广西地区HIV合并结核感染及其他因素对HIV复制影响的研究

目的 分析合并结核( tuberculosis,TB)感染及其他因素对广西地区HIV感染者病毒复制的影响.方法 2010年4月至2010年9月间在广西招募到未接受抗病毒治疗、CD4+T细胞数＜350个/μl的HIV/TB感染者61例,单纯HIV感染者34例.收集人口学、流行病学、临床信息,测定HIV病毒载量.结果 HIV/TB双重感染者与单纯HIV感染者血浆病毒载量差异无统计学意义[ (5.05±0.93) lg拷贝/ml vs (5.06±0.76) lg拷贝/ml,P=0.94].二元logistic回归分析显示,CRF01_AE亚型较其他亚型HIV感染者血浆病毒复制水平高,OR=8.07 (95％CI 1.07～61.20,P=0.04).年龄、感染途径、CD4+T细胞数,是否合并结核分枝杆菌(MTB)感染及TB临床类型对病毒复制水平的影响均不明显.结论 广西地区CD4+T细胞数较低的HIV感染者中,合并结核感染对病毒复制影响不明显;CRF01_AE亚型HIV-1病毒复制水平较高,在监测和治疗过程中需加强关注.     

Entry and intracellular replication of Mycobacterium tuberculosis in cultured human microvascular endothelial cells

Establishment of pulmonary Mycobacterium tuberculosis infection requires evasion of host innate defenses. In the lung alveoli, epithelial cells naturally resist uptake by the inhaled bacilli while macrophages patrol the epithelial surface and phagocytose foreign microbes. Alveolar microvascular endothelial cells, however, have not been examined as a potential point of direct interaction with the bacilli. It has been shown with other bacterial and viral lung pathogens that the lung endothelial cells are not only a point of interaction, but a source for intracellular replication and chronic infection by the pathogen. To investigate if endothelial cells are susceptible to M. tuberculosis infection, we examined attachment, internalization, and intracellular replication of M. tuberculosis bacilli in an immortalized human lung microvascular endothelial cell line (HULEC). By 6 h post-infection, 12% of infecting bacilli were associated with the HULEC monolayer cells. This was twice the association observed following a similar infection with cells from a human foreskin microvascular endothelial cell line (HMEC-1). As measured by survival after the addition of a high extracellular concentration of the aminoglycoside amikacin, approximately one-third of the associated bacilli were internalized and unavailable to the drug in both cell lines. Using electron microscopy, large numbers of bacilli were visible in the vacuoles of HULEC cells after 48 h post-infection; the presence of bacterial septa between adjacent mycobacteria suggests intracellular replication. These in vitro findings support the hypothesis that lung endothelial cells have the potential to participate in in vivo lung infections.     

Impact of tuberculosis on HIV-1 replication,diversity, and disease progression

HIV and Mycobacterium tuberculosis not only co-circulate throughout the developing world but each has contributed to prevalence and mortality caused by the other. Several reports have described how HIV-1 increases the incidence of new M. tuberculosis infections, exacerbates the severity of tuberculosis (TB), and re-activates latent M. tuberculosis. However, the converse relationship is more difficult to understand considering TB can emerge in asymptomatic individuals and as an opportunistic infection during AIDS. Development of TB in HIV infected individuals with higher CD4 cell counts (> 200/mm3) appears to increase the rate of disease progression and mortality. Higher viral loads, increased HIV-1 diversity, and changes in cytokine/chemokine levels in HIV-infected individuals with TB appear to be related to a localized immune stimulation. Specifically, increased levels of TNF alpha and MCP-1, induced by TB, may activate HIV replication in lymphocytes, monocytes, and macrophages that are resident or have migrated to M. tuberculosis infected organs (e.g. pleura or lung). The HIV-1 found in blood following this TB-mediated burst in load and diversity appear to be phylogenetically-related to HIV-1 clones that have evolved independently in the lung or pleural compartments, now infected by M. tuberculosis.     

Treatment with valacyclovir, famciclovir, or antiretrovirals reduces human herpesvirus-8 replication in HIV-1 seropositive men

Human herpesvirus‐8 (HHV‐8) replication is a key factor in Kaposi sarcoma, primary effusion lymphoma, and Castleman disease pathogenesis. In vitro data suggest that antivirals inhibit HHV‐8 replication, but little data exist in humans. Daily oropharyngeal swabs were analyzed from HIV/HHV‐8 dually infected men enrolled in three previous clinical trials of valacyclovir and famciclovir for HIV‐1 and/or HSV‐2 suppression. Fifty‐eight participants contributed 6,036 swabs. HHV‐8 was detected in 1,128 (19%) of 6,036 swabs, including 618 (21%) of 2,992 on placebo, 323 (15%) of 2,221 on valacyclovir, and 187 (23%) of 823 on famciclovir. After adjusting for baseline HIV viral load and highly active antiretroviral therapy (HAART) use, an 18% reduction in HHV‐8 shedding frequency (IRR 0.822; P = 0.011) was found in participants on valacyclovir and a 30% reduction (IRR 0.700; P < 0.001) on famciclovir. HAART was associated with an 89% (IRR 0.129; P = 0.048) reduction in HHV‐8‐shedding. Neither antiviral nor antiretroviral therapy was associated with decreased HHV‐8 quantity. Valacyclovir and famciclovir were associated with modest but significant reductions in HHV‐8 oropharyngeal shedding frequency. In contrast, HAART was a potent inhibitor of HHV‐8 replication. Studies of whether antiviral therapy in combination with ART will prevent HHV‐8‐associated disease appear warranted. J. Med. Virol. 83:1696–1703, 2011. © 2011 Wiley‐Liss, Inc.     

Increased Mycobacterium tuberculosis growth in HIV-1-infected human macrophages: role of tumour necrosis factor-alpha

Synergism between Mycobacterium tuberculosis (M. tuberculosis) and HIV-1 infections was demonstrated in several in vitro models and clinical studies. Here, we investigated their reciprocal effects on growth in chronically HIV-1-infected promonocytic U1 cells and in acutely infected monocyte-derived macrophages (MDM). Phagocytosis of M. tuberculosis induced HIV-1 expression in U1 cells, together with increased TNF-alpha production. M. tuberculosis growth, evaluated by competitive PCR, was greater in HIV-1-infected MDM compared to uninfected cells. M. tuberculosis phagocytosis induced greater TNF-alpha and IL-10 production in HIV-1-infected MDM than in uninfected cells. In uninfected MDM, addition of TNF-alpha and IFN-gamma decreased, whereas IL-10 increased M. tuberculosis growth. On the contrary, in HIV-1-infected MDM, addition of TNF-alpha and IFN-gamma increased, whereas IL-10 has no effect on M. tuberculosis growth. TNF-alpha seems to play a pivotal role in the enhanced M. tuberculosis growth observed in HIV-1-infected MDM, being unable to exert its physiological antimycobacterial activity. Here, for the first time we demonstrated an enhanced M. tuberculosis growth in HIV-1-infected MDM, in line with the observed clinical synergism between the two infections.     

EB病毒转化淋巴母细胞LMP-1,LMP-2A及LMP-2B的表达

目的了解EB病毒转化淋巴母细胞LMP-1,LMP-2A,LMP-2B基因的表达改变。方法采用实时定量PCR方法分别检测并比较同一献血员来源的正常人淋巴细胞与EBV转化淋巴母细胞前后LMP基因(LMP-1、LMP-2A、LMP-2B)的表达改变。采用Western bolt检测LMP-1蛋白表达。结果 LMP-1、LMP-2A、LMP-2B基因在转化淋巴母细胞比在正常人淋巴细胞的表达分别上调863倍、1 763倍、90 078倍。Western bolt检测LMP-1蛋白在转化淋巴母细胞中的表达比正常人淋巴细胞明显增强。结论在EBV转化淋巴母细胞过程中LMP-1、LMP-2A和LMP-2B表达均上调。     

Restriction of HIV-1 replication in promonocytic cells: a role for IFN-alpha

A comparative study of the replication kinetics of human immunodeficiency virus type 1 (HIV-1) was performed in the promonocytic U937 cells and in the T lymphoblastoid H9 cells. If a productive HIV-1 infection of both cell types could be established, the time which elapses before most of the cells could express viral proteins is always proportionally longer for U937 cells than for H9 cells. Indeed, when U937 cells are infected with HIV-1, this nonproductive phase is followed by a lag phase during which the percentage of virus-producing cells is slowly increasing when compared to H9 cells. The restriction of HIV-1 replication in U937 cells might be consecutive to the lower adsorption of viral particles to these cells, even though the same percentage of U937 and H9 cells was expressing the CD4 molecule. Furthermore, we demonstrate that HIV-1 replication in U937 cells is mainly restricted by endogenous IFN-alpha. Indeed, addition of anti-IFN-alpha antibodies at the time of infection, during the nonproductive phase of the viral replication cycle, or during the lag phase leads to an earlier expression of viral proteins and/or to a rapid increase in the percentage of virus-producing cells. Likewise, the treatment of cultures of HIV-1 chronically infected U937 cells with the same antibodies induces an increased production of viral particles. Thus, IFN-alpha appears to be involved in the persistence of HIV-1 in the monocytes/macrophages of infected individuals.     

Survival and replication of clinical Mycobacterium tuberculosis isolates in the context of human innate immunity

The initial host response to Mycobacterium tuberculosis is driven by innate immunity. For this study, we examined the ability of 18 recent clinical isolates and 5 reference strains to survive and replicate in the context of host innate immunity by using whole blood culture. Six healthy tuberculin-negative volunteers served as subjects. H(37)Ra showed the least capacity to replicate of any of the strains tested, decreasing in viability 1.3 log CFU during 72 h of whole blood culture, whereas H(37)Rv increased 0.32 log. Clinical isolates varied greatly in their ability to replicate in blood cells, ranging from -0.4 to +0.8 log (P < 0.001). Four showed significantly more growth than H(37)Rv, and one showed significantly reduced growth. Host mechanisms for restricting intracellular mycobacterial growth were more effective during the first 24 h of whole blood culture than during the 24- to 72-h period. Certain mycobacterial isolates appeared preferentially able to withstand host defenses during each of these intervals. Although there was relatively more homogeneity among subjects than among strains, one of the six subjects showed a reduced capacity to restrict intracellular mycobacterial growth due to a defect expressed during the first 24 h of culture. Our findings indicate substantial variability in the capacity of clinical tuberculosis isolates to replicate in host cells in the face of innate host immunity.     

CD 4-positive lymphoid cells rescue HIV-1 replication from abortively infected human primary endothelial cells

Summary Human primary endothelial cell cultures, derived from umbilical vein (HUVEC), can be infected by different strains of HIV-1, but mature virus production remains undetectable both in supernatants and in cellular extracts. Yet viral DNA is transiently detectable during the first days of infection, but progressively declines during the subsequent days. This finding is characteristic of abortive infections. Co-culture of HUVEC carrying HIV DNA with activated peripheral blood mononuclear cells or with CD 4-positive lymphoid cells elicited a massive cpe (syncytia formation and cell degeneration) in the latter cells, caused by the establishment of productive HIV-1 infection. HUVEC infected in the presence of AZT were significantly impaired in the ability to transmit the infection of CD 4-positive cells, indicating that active DNA synthesis is required in HUVEC before rescue by CD 4-positive cells.These results are of interest in view of the possibility that endothelial cells can play a role in the transmission of HIV-1 infection from infected pregnant women to the foetuses, and, more generally, suggest a potential role of endothelial cells as a transient reservoir of HIV-1.     

Macrophage migration inhibitory factor reduces the growth of virulent Mycobacterium tuberculosis in human macrophages

Macrophage migration inhibitory factor (MIF) is a key mediator of the innate immune system and plays a crucial role in the host response to bacterial infections. Its role in immunity to intracellular pathogens has not been well studied. Here, we show that MIF released by infected human macrophages inhibits the growth of virulent Mycobacterium tuberculosis.     

Signaling pathways triggered by HIV-1 Tat in human monocytes to induce TNF-alpha

In this study we investigated the signaling pathways triggered by Tat in human monocyte to induce TNF-alpha. In monocytes, the calcium, the PKA, and the PKC pathways are highly implicated in the expression of cytokine genes. Thus, these three major signaling pathways were investigated. Our data show that (i) PKC and calcium pathways are required for TNF-alpha production, whereas the PKA pathway seems to be not involved; (ii) downstream from PKC, activation of NFkappaB is essential while ERK1/2 MAP kinases, even though activated by Tat, are not directly involved in the pathway signaling leading to TNF-alpha production.     

Mu-opioid modulation of HIV-1 coreceptor expression and HIV-1 replication

A substantial proportion of HIV-1-infected individuals are intravenous drug users (i.v.DUs) who abuse opiates. Opioids induce a number of immunomodulatory effects that may directly influence HIV-1 disease progression. In the present report, we have investigated the effect of opioids on the expression of the major HIV-1 coreceptors CXCR4 and CCR5. For these studies we have focused on opiates which are ligands for the mu-opioid receptor. Our results show that DAMGO, a selective mu-opioid agonist, increases CXCR4 and CCR5 expression in both CD3(+) lymphoblasts and CD14(+) monocytes three- to fivefold. Furthermore, DAMGO-induced elevation of HIV-1 coreceptor expression translates into enhanced replication of both X4 and R5 viral strains of HIV-1. We have confirmed the role of the mu-opioid receptor based on the ability of a mu-opioid receptor-selective antagonist to block the effects of DAMGO. We have also found that morphine enhances CXCR4 and CCR5 expression and subsequently increases both X4 and R5 HIV-1 infection. We suggest that the capacity of mu-opioids to increase HIV-1 coreceptor expression and replication may promote viral binding, trafficking of HIV-1-infected cells, and enhanced disease progression.