVIg-derived natural antibodies to the CRD peptide inhibited 60% of the transmission in trans of HIV-1(JRCSF), an R5-tropic strain, from iMDDCs to CD4+ T lymphocytes. Taken together, these observations suggest that the attachment of HIV to DCs and transmission in trans to autologous CD4+ T lymphocytes occur through two independent mechanisms. Our data support a role of natural antibodies to DC-SIGN in the modulation of postnatal HIV transmission through breast-feeding and in the natural host defence against HIV-1 in infected individuals.

Signaling lymphocytic activation molecules Slam and cancers: friends or foes?

Signaling Lymphocytic Activation Molecules (SLAM) family receptors are initially described in immune cells. These receptors recruit both activating and inhibitory SH2 domain containing proteins through their Immunoreceptor Tyrosine based Switch Motifs (ITSMs). Accumulating evidence suggest that the members of this family are intimately involved in different physiological and pathophysiological events such as regulation of immune responses and entry pathways of certain viruses. Recently, other functions of SLAM, principally in the pathophysiology of neoplastic transformations have also been deciphered. These new findings may prompt SLAM to be considered as new tumor markers, diagnostic tools or potential therapeutic targets for controlling the tumor progression. In this review, we summarize the major observations describing the implications and features of SLAM in oncology and discuss the therapeutic potential attributed to these molecules.

Early archives of genetically-restricted proviral DNA in the female genital tract after heterosexual transmission of HIV-1.

OBJECTIVES AND METHOD: In order to characterize human immunodeficiency virus type 1 (HIV-1) variants that are transmitted in women via heterosexual intercourse, the env V1-V3 sequences of HIV-1 provirus (DNA) and free virus (RNA) in paired samples of blood and cervicovaginal secretions of untreated chronically and primary infected African women were compared. RESULTS: Env RNA sequences retrieved from plasma and genital compartments formed a single cluster in primary infection. In contrast, env RNA sequences from these two compartments were distinct in chronically infected women. Analysis of proviral DNA of primary infected women showed that most HIV-1 sequences derived from the genital epithelia form independent clusters from HIV-1 sequences of DNA from peripheral blood mononuclear cells and RNA recovered from plasma and genital secretions. Similarly, the analysis of proviral DNA in the genital compartment of chronically infected women showed the persistence of genetically-restricted cluster of HIV-1. CONCLUSIONS: These observations indicate that a viral subpopulation is archived as proviral DNA in the female genital tract early in primary infection, and suggest that HIV-1 variants from the male donor are selected in the female mucosal site during male to female transmission of HIV-1.

HSV-2- and HIV-1- permissive cell lines co-infected by HSV-2 and HIV-1 co-replicate HSV-2 and HIV-1 without production of HSV-2/HIV-1 pseudotype particles.

BACKGROUND: Herpes simplex virus type 2 (HSV-2) is a major cofactor of human immunodeficiency virus type 1 (HIV-1) sexual acquisition and transmission. In the present study, we investigated whether HIV-1 and HSV-2 may interact at the cellular level by forming HIV-1 hybrid virions pseudotyped with HSV-2 envelope glycoproteins, as was previously reported for HSV type 1. METHODS: We evaluated in vitro the production of HSV-2/HIV-1 pseudotypes in mononuclear CEM cells and epithelial HT29 and P4P cells. We analyzed the incorporation into the HIV-1 membrane of HSV-2 gB and gD, two major HSV-2 glycoproteins required for HSV-2 fusion with the cell membrane, in co-infected cells and in HIV-1-infected P4P cells transfected by plasmids coding for gB or gD. RESULTS: We show that HSV-2 and HIV-1 co-replicated in dually infected cells, and gB and gD were co-localized with gp160. However, HIV-1 particles, produced in HIV-1-infected cells expressing gB or gD after transfection or HSV-2 superinfection, did not incorporate either gB or gD in the viral membrane, and did not have the capacity to infect cells normally non-permissive for HIV-1, such as epithelial cells. CONCLUSION: Our results do not support the hypothesis of HSV-2/HIV-1 pseudotype formation and involvement in the synergistic genital interactions between HIV-1 and HSV-2.

