Surfactant protein D modulates HIV infection of both T-cells and dendritic cells

Surfactant Protein D (SP-D) is an oligomerized C-type lectin molecule with immunomodulatory properties and involvement in lung surfactant homeostasis in the respiratory tract. SP-D binds to the enveloped viruses, influenza A virus and respiratory syncytial virus and inhibits their replication in vitro and in vivo. SP-D has been shown to bind to HIV via the HIV envelope protein gp120 and inhibit infectivity in vitro. Here we show that SP-D binds to different strains of HIV (BaL and IIIB) and the binding occurs at both pH 7.4 and 5.0 resembling physiological relevant pH values found in the body and the female urogenital tract, respectively. The binding of SP-D to HIV particles and gp120 was inhibited by the presence of several hexoses with mannose found to be the strongest inhibitor. Competition studies showed that soluble CD4 and CVN did not interfere with the interaction between SP-D and gp120. However, soluble recombinant DC-SIGN was shown to inhibit the binding between SP-D and gp120. SP-D agglutinated HIV and gp120 in a calcium dependent manner. SP-D inhibited the infectivity of HIV strains at both pH values of 7.4 and 5.0 in a concentration dependent manner. The inhibition of the infectivity was abolished by the presence of mannose. SP-D enhanced the binding of HIV to immature monocyte derived dendritic cells (iMDDCs) and was also found to enhance HIV capture and transfer to the T-cell like line PM1. These results suggest that SP-D can bind to and inhibit direct infection of T-cells by HIV but also enhance the transfer of infectious HIV particles from DCs to T-cells in vivo

Reductions in circulating levels of IL-16, IL-7 and VEGF-A in myalgic encephalomyelitis/chronic fatigue syndrome

Recently, differences in the levels of various chemokines and cytokines were reported in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as compared with controls. Moreover, the analyte profile differed between chronic ME/CFS patients of long duration versus patients with disease of less than 3 years. In the current study, we measured the plasma levels of 34 cytokines, chemokines and growth factors in 100 chronic ME/CFS patients of long duration and in 79 gender and age-matched controls. We observed highly significant reductions in the concentration of circulating interleukin (IL)-16, IL-7, and Vascular Endothelial Growth Factor A (VEGF-A) in ME/CFS patients. All three biomarkers were significantly correlated in a multivariate cluster analysis. In addition, we identified significant reductions in the concentrations of fractalkine (CX3CL1) and monokine-induced-by-IFN-γ (MIG; CXCL9) along with increases in the concentrations of eotaxin 2 (CCL24) in ME/CFS patients. Our data recapitulates previous data from another USA ME/CFS cohort in which circulating levels of IL-7 were reduced. Also, a reduced level of VEGF-A was reported previously in sera of patients with Gulf War Illness as well as in cerebral spinal fluid samples from a different cohort of USA ME/CFS patients. To our knowledge, we are the first to test for levels of IL-16 in ME/CFS patients. In combination with previous data, our work suggests that the clustered reduction of IL-7, IL-16 and VEGF-A may have physiological relevance to ME/CFS disease. This profile is ME/CFS-specific since measurement of the same analytes present in chronic infectious and autoimmune liver diseases, where persistent fatigue is also a major symptom, failed to demonstrate the same changes. Further studies of other ME/CFS and overlapping disease cohorts are warranted in future

HIV-1 assembly in macrophages

The molecular mechanisms involved in the assembly of newly synthesized Human Immunodeficiency Virus (HIV) particles are poorly understood. Most of the work on HIV-1 assembly has been performed in T cells in which viral particle budding and assembly take place at the plasma membrane. In contrast, few studies have been performed on macrophages, the other major target of HIV-1. Infected macrophages represent a viral reservoir and probably play a key role in HIV-1 physiopathology. Indeed macrophages retain infectious particles for long periods of time, keeping them protected from anti-viral immune response or drug treatments. Here, we present an overview of what is known about HIV-1 assembly in macrophages as compared to T lymphocytes or cell lines

Acid sensitivity of cell-free and cell-associated HIV-1: Clinical implications

Infectivity of free and cell-associated human immunodeficiency virus type 1 (HIV-1) treated in vitro at pH 7.4 to 4.9 for 2 hours was assessed on susceptible CEM-ss cells. Viral activity was monitored by cytopathology and production of reverse transcriptase and p24 antigen. The infectivity of cell-free virus was gradually inactivated and at pH 5.4 was completely lost, with or without subsequent adjustment of pH to neutral. Virus-producing cells also gradually lost their ability to infect as the pH decreased; however, restoration of neutral pH resulted in regained infectivity. Since the pH values used in the study are similar to those found at various entry sites of the human body, the data may be relevant to the mode of transmittal of HI

Human Herpesvirus 6 variant A enanches in vitro HIV-1 replication by soluble mediators, which effect is diminisched by endotoxin

Simultaneous HHV-6A infection can activate HIV-1 latency and promote AIDS progression, but in this process the effects of HHV-6A induced soluble mediators on HIV-1 have not been studied yet. Recently, supernatants of HSB-2 cultures infected with HHV-6A and/or treated with endotoxin have been filtered virus free at time intervals until the cytopathic effect developed. Biological activity of some cytokines which might participate in HIV-1 activation was quantitated. Filtered supernatants were mixed into CEM-ss cultures, which had been HIV-1 infected at 1:1 cell:virus ratio, subsequently HIV-1 replication was quantitated and compared to controls. Supernatants filtered during the first 96 hours of HHV-6A replication without visible cytopathic effect augmented HIV-1 syncytium formation by tenfold, reverse transcriptase activity by threefold, p24 antigen production by 6-fold. Filtered supernatants obtained at onset of HHV-6A cytopathic effect did not modify HIV-1 replication. HSB-2 cultures produced no IL-2, and IFN-gamma induced by endotoxin diminished HIV-1 replication. HHV-6A delayed IFN-gamma release. An increase in the tumour necrosis factor activity upon the effect of HHV-6A and endotoxin was not parallel to HIV-1 activation. The putative mediator, different from those above which characterisation is in progress, might transmit similar transactivating effects between immune cells of lymph nodes and circulatio

Az emberi 6-os herpeszvirus A valozata szolubilis mediatorok àaltal fokozza a HIV-1 szaporodàsàt in vitro, mely hàtast az endotoxin csokkenti = Human herpesvirus 6 variant A enhances in vitro HIV-1 replication by soluble mediators, the effect of which is diminished by indotoxin

Simultaneous HHV-6A infection can activate HIV-1 latency and promote AIDS progression, but in this process the effects of HHV-6A induced soluble mediators on HIV-1 have not been studied yet. Recently, supernatants of HSB-2 cultures infected with HHV-6A and/or treated with endotoxin have been filtered virus free at time intervals until the cytopathic effect developed. Biological activity of some cytokines which might participate in HIV-1 activation was quantitated. Filtered supernatants were mixed into CEM-ss cultures, which had been HIV-1 infected at 1:1 cell:virus ratio, subsequently HIV-1 replication was quantitated and compared to controls. Supernatants filtered during the first 96 hours of HHV-6A replication without visible cytopathic effect augmented HIV-1 syncytium formation by tenfold, reverse transcriptase activity by threefold, p24 antigen production by 6-fold. Filtered supernatants obtained at onset of HHV-6A cytopathic effect did not modify HIV-1 replication. HSB-2 cultures produced no IL-2, and IFN-gamma induced by endotoxin diminished HIV-1 replication. HHV-6A delayed IFN-gamma release. An increase in the tumour necrosis factor activity upon the effect of HHV-6A and endotoxin was not parallel to HIV-1 activation. The putative mediator, different from those above which characterisation is in progress, might transmit similar transactivating effects between immune cells of lymph nodes and circulation