Mutual interactions between HIV-1 and cytokines in adherent cells during acute infection

Type III and I interferons increase HIV uptake and replication in human cells that overexpress CD4, CCR5, and CXCR4

The newly discovered type III interferon lambda (IFN-lambda) has antiviral activity against a broad spectrum of viruses and potent immune-related activities. Its major producers are peripheral blood mononuclear cells (PBMCs) and dendritic cells. The above functions and cells are deeply involved in AIDS pathogenesis, but there is no information so far on IFN-lambda effects on HIV. Therefore we addressed the sensitivity of HIV-1 replication to cell exposure to human IFN-lambda2. Human PBMCs and C8166 T cells were treated with human Type III or Type I IFNs, and the ability of HIV-1 to bind and replicate in untreated and IFN-treated cells was investigated. Virus amounts were quantified by infectivity and p24 assays. In parallel, we evaluated the possible antiproliferative effects of IFN-lambda2 and the expression of CD4, CXCR4, and CCR5 genes, whose transcripts were quantified by real time RT-PCR. Data showed increased adsorption of HIV to IFN-treated cells in a dose-dependent fashion. Virus yields increased accordingly. In both systems the accumulation of CD4, CXCR4, and CCR5 transcripts was increased, particularly in PBMCs. Antiproliferative activity and classical antiviral state were instead detected on PBMCs, but not on C8166 cells. We concluded that pretreatment of PBMCs and C8166 cells with Type III and Type I IFNs causes increased HIV binding and replication. These effects are likely to be due to increased expression of HIV receptors and coreceptors on the plasma membrane. These findings indicate another mechanism utilized by HIV for subversion of host defenses.

HIV-1: maternal prognosis

Profound modifications in the profile of patients are currently being observed within the epidemic context of AIDS, especially with respect to pauperization and feminization of the disease. The population most frequently affected is in the reproductive age, and among adults aged 18 to 24 years, the ratio is 1 man to 1 woman, a phenomenon occurring uniformly all over the world. One of the main challenges for HIV-1-infected pregnant women and their doctors is the effect of the interaction between HIV infection and pregnancy. The present article is a review of the literature; and its objective is to assess the influence of HIV-1 infection seen from the maternal perspective, with a discussion of immunologic function, maternal prognosis, and the HIV-abortion interface. At present, we cannot conclude that pregnancy has a short-term effect on the evolution of HIV infection, but the concomitance of HIV and pregnancy may adversely affect the prognosis of gestation, especially in view of its frequent association with increased abortion and puerperal morbidity rates.

In vitro modulation of the multiple sclerosis (MS)-associated retrovirus by cytokines: implications for MS pathogenesis

Multiple sclerosis (MS)-associated retrovirus (MSRV) is a component of the human endogenous retrovirus (HERV)-W family, with gliotoxic and superantigenic properties, related to MS clinical progression, and transactivated by viral agents. The authors studied MSRV modulation by cytokines involved in vivo in MS course, utilizing peripheral blood mononuclear cells from MSRV-positive and MRSV-negative individuals. Cultured cells from MSRV-negative subjects did not produce virus, whereas spontaneous MSRV release was detected in cultures from MSRV-positive donors; virus release was increased by interleukin (IL)-4 and IL-6 and, to a greater extent, by the detrimental cytokines interferon gamma and tumor necrosis factor (TNF)alpha. Interferon beta, used in MS therapy, inhibits MSRV release. A parallel between the effects of these cytokines on MSRV production in vitro and on MS disease in vivo is observed, which deserves further elucidations.

Characterization of an HIV type 1 strain with preferential replication in adherent cells

HIV-E, emerging from persistently infected HeLa-T4 cells, replicates better in fibroblasts and epithelial cells with respect to the parental, T cell-derived HIV-T. The two viruses share the same env V3 loop, but differ in cellular molecules incorporated on the envelope. Even when similar amounts of virus attachment occurred, HIV-E replicated better than HIV-T in cells from solid tissues, and the response to exogenous Tat was more efficient. This might be related to the long terminal repeat (LTR), because HIV-E has a TAR duplication, and a mutation in the Sp1-II binding site. Epithelial cells deserve further study, because they may be important in vivo for variant selection and latency.

Immunomodulation by nitrite inhalants may predispose abusers to AIDS and Kaposi's sarcoma

Epidemiological studies indicating that nitrite inhalant abuse is a co-factor in HIV infection and in Kaposi's sarcoma are supported by recent experimental studies, described in this review. Inhalation exposure to the nitrites produce a nonspecific cytotoxicity, depleting many cells of the immune system. Apparently distinct from this cytotoxicity, inhalation of the nitrites impairs a variety of immune mechanisms, affecting both humoral and cell-mediated immunity. In addition, the inhalant-increased macrophage production of the inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha), can directly stimulate HIV replication and can also stimulate the growth of Kaposi's sarcoma cells. Thus, nitrite inhalants may impair immune resistance to infection and actively promote viral replication and tumor growth.

The influence of pregnancy on human immunodeficiency virus type 1 infection: antepartum and postpartum changes in human immunodeficiency virus type 1 viral load

OBJECTIVE

Our objective was to examine the influence of pregnancy on human immunodeficiency virus type 1 viral load by measuring human immunodeficiency virus type 1 ribonucleic acid levels during pregnancy and post partum.

STUDY DESIGN

One or more plasma or serum specimens obtained before and during the third trimester, and at 2, 12, and 24 months post partum were available for 160 human immunodeficiency virus type 1-seropositive women enrolled in the Mothers and Infants Cohort Study between January 1986 and January 1991. All specimens were frozen and stored at -70 degrees C until analyzed in batch for human immunodeficiency virus type 1 ribonucleic acid by polymerase chain reaction. A multivariate longitudinal random effects model was developed to examine changes in human immunodeficiency virus type 1 ribonucleic acid levels over time.