Influence of storage temperature on the stability of HIV-1 RNA and HSV-2 DNA in cervicovaginal secretions collected by vaginal washing.

Variability in the handling of samples of genital secretions prior to quantitation of HIV-1 RNA and HSV DNA may profoundly affect both the detection and quantitation of these nucleic acids. Over 144 h, we evaluated, the influence of storage temperature (4 degrees C, 20 degrees C, 30 degrees C) on the quantity of HIV-1 RNA and HSV-2 DNA in HIV and HSV negative cervicovaginal lavage pools spiked with known amounts of HIV-1 and HSV-2 and in HIV-1 and HSV-2 co-infected cervicovaginal lavage pools. The level of viral nucleic acids remained stable at 4 degrees C for 24h but decreased significantly when cervicovaginal lavages were stored at 20 degrees C and 30 degrees C, demonstrating that, cervicovaginal lavages to be quantified for viral RNA or DNA require, at minimum, immediate storage at 4 degrees C.

Hepatocyte SLAMF3 reduced specifically the multidrugs resistance protein MRP-1 and increases HCC cells sensitization to anti-cancer drugs.

Multidrug resistance MDR proteins (MRPs) are members of the C family of a group of proteins named ATP binding cassette (ABC) transporters. MRPs can transport drugs including anticancer drugs, nucleoside analogs, antimetabolites and tyrosine kinase inhibitors. Drugs used in HCC therapy, such as tyrosine kinase inhibitor sorafenib, are substrates of uptake and/or efflux transporters. Variable expression of MRPs at the plasma membrane of tumor cells may contribute to drug resistance and subsequent clinical response. Recently, we reported that the hepatocyte SLAMF3 expression (Signaling Lymphocytic Activation Molecule Family member 3) was reduced in tumor cells from hepatocellular carcinoma (HCC) compared to its high expression in adjacent tissues. In the present study, we make a strong correlation between induced SLAMF3 overexpression and the specific loss of MRP-1 expression and its functionalities as a drugs resistance transporter. No changes were observed on expression of ABCG2 and MDR. More importantly, we highlight a strong inverse correlation between MRP-1 and SLAMF3 expression in patients with HCC. We propose that the SLAMF3 overexpression in cancerous cells could represent a potential therapeutic strategy to improve the drugs sensibility of resistant cells and thus control the therapeutic failure in HCC patients.

RB/PLK1-dependent induced pathway by SLAMF3 expression inhibits mitosis and control hepatocarcinoma cell proliferation.

Polo-like kinase PLK1 is a cell cycle protein that plays multiple roles in promoting cell cycle progression. Among the many roles, the most prominent role of PLK1 is to regulate the mitotic spindle formation checkpoint at the M-phase. Recently we reported the expression of SLAMF3 in Hepatocytes and show that it is down regulated in tumor cells of hepatocellular carcinoma (HCC). We also show that the forced high expression level of SLAMF3 in HCC cells controls proliferation by inhibiting the MAPK ERK/JNK and the mTOR pathways. In the present study, we provide evidence that the inhibitory effect of SLAMF3 on HCC proliferation occurs through Retinoblastoma (RB) factor and PLK1-dependent pathway. In addition to the inhibition of MAPK ERK/JNK and the mTOR pathways, expression of SLAMF3 in HCC retains RB factor in its hypophosphorylated active form, which in turn inactivates E2F transcription factor, thereby repressing the expression and activation of PLK1. A clear inverse correlation was also observed between SLAMF3 and PLK expression in patients with HCC. In conclusion, the results presented here suggest that the tumor suppressor potential of SLAMF3 occurs through activation of RB that represses PLK1. We propose that the induction of a high expression level of SLAMF3 in cancerous cells could control cellular mitosis and block tumor progression.

The retinoblastoma (Rb) protein regulates ferroptosis induced by sorafenib in human hepatocellular carcinoma cells.

Sorafenib is the treatment of reference for advanced hepatocellular carcinoma (HCC), the most frequent form of primary liver tumour. The loss of function of the retinoblastoma (Rb) protein is an important event during liver carcinogenesis, but it is unclear whether the Rb status modulates the response of HCC cells to sorafenib. Here, we examined this question in HCC cells with reduced levels of Rb achieved through stable RNA interference. We show that HCC cells with reduced levels of Rb exhibit a two- to threefold increase in cell death induction upon exposure to sorafenib compared with controls. Sorafenib treatment of Balb/c nude mice that received tumour xenografts derived from HCC cells with reduced Rb levels resulted in complete tumour regression in 50% of the animals treated, compared with tumour stabilization in mice that received control cells. We show that, upon exposure to sorafenib, the Rb-negative status of HCC cells promotes the occurrence of ferroptosis, a form of oxidative necrosis. The findings highlight the role of Rb in the response of HCC cells to sorafenib and the regulation of ferroptosis.

The expression of the hepatocyte SLAMF3 (CD229) receptor enhances the hepatitis C virus infection.

Hepatitis C virus (HCV) is a leading cause of cirrhosis and liver cancer worldwide. We recently characterized for the first time the expression of Signaling Lymphocyte Activating Molecule 3 (SLAMF3) in human hepatocytes and here, we report that SLAMF3 interacts with the HCV viral protein E2 and is implicated in HCV entry process. We found a strong correlation between SLAMF3 expression level and hepatocyte susceptibility to HCV infection. The use of specific siRNAs to down-modulate SLAMF3 expression and SLAMF3-blocking antibodies both decreased the hepatocytes susceptibility to HCV infection. Moreover, SLAMF3 over-expression significantly increased susceptibility to HCV infection. Interestingly, experiments with peptides derived from each SLAMF3 domain showed that the first N-terminal extracellular domain is essential for interaction with HCV particles. Finally, we showed that recombinant HCV envelop protein E2 can bind SLAMF3 and that anti-SLAMF3 antibodies inhibited specifically this interaction. Overall, our results revealed that SLAMF3 plays a role during HCV entry, likely by enhancing entry of viral particle within hepatocytes.

Identification of SLAMF3 (CD229) as an inhibitor of hepatocellular carcinoma cell proliferation and tumour progression.

Although hepatocellular carcinoma (HCC) is one of the most common malignancies and constitutes the third leading cause of cancer-related deaths, the underlying molecular mechanisms are not fully understood. In the present study, we demonstrate for the first time that hepatocytes express signalling lymphocytic activation molecule family member 3 (SLAMF3/CD229) but not other SLAMF members. We provide evidence to show that SLAMF3 is involved in the control of hepatocyte proliferation and in hepatocellular carcinogenesis. SLAMF3 expression is significantly lower in primary human HCC samples and HCC cell lines than in human healthy primary hepatocytes. In HCC cell lines, the restoration of high levels of SLAMF3 expression inhibited cell proliferation and migration and enhanced apoptosis. Furthermore, SLAMF3 expression was associated with inhibition of HCC xenograft progression in the nude mouse model. The restoration of SLAMF3 expression levels also decreased the phosphorylation of MAPK ERK1/2, JNK and mTOR. In samples from resected HCC patients, SLAMF3 expression levels were significantly lower in tumorous tissues than in peritumoral tissues. Our results identify SLAMF3 as a specific marker of normal hepatocytes and provide evidence for its potential role in the control of proliferation of HCC cells.

Modulation of HIV Binding to Epithelial Cells and HIV Transfer from Immature Dendritic Cells to CD4 T Lymphocytes by Human Lactoferrin and its Major Exposed LF-33 Peptide.

Lactoferrin (LF), a multifunctional molecule present in human secretions, has potent inhibitory activities against human immunodeficiency virus (HIV). The aim of the study was to evaluate whether human LF (hLF) and its exposed domain LF-33 represented by the peptide (LF-33-GRRRRSVQWCAVSQPEATKCFQWQRNMRKVRGP) involved in LF-HIV gag binding and endotoxines neutralization, may inhibit early steps of HIV mucosal transmission. Human LF and the peptide LF-33 inhibited the attachment of primary X4-tropic HIV-1(NDK) and R5-tropic HIV-1(JR-CSF) strains to human endometrial (HEC-1) and colorectal (HT-29) CD4-negative epithelial cells, the purified hLF being more potent (up to 80%) than the LF-33 peptide. In addition, the hLF, but not the LF-33 peptide, inhibited up to 40% the transfer in trans of HIV-1(JR-CSF) and HIV-1(NDK,) from immature dendritic cells to CD4 T lymphocytes, likely in a DC-SIGN-dependent manner. Altogether, these findings demonstrate that hLF can interfere with HIV-1 mucosal transmission by blocking virus attachment to epithelial cells and by inhibiting virus transfer from dendritic cells to CD4 T cells, two crucial steps of HIV dissemination from mucosae to lymphoid tissue.

Apical interactions of HIV type 1 with polarized HEC-1 cell monolayer modulate R5-HIV type 1 spread by submucosal macrophages.

The in vitro model of HIV-1 transcytosis through a monolayer of HEC-1 cells is thought to mimic the mucosal crossing of the virus that may occur in vivo. We evaluated whether the stimulation of HEC-1 by HIV may modulate HIV infection of macrophages. Thus, the ability to capture, produce, and transfer R5 viruses to T cells, attract T cells, and finally produce cytokines/chemokines, was compared between untreated macrophages (M0) and macrophages differentiated in the presence of medium collected at the basolateral pole of HEC-1, which were unstimulated [M(BL)] or stimulated with either R5-HIV-1Ba-L [M(BL-R5)] or X4-HIV-1NDK [M(BL-X4)]. M(BL-X4)-secreted CCR5-interacting chemokines integrated and replicated HIV less efficiently than did M(BL) and M(BL-R5). M(BL-R5) and M(BL-X4) similarly transmitted HIV to activated T cells. Interestingly, mannose-binding receptors and heparan sulfate proteoglycans were variously involved in HIV adsorption, whereas DC-SIGN mostly mediated the HIV transfer. Conversely to M(BL) and M(BL-X4), M(BL-R5) did not secrete eotaxin, GRO, ITAC, lymphotactin, MIP-1, MIP-3, and RANTES, which was associated with a weak capacity to recruit CD4(+)CXCR4(+)CCR5(+) T cells. In particular, M(BL-R5) specifically released soluble factors enhancing HIV production by recruited T cells. These submucosal-conditioned macrophages differentially captured, produced, and transferred R5-HIV-1 to T cells, according to the tropism of the virus deposited at the apical pole of HEC-1. These observations challenge the question of the in vivo involvement of HIV-1 as a supraepithelial stimulus that likely modulates the susceptibility for HIV-1 of submucosal target cells in favor of its transmission.

Impact of acyclovir on genital and plasma HIV-1 RNA, genital herpes simplex virus type 2 DNA, and ulcer healing among HIV-1-infected African women with herpes ulcers: a randomized placebo-controlled trial.

BACKGROUND: Little is known about the impact of episodic treatment of herpes on human immunodeficiency virus type 1 (HIV-1). METHODS: Women from Ghana and the Central African Republic who had genital ulcers were enrolled in a randomized, double-blind, placebo-controlled trial of acyclovir plus antibacterials and were monitored for 28 days. Ulcer etiologies and detection of lesional HIV-1 RNA were determined by polymerase chain reaction (PCR). Cervicovaginal HIV-1 RNA and herpes simplex virus type 2 (HSV-2) DNA and plasma HIV-1 RNA were quantitated by real-time PCR. Primary analyses included 118 HIV-1-infected women with HSV-2 ulcers (54 of whom were given acyclovir and 64 of whom were given placebo). RESULTS: Acyclovir had little impact on (1) detection of cervicovaginal HIV-1 RNA (risk ratio [RR], 0.96; 95% confidence interval [CI], 0.8-1.2) at day 7 of treatment, (2) the mean cervicovaginal HIV-1 RNA load (-0.06 log(10) copies/mL; 95% CI, -0.4 to 0.3 log(10) copies/mL) at day 7 of treatment, or (3) the plasma HIV-1 RNA load (+0.09 log(10) copies/mL; 95% CI, -0.1 to 0.3 log(10) copies/mL) at day 14 of treatment. At day 7, women receiving acyclovir were less likely to have detectable lesional HIV-1 RNA (RR, 0.70; 95% CI, 0.4-1.2) or cervicovaginal HSV-2 DNA (RR, 0.69; 95% CI, 0.4-1.3), had a lower quantity of HSV-2 DNA (-0.99 log(10) copies/mL; 95% CI, -1.8 to -0.2 log(10) copies/mL), and were more likely to have a healed ulcer (RR, 1.26; 95% CI, 0.9-1.9). CONCLUSION: Episodic therapy for herpes reduced the quantity of cervicovaginal HSV-2 DNA and slightly improved ulcer healing, but it did not decrease genital and plasma HIV-1 RNA loads. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT00158483 .

Neutralizing monoclonal antibodies to human immunodeficiency virus type 1 do not inhibit viral transcytosis through mucosal epithelial cells.

HIV-1 transcytosis has been proposed as a potential mechanism allowing the virus to cross the epithelium during mucosal transmission. Epitopes of the HIV-1 envelope involved in this process have not been identified yet. Here, we assessed a large panel of HIV neutralizing antibodies recognizing well-characterized epitopes of the HIV-1 envelope for their ability to block HIV-1 transcytosis across a confluent epithelial monolayer. We found that all of the 13 HIV-1-specific monoclonal antibodies tested in the present study, including the three broadly neutralizing antibodies 2F5, 2G12 and IgG1b12, lacked the ability to inhibit transcytosis of cell-free and cell-associated R5- as X4-tropic HIV-1 across a tight and polarized monolayer of HEC-1 epithelial cells. In contrast, anti-gp160 polyclonal antibodies purified from serum or breast milk of HIV-1-infected individuals potently inhibited HIV-1 transcytosis. Furthermore, polymeric S-IgA exhibited similar ability to inhibit transcytosis compared to IgG despite their lower anti-gp160 specific activity. Together, these results demonstrate that the major neutralizing envelope epitopes of HIV-1 are not involved in HIV-1 transcytosis, and suggest that surface agglutination of virus particles may participate to the blocking effect observed with both polyclonal and polymeric anti-gp160 immunoglobulins.

Infection of macrophages and dendritic cells with primary R5-tropic human immunodeficiency virus type 1 inhibited by natural polyreactive anti-CCR5 antibodies purified from cervicovaginal secretions.

Heterosexual contact is the primary mode of human immunodeficiency virus (HIV) type 1 (HIV-1) transmission worldwide. The chemokine receptor CCR5 is the major coreceptor that is associated with the mucosal transmission of R5-tropic HIV-1 during sexual intercourse. The CCR5 molecule is thus a target for antibody-based therapeutic strategies aimed at blocking HIV-1 entry into cells. We have previously demonstrated that polyreactive natural antibodies (NAbs) from therapeutic preparations of immunoglobulin G and from human breast milk contain NAbs directed against CCR5. Such antibodies inhibit the infection of human macrophages and T lymphocytes by R5-tropic isolates of HIV in vitro. In the present study, we demonstrate that human immunoglobulins from the cervicovaginal secretions of HIV-seronegative or HIV-seropositive women contain NAbs directed against the HIV-1 coreceptor CCR5. Natural affinity-purified anti-CCR5 antibodies bound to CCR5 expressed on macrophages and dendritic cells and further inhibited the infection of macrophages and dendritic cells with primary and laboratory-adapted R5-tropic HIV but not with X4-tropic HIV. Natural anti-CCR5 antibodies moderately inhibited R5-tropic HIV transfer from monocyte-derived dendritic cells to autologous T cells. Our results suggest that mucosal anti-CCR5 antibodies from healthy immunocompetent donors may hamper the penetration of HIV and may be suitable for use in the development of novel passive immunotherapy regimens in specific clinical settings of HIV infection.