Induction of SerpinB2 and Th1/Th2 Modulation by SerpinB2 during Lentiviral Infections In Vivo

SerpinB2, also known as plasminogen activator inhibitor type 2, is a major product of activated monocytes/macrophages and is often strongly induced during infection and inflammation; however, its physiological function remains somewhat elusive. Herein we show that SerpinB2 is induced in peripheral blood mononuclear cells following infection of pigtail macaques with CCR5-utilizing (macrophage-tropic) SIV_mac239, but not the rapidly pathogenic CXCR4-utilizing (T cell-tropic) SHIV_mn229. To investigate the role of SerpinB2 in lentiviral infections, SerpinB2^−/− mice were infected with EcoHIV, a chimeric HIV in which HIV gp120 has been replaced with gp80 from ecotropic murine leukemia virus. EcoHIV infected SerpinB2^−/− mice produced significantly lower anti-gag IgG1 antibody titres than infected SerpinB2^+/+ mice, and showed slightly delayed clearance of EcoHIV. Analyses of published microarray studies showed significantly higher levels of SerpinB2 mRNA in monocytes from HIV-1 infected patients when compared with uninfected controls, as well as a significant negative correlation between SerpinB2 and T-bet mRNA levels in peripheral blood mononuclear cells. These data illustrate that SerpinB2 can be induced by lentiviral infection in vivo and support the emerging notion that a physiological role of SerpinB2 is modulation of Th1/Th2 responses.     

Opposite effects of cholecystokinin octapeptide (CCK-8) and tetrapeptide (CCK-4) after injection into the caudal part of the nucleus accumbens or into its rostral part and the cerebral ventricles

Neurons with colocalized cholecystokinin and dopamine are present predominantly in the ventral tegmental area and project mainly to the caudal part of the medial nucleus accumbens. The activity of this dopamine system can be evaluated by means of the intracranial self-stimulation behavior on male Wistar rats having chronic electrodes implanted into the medial forebrain bundle in the postero-lateral area of the hypothalamus. The direct injection of 150 pmol CCK-8 into the medio-caudal accumbens induced an increase of intracranial self stimulation while a similar administration into its rostral portion produced a slight decrease of intracranial self-stimulation. The administration of 300 pmol CCK-4 into the same medio-caudal part of the accumbens produced an inhibitory action on intracranial self stimulation lasting for 25 min. The injection of 70 to 1300 pmol CCK-4 into the cerebral ventricles produced no change on intracranial self-stimulation. The intracerebroventricular injection of 70 pmol CCK-8 induced a large decrease of intracranial self-stimulation lasting for 20 min. Sodium chloride 0.15 M or unsulphated CCK-8 injection were without effect in either case. These results support the ideas that intracerebroventricular CCK-8 injection inhibits accumbens dopaminergic activity but that CCK-8 injection into the medio-caudal part of the accumbens, where nerve terminals with colocalized CCK and DA are present, facilitates this dopaminergic activity. In addition at the level of medio-caudal accumbens, CCK-8 and CCK-4 have opposite effects.     

Lack of dendritic Thy-1+ epidermal cells in mice with severe combined immunodeficiency disease

C.B-17 scid (severe combined immunodeficiency disease) mice were used to evaluate the relationship of dendritic Thy-1+ epidermal cells (EC) to T lymphocytes (deficient in scid) and to NK cells (replete in scid). Epidermis from scid mice was deficient in dendritic Thy-1+ cells as determined by immunofluorescent staining of epidermal whole mounts. Similarly, epidermal cell suspensions from scid mice failed to proliferate in response to Con A, as compared with epidermal cell suspensions from C.B-17 control mice. Transplantation of normal bone marrow into scid mice reconstituted morphologically identifiable dendritic Thy-1+ EC in whole mounts, as well as Con A responsiveness of EC suspensions, thus indicating that the deficiency in dendritic Thy-1+ EC in scid mice is at the precursor level. These studies demonstrate that Thy-1+ EC are more closely related to T lymphocytes than to NK cells.     

Characterization of B lymphocyte lineage progenitor cells from mice with severe combined immune deficiency disease (SCID) made possible by long term culture

A single gene mutation results in near absence of B and T lymphocytes and their immediate progenitors in mice with severe combined immunodeficiency disease (SCID). However, long term culture conditions allowed rapid outgrowth of lymphocytes from SCID bone marrow suspensions, and this permitted their detailed analysis. The cells were judged to be committed to the B lymphocyte lineage on the basis of expression of the BP-1 antigen, as well as by the density and pattern of expression of other markers. Cultured SCID lymphocytes were indistinguishable from control BALB/c cells in terms of morphology, typing for 13 cell surface markers, and changes in cell surface antigen expression with time in culture. In contrast to cultures of normal cells, which always included IgM synthesizing cells, SCID lymphocytes rarely expressed mu heavy chains. Southern blot analysis demonstrated that at least the first Ig gene rearrangement step had occurred in most of the cultured cells. The patterns of JH gene rearrangements suggested that relatively limited population diversity existed in individual cultures of SCID and normal BALB/c marrow. In addition, there was evidence that abnormal Ig heavy chain gene rearrangements had taken place in lymphocytes from approximately 25% of the SCID cultures. These cells were distinguished by the absence of detectable JH gene segments. kappa light chain genes appeared to be unrearranged in SCID cultured lymphocytes. We conclude that the lymphopoietic microenvironments of SCID mice are probably normal, and the animals have infrequent progenitors of B cells. Aberrant or nonproductive IgH gene rearrangements may account for the absence of pre-B and B cells in SCID mice. This study demonstrates the usefulness of long term culture methodology for isolating rare subsets of non-transformed lymphoid cells from normal and genetically defective hemopoietic tissues.     

Metabolism and excretion of acetylchromenes by the migratory grasshopper

The extent of metabolism and excretion of three acetylchromenes (two toxic, one relatively nontoxic) were examined in adult migratory grasshoppers (Melanoplus sanguinipes) following topical administration. Both the total amount excreted (parent plus metabolites) and the proportion of parent compound in the excreta were inversely correlated with contact toxicity. Both toxic and nontoxic acetylchromenes are rapidly absorbed from the cuticle, with maximum excretion of parent and metabolite chromenes from 4 to 8 h posttreatment in each case. Much of the applied compounds (60–80%) apparently remains within the insect, and cannot be recovered by extraction of the insect. Metabolites formed result from simple oxidative and reductive transformations. For all of the compounds tested (including the allatocidin precocene II), the major mode of metabolism results from aliphatic hydroxylation of one of the geminal methyl groups on the chromene. No conjugated metabolites were found in the excreta.