RESULTS

Overall, human immunodeficiency virus type 1 ribonucleic acid levels rose significantly during the study period, particularly during the second year post partum (mean, 0.09 log per year; 95% confidence interval, 0.03 to 0.15 logs per year; p = 0.005). However, the mean slope during pregnancy was not significantly different from zero (p = 0.65).

CONCLUSION

Pregnancy had little immediate effect on human immunodeficiency virus type 1 viral load in most human immunodeficiency virus type 1-seropositive women.

Productive HIV-1 infection of human vascular endothelial cells requires cell proliferation and is stimulated by combined treatment with interleukin-1 beta plus tumor necrosis factor-alpha

Vascular endothelial cells (EC) play a key role in viral tropism in vivo. Since conflicting reports have been published on the capability of HIV to infect EC in vitro, we analyzed some factors potentially capable of influencing the susceptibility of human umbilical vein endothelial cells (HUVEC) to HIV-1. Both primary cultures and differentiated immortalized HUVEC lines were used. HUVEC were negative for the expression of CD4, but weakly CD26- and galactosylceramide-positive. Although binding of HIV to EC was substantial, the virus was apparently incapable of replicating in nonproliferating cultures. In resting cultures, the content of cell-associated HIV disappeared 4-6 days after infection without production of p24 and infectious progency. In contrast, infection of proliferating EC cultures led to the transient release of p24 and infectious virus (10(2.5)-10(3.5) SFU/ml) peaking 2-6 days postinfection. Antibody neutralization of cytokines that may be produced by EC (IL1, IL6, IL8, TNF, IFN-beta) failed to modify virus adsorption and replication, whereas treatment with IL1-beta plus TNF-alpha stimulated both virus binding and virus release. As seen by gag polymerase chain reaction (PCR), the viral genome persisted up to 15 days in untreated EC cultures, but over 20 days in cultures exposed to IL1-beta plus TNF-alpha. This study shows that: (a) CD4-negative HUVEC are capable of binding substantial amounts of HIV-1; (b) binding is enhanced by proinflammatory cytokines; (c) the establishment of productive infection is favored by cell proliferation; and (d) exposure to IL1-beta plus TNF-alpha enhances virus replication.

HIV type 1 grown on interferon gamma-treated U937 cells shows selective increase in virion-associated intercellular adhesion molecule 1 and HLA-DR and enhanced infectivity for CD4-negative cells

Cellular adhesion molecules, such as ICAM-1, -2, and -3; LFA-1; and HLA class I and II are incorporated into HIV-1 virions during budding from infected cells. These virion-associated molecules can be involved in the adsorption to susceptible cells displaying the corresponding counterligands. A number of cytokines have been shown to upregulate the cellular expression of adhesion molecules, such as ICAM-1 and HLA-DR. In this study we investigated the effects of IFN-gamma on the incorporation of ICAM-1, LFA-1, and HLA-DR into mature HIV-1 progeny from chronically infected cells. The ability of such virus progeny to infect either CD4-positive or -negative cells was also investigated. The results indicate that IFN-gamma stimulates the expression of ICAM-1 and of HLA-DR on HIV-1-infected cells, whereas LFA-1 expression is unaffected. The same modifications were also observed on virus progeny, because specific MAbs to ICAM-1 and HLA-DR captured infectious HIV-1 from IFN-treated cells with higher efficiency as compared to virus from control cells, whereas virus binding to anti LFA-1 MAb was unchanged. Moreover, the HIV-1 progeny released from IFN-treated cells showed an increased ability to bind to and to infect CD4-negative cells, whereas the infectivity was basically unchanged for CD4-positive cells. Our results suggest that cytokines, as well as other soluble factors, may expand the host cell range of HIV-1, possibly through modifications of the cell-derived surface molecules on the virions.(ABSTRACT TRUNCATED AT 250 WORDS)

Infectious virus with reduced cytopathogenicity resulting from persistent infection of normal lung fibroblasts by HIV type 1 strains

We asked whether HIV-1 had the capacity to establish a persistent infection of cultured human diploid fibroblasts. Human strains of normal diploid embryo lung fibroblasts were infected with HIV-1 of the HTLV-IIIB and HIV-1P1 strains. Infection was followed over time, to analyze HIV expression. Virus production (intra- and extracellular virus) was evaluated as follows: ability to form syncytia in the C8166 T cell line, production of p24 and other viral antigens (ELISA and indirect immunofluorescence), search for a gag sequence in cell DNA by the polymerase chain reaction followed by hybridization to an HIV-1-specific probe (SK19). Cell-free culture supernatant was used as a virus source to infect de novo fibroblasts and C8166 T cells. Infection of cultured fibroblasts with either the HTLV-IIIB or HIV-1P1 strain led regularly to the establishment of persistently infected cultures. Fibroblast cells were capable of continuous virus production for at least 10 months. The released virus was capable of reinfecting cultured fibroblasts and of producing cytopathic effects in the C8166 T cell line. However, when compared to wild-type strains, the infectious virus derived from fibroblasts showed a prolonged replication cycle and a decreased ability to form syncytia in the T cell line. Therefore, HIV-1 can establish a persistent and productive infection in normal lung fibroblasts. The data are consistent with the hypothesis that in vivo, at least in the lung, fibroblasts may represent a virus reservoir and that infection of these cells may lead to the production of attenuated variants of HIV.