The regulated secretory pathway in CD4(+) T cells contributes to human immunodeficiency virus type-1 cell-to-cell spread at the virological synapse.

Direct cell-cell spread of Human Immunodeficiency Virus type-1 (HIV-1) at the virological synapse (VS) is an efficient mode of dissemination between CD4(+) T cells but the mechanisms by which HIV-1 proteins are directed towards intercellular contacts is unclear. We have used confocal microscopy and electron tomography coupled with functional virology and cell biology of primary CD4(+) T cells from normal individuals and patients with Chediak-Higashi Syndrome and report that the HIV-1 VS displays a regulated secretion phenotype that shares features with polarized secretion at the T cell immunological synapse (IS). Cell-cell contact at the VS re-orientates the microtubule organizing center (MTOC) and organelles within the HIV-1-infected T cell towards the engaged target T cell, concomitant with polarization of viral proteins. Directed secretion of proteins at the T cell IS requires specialized organelles termed secretory lysosomes (SL) and we show that the HIV-1 envelope glycoprotein (Env) localizes with CTLA-4 and FasL in SL-related compartments and at the VS. Finally, CD4(+) T cells that are disabled for regulated secretion are less able to support productive cell-to-cell HIV-1 spread. We propose that HIV-1 hijacks the regulated secretory pathway of CD4(+) T cells to enhance its dissemination.

Interleukin-1 cluster combined genotype and restenosis after balloon angioplasty.

The interleukin-1 system is fundamentally involved in the pathogenesis of restenosis after percutaneous transluminal angioplasty (PTA). In order to further define the clinical impact of genetic variation in this potent proinflammatory pathway we investigated the joint effects of two single nucleotide polymorphisms in the interleukin-1 beta gene [IL-1B(-511) and IL-1B(+3954)] and a variable number tandem repeat polymorphism in intron 2 of the interleukin 1 receptor antagonist gene (IL-1RN VNTR) on postintervention inflammation and occurrence of restenosis in 183 consecutive patients who underwent successful femoropopliteal PTA. C-reactive protein (CRP) and serum amyloid A (SAA) were determined pre- and 48 hours postintervention. Patients were followed up to 12 months for the occurrence of postangioplasty restenosis (> or = 50%). When analyzed separately, none of the polymorphisms was associated either with inflammation or restenosis. However, when the IL-1B (-511) and the IL-1RN VNTR genotypes were combined, a highly significant relationship was observed: Non-carriers of the two repeat allele of the IL-1RN VNTR (IL-1RN*2) who were heterozygous and homozygous for the IL-1B (-511)T allele exhibited a gradually increased inflammatory response and a higher restenosis risk. In contrast, carriers of the IL-1RN*2 and the IL-1B (-511)T allele showed a significantly better outcome. This remarkable gene dose-dependent association emphasizes the advantage of considering combinations of genetic markers rather that isolated polymorphisms in the analysis of multifactorial vascular disease.