Elevated plasma stromal cell-derived factor 1 protein level in the progression of HIV type 1 infection/AIDS

Stromal cell-derived factor 1 (SDF-1) is a unique chemokine involved in multiple organogenesis as well as in the regulation of HIV infection. Here we determined the plasma SDF-1 concentrations of 193 HIV-1-infected individuals and 154 normal Japanese volunteers by developing a highly sensitive measurement system based on time-resolved fluoroimmunoassay (SDF-1 TR-FIA). This system is also valid for the mouse model to quantitate circulating SDF-1 concentration in vivo and thereby its correlation with CXCR4 expression level on CD4(+) T cells. Interestingly, plasma SDF-1 concentrations in HIV-1-infected individuals were three times higher than those in a normal control group and plasma SDF-1 protein levels showed an inverse correlation with CD4(+) T cell count and a positive correlation with plasma HIV-1 RNA load. Notably, individuals with later stage HIV-1 infection, who maintained fewer than 200 CD4(+) T cells per cubic milliliter and more than 10,000 copies of HIV-1 RNA per milliliter, showed the highest plasma SDF-1 level among individuals at any stage of HIV-1 infection. These results suggest that endogenous SDF-1 is upregulated by HIV-1 infection, particularly in late-stage HIV-1 infection/AIDS.

[Anti-HIV-1 genes; genetic restriction of AIDS pathogenesis by gene variants]

Three genes which have variants acting as anti-HIV-1 were described so far. Among three, two are genes encoding receptors for chemokines, namely CCR5 and CCR2, which act as entry coreceptors for HIV-1 virus. The other gene is SDF1 gene. SDF-1, a cytokine belonging to the chemokine family has an inhibitory activity against the HIV-1 infection, because SDF-1 Is the physiological ligand for CXCR4, the entry coreceptor for T tropic HIV-1 virus. Recently, an SDF1 gene polymorphism was figured out to be one of the human genetic factors which regulate the period between the HIV-1 infection and the AIDS onset. By this finding, it was strongly suggested that SDF-1 regulates the onset of AIDS in the actual human population.

Anti-HIV-1 and chemotactic activities of human stromal cell-derived factor 1alpha (SDF-1alpha) and SDF-1beta are abolished by CD26/dipeptidyl peptidase IV-mediated cleavage

CD26 is a leukocyte-activation antigen that is expressed on T lymphocytes and macrophages and possesses dipeptidyl peptidase IV (DPPIV) activity, whose natural substrates have not been identified yet. CXC chemokines, stromal cell-derived factor 1alpha (SDF-1alpha) and 1beta (SDF-1beta), sharing the receptor CXCR-4, are highly efficacious chemoattractants for resting lymphocytes and CD34(+) progenitor cells, and they efficiently block the CXCR-4-mediated entry into cells of T cell line tropic strains of HIV type 1 (HIV-1). Here we show that both the chemotactic and antiviral activities of these chemokines are abrogated by DPPIV-mediated specific removal of the N-terminal dipeptide, not only when the chemokines are produced in transformed mouse L cell line to express human CD26 but also when they were exposed to a human T cell line (H9) physiologically expressing CD26. Mutagenesis of SDF-1alpha confirmed the critical requirement of the N-terminal dipeptide for its chemotactic and antiviral activities. These data suggest that CD26-mediated cleavage of SDF-1alpha and SDF-1beta likely occurs in human bodies and promotes HIV-1 replication and disease progression. They may also explain why memory function of CD4(+) cells is preferentially lost in HIV-1 infection. Furthermore, CD26 would modulate various other biological processes in which SDF-1alpha and SDF-1beta are involved.

Psychological studies of a Japanese winter-over group at Asuka Station, Antarctica

In order to understand the psychological effects of Antarctic isolation and confinement on Japanese expeditioners, psychological studies were done on eight members of a wintering-over party at Asuka Station between December 1990 and February 1992. Mean age of the subjects was 34.8 +/- 5.56 yr. The study includes self assessment questionnaires, psychological tests introduced by the Polar Psychology Project (PPP), a bibliographical study and photographic measurements. There was no pathological depression in midwinter. Subjective and cumulative fatigue symptoms were more noticeable in the older individuals. The Telic Dominance Scale was significantly correlated with the Anxiety Sensitivity Index. The Sense of Coherence Inventory and the Personal View Survey showed an interrating correlation. By analyzing a daily group photograph, seasonal variations in mood and behavior of individuals have been clarified. Consequently, it is hoped that observation of non-verbal signals such as facial expression, clothing, and postures may lead to the development of a new methodological framework for the long-term plan of psychological investigation of the men under severe stress.

Large quantity production with extreme convenience of human SDF-1alpha and SDF-1beta by a Sendai virus vector

We describe a robust expression of human stromal cell-derived factor-1alpha (SDF-1alpha) and SDF-1beta, the members of CXC-chemokine family, with a novel vector system based upon Sendai virus, a non-segmented negative strand RNA virus. Recombinant SDF-1alpha and SDF-1beta were detected as a major protein species in culture supernatants, reached as high as 10 microg/ ml. This remarkable enrichment of the products allowed us to use even the crude supernatants as the source for biological and antiviral assays without further concentration nor purification and will thus greatly facilitate to screen their genetically engineered derivatives.

Springtime peaks of trace metals in Antarctic snow

Drifting snow samples were collected at Asuka Station (71 degrees 32'S, 24 degrees 08'E, 930 m above sea level) over a period from July to December 1991; 36 elements (including Na, Mg, K, Ca, Fe, Al, Li, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Se, Rb, Sr, Cd, Pb, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th) in snow were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) by direct sample introduction. Concentrations of Cl-, NO3-, and SO(4)2- in the snow were also determined by ion chromatography. In late September to early October, there was a pronounced peak concentration of most of the elements together with non-sea salt sulfate. Enrichment factor analyses suggest that Na, Mg, Ca, K, and Sr are of marine origin and Al, Fe, Mn, Rb, Cr, Ni, Ga, V, and all the rare earth elements are of crustal origins. Volcanic eruption of Mt. Pinatubo (June 1991) and Mt. Hudson (August 1991) could be the reason for the precipitation of Pb, Cd, Cu, Zn, and Se together with non-sea salt sulfates in the austral spring at Asuka Station.