Marie-José Truong

Interleukin-16 (IL-16) Inhibits Human Immunodeficiency Virus Replication in Cells from Infected Subjects, and Serum IL-16 Levels Drop with Disease Progression

The role of recombinant interleukin-16 (rIL-16) in regulating human immunodeficiency virus type 1 (HIV-1) replication in endogenously infected cells has been investigated. Cultures of CD8 cell-depleted mitogen-activated lymphocytes from 22 of 26 HIV-1-infected subjects presented variable levels of secreted p24 antigen. The presence of rIL-16 throughout the 14-day culture period dramatically inhibited p24 release into the culture supernatants. This effect was found to be mediated through inhibition of viral transcription but to be independent of the induced levels of other cytokines or chemokines known to regulate viral replication. Analysis of serum samples from HIV-1-infected subjects over a period of 8 years showed maintained or even increased IL-16 levels during the whole asymptomatic phase and a significant drop on progression to disease. These results strongly support a potential therapeutic value of rIL-16 in HIV-1 infection and the use of serum IL-16 levels to monitor disease progression.

The Synthetic Immunomodulator Murabutide Controls Human Immunodeficiency Virus Type 1 Replication at Multiple Levels in Macrophages and Dendritic Cells

ABSTRACT Macrophages and dendritic cells are known to play an important role in the establishment and persistence of human immunodeficiency virus (HIV) infection. Besides antiretroviral therapy, several immune-based interventions are being evaluated with the aim of achieving better control of virus replication in reservoir cells. Murabutide is a safe synthetic immunomodulator presenting a capacity to enhance nonspecific resistance against viral infections and to target cells of the reticuloendothelial system. In this study, we have examined the ability of Murabutide to control HIV type 1 (HIV-1) replication in acutely infected monocyte-derived macrophages (MDMs) and dendritic cells (MDDCs). Highly significant suppression of viral replication was consistently observed in Murabutide-treated cultures of both cell types. Murabutide did not affect virus entry, reverse transcriptase activity, or early proviral DNA formation in the cytoplasm of infected cells. However, treated MDMs and MDDCs showed a dramatic reduction in nuclear viral two-long terminal repeat circular form and viral mRNA transcripts. This HIV-1-suppressive activity was not mediated by inhibiting cellular DNA synthesis or by activating p38 mitogen-activated protein kinase. Furthermore, Murabutide-stimulated cells expressed reduced CD4 and CCR5 receptors and secreted high levels of β-chemokines, although neutralization of the released chemokines did not alter the HIV-1-suppressive activity of Murabutide. These results provide evidence that a clinically acceptable immunomodulator can activate multiple effector pathways in macrophages and in dendritic cells, rendering them nonpermissive for HIV-1 replication.

SS-56, a novel cellular target of autoantibody responses in Sjögren syndrome and systemic lupus erythematosus

Certain autoimmune disorders, including Sjögren syndrome (SS) and systemic lupus erythematosus (SLE), are characterized by autoantibodies against the Ro/SSA and La/SSB cellular antigens. Although the implication of these autoantibodies in disease pathogenesis is still unclear, it is believed that the aberrant responses against autoantigens may extend to other proteins that are not yet well defined. In an attempt to analyze the regulated gene expression in lymphocytes by an HIV-suppressive immunomodulator, we have identified and cloned a novel gene encoding a 56-kDa protein, named SS-56, which is structurally related to the 52-kDa Ro/SSA antigen. The new protein showed primarily perinuclear cytoplasmic localization, and recombinant SS-56 was found to react in ELISA with sera from most patients with SS or SLE. Western blot analysis confirmed the autoantigenic nature of native SS-56 in extracts from HeLa cells. Interestingly, the incidence of antibodies to SS-56 was associated with visceral complications in SLE, and roughly half of the 17 SS or SLE patients with no detectable antibodies to SSA and SSB antigens presented measurable antibodies against recombinant SS-56. Thus, SS-56 represents a new member of the SS family of autoantigens and could become an additional and important diagnostic marker for SS and SLE.

Selective Regulation of Human Immunodeficiency Virus-Infected CD4+ Lymphocytes by a Synthetic Immunomodulator Leads to Potent Virus Suppression In Vitro and in hu-PBL-SCID Mice

ABSTRACT We have previously observed that the synthetic immunomodulator Murabutide inhibits human immunodeficiency virus type 1 (HIV-1) replication at multiple levels in macrophages and dendritic cells. The present study was designed to profile the activity of Murabutide on CD8-depleted phytohemagglutinin-activated lymphocytes from HIV-1-infected subjects and on the outcome of HIV-1 infection in severe combined immunodeficiency mice reconstituted with human peripheral blood leukocytes (hu-PBL-SCID mice). Maintaining cultures of CD8-depleted blasts from 36 patients in the presence of Murabutide produced dramatically reduced levels of viral p24 protein in the supernatants. This activity correlated with reduced viral transcripts and proviral DNA, was evident in cultures harboring R5, X4-R5, or X4 HIV-1 isolates, was not linked to inhibition of cellular DNA synthesis, and did not correlate with β-chemokine release. Moreover, c-myc mRNA expression was down-regulated in Murabutide-treated cells, suggesting potential interference of the immunomodulator with the nuclear transport of viral preintegration complexes. On the other hand, daily treatment of HIV-1-infected hu-PBL-SCID mice with Murabutide significantly reduced the viral loads in plasma and the proviral DNA content in human peritoneal cells. These results are the first to demonstrate that a clinically acceptable synthetic immunomodulator with an ability to enhance the hosts nonspecific immune defense mechanisms against infections can directly regulate cellular factors in infected lymphocytes, leading to controlled HIV-1 replication.

Eosinophil IgE receptor and CD23

In the present review, eosinophil FcεRII was compared to CD23, a differentiation marker of B cells. Biochemical analysis revealed that molecules of similar molecular weight were immunoprecipitated from eosinophils and B cells by an anti-CD23 monoclonal antibody (mAb) or by BB10, an anti-eosinophil FcεRII. By flow cytometry, a correlation was found between the binding of anti-CD23 mAb and myeloma IgE. However, a low expression of different epitopes of CD23 was observed in various hypereosinophilic patients. Northern blot analysis of eosinophil RNA with the cDNA probe of CD23 revealed a weak message in only 3 of the 6 patients expressing membrane CD23. The inhibition by anti-CD23 mAbs of IgE-mediated cytotoxicity and IgE binding to eosinophils clearly indicated the participation of CD23 or a related moclecule in IgE-dependent eosinophil functions. However, the differential effects of anti-CD23 mAbs on eosinophils and B cells suggest major differences in the characteristics of the molecule expressed by eosinophils and by B cells.