Induced recruitment of NK cells to lymph nodes provides IFN-gamma for T(H)1 priming

Naive T cells are stimulated by antigen-presenting dendritic cells (DCs) in secondary lymphoid organs, but whether other types of cell participate in T cell priming is unclear. Here we show in mice that natural killer (NK) cells, which are normally excluded from lymph nodes, are rapidly recruited in a CCR7-independent, CXCR3-dependent manner to lymph nodes on stimulation by the injection of mature DCs. Recruitment of NK cells is also induced by some, but not all, adjuvants and correlates with the induction of T helper cell type 1 (T(H)1) responses. NK cell depletion and reconstitution experiments show that NK cells provide an early source of interferon-gamma (IFN-gamma) that is necessary for T(H)1 polarization. Taken together, our results identify an induced pathway of NK cell migration in antigen-stimulated lymph nodes and a mechanism by which some adjuvants may facilitate T(H)1 responses.     

Genetic linkage analysis identifies new proximal and distal flanking markers for the X-linked agammaglobulinemia gene locus, refining its localization in Xq22

Genetic linkage analysis has been instrumental in mapping thegene for X-linked agammaglobulinemia (XLA) to the proximal longarm of the human X chromosome, to Xq22. Due to the relativerarity of this disease the localization of the gene within Xq22has remained imprecise. We have investigated twenty-nine familiesaffected by XLA and have found no recombinants with the DXS178locus in over 30 informative meioses. DXS178 is now the mostreliable and informative locus for use in pre-natal diagnosisand carrier detection of XLA. In addition, we have identifiednew closely linked proximal and distal flanking markers forXLA, DXS442 and DXS101, respectively. These loci are separatedby 2cM, considerably reducing the extent of DNA within whichthe XLA locus can be contained. This will open up the way formore directed positional cloning efforts for the isolation ofthe XLA gene.     

TH1 and TH2 cytokine mRNA and protein levels in human immunodeficiency virus (HIV)-seropositive and HIV-seronegative youths

The roles of cytokines in the progression of human immunodeficiency virus (HIV)-associated disease are controversial. The patterns of innate cytokine production have been postulated to shift from TH1- to TH2-type cytokines with the progression of HIV-associated disease. Although there have been studies of cytokines in children and adults, no data are available on cytokine production in healthy or HIV-infected adolescents. We analyzed and characterized cytokine mRNA and protein levels for gamma interferon, interleukin 2 (IL-2), IL-4, and tumor necrosis factor alpha and protein levels of IL-6 in both stimulated and unstimulated peripheral blood mononuclear cells obtained from a large longitudinal, observational cohort study of HIV-seropositive and -seronegative adolescents. We correlated cytokine results with viral load and CD4(+)-T-cell counts as critical markers of disease progression in HIV-infected adolescents. These data were used to examine hypotheses related to the TH1-to-TH2 cytokine shift in a sample of HIV-infected adolescents. Five hundred twenty subjects participating in the REACH (Reaching for Excellence in Adolescent Care and Health) Project of the Adolescent Medicine HIV/AIDS Research Network contributed blood samples. Samples selected for the cross-sectional data set analyzed had to meet selection criteria developed to minimize the potential confounding effects of acute intercurrent illnesses or infections, recent vaccination for hepatitis, and altered hormone status and to optimize congruence of cytokine measurements with assays of viral load and CD4(+)-T-cell counts. Group differences in the proportions of subjects with detectable levels of each cytokine marker were compared. In the subset of subjects with detectable cytokine values, differences in detected values were compared across subgroups defined by HIV serostatus and among HIV-seropositive subjects by three viral load classifications. The study sample was 65% HIV seropositive, 71% African-American, and 75% female with a mean age of 17.4 years. HIV-seropositive subjects were relatively healthy with mean and median CD4(+)-T-cell counts of 534 and 499 cells/mm(3), respectively. Only 8.1% of subjects had CD4(+)-T-cell counts below 200 cells/mm(3), and 25% had viral loads that were below the threshold of detection (<400 copies/ml). Detailed analyses of these data indicate that there were no differences in cytokines detected in HIV-seropositive and HIV-seronegative adolescents, and there was no apparent relationship between the cytokine measurements and the viral load or CD4(+)-T-cell categorization, the parameters selected as markers of HIV-associated disease status. These adolescents, including the HIV-seropositive subjects, were relatively healthy, and the HIV-infected subjects were at an early stage in the course of their HIV-associated disease. On the basis of our data, we conclude that, early in the course of HIV-associated disease in adolescents, there are no detectable shifts from TH1 to TH2 cytokine production.     

Role of Elastin in Spontaneously Hypertensive Rat Small Mesenteric Artery Remodelling

Chronic hypertension is associated with resistance artery remodelling and mechanical alterations. However, the contribution of elastin has not been thoroughly studied. Our objective was to evaluate the role of elastin in vascular remodelling of mesenteric resistance arteries (MRA) from spontaneously hypertensive rats (SHR). MRA segments from Wistar Kyoto rats (WKY) and SHR were pressurised under passive conditions at a range of physiological pressures with pressure myography. Confocal microscopy was used to determine differences in the quantity and organisation of elastin in intact pressure-fixed arteries. To assess the contribution of elastin to MRA structure and mechanics, myograph-mounted vessels were studied before and after elastase incubation. When compared with WKY, MRA from SHR showed: (1) a smaller lumen, (2) decreased distensibility at low pressures, (3) a leftward shift of the stress-strain relationship, (4) redistribution of elastin within the internal elastic lamina (IEL) leading to smaller fenestrae but no change in fenestrae number or elastin amount. Elastase incubation (1) fragmented the structure of IEL in a concentration-dependent fashion, (2) abolished all the structural and mechanical differences between strains, and (3) decreased distensibility at low pressures. The study shows the overriding role of elastin in determining vascular dimensions and mechanical properties in a resistance artery. In addition, it informs hypertensive remodelling. MRA remodelling and increased stiffness are accompanied by elastin restructuring within the IEL and elastin degradation reverses structural and mechanical alterations of SHR MRA. Differences in elastin organisation are, therefore, a central element in small artery remodelling in hypertension.     

Sequence variation and size ranges of CAG repeats in the Machado-Joseph disease, spinocerebellar ataxia type 1 and androgen receptor genes

A subgroup of trinucleotide repeat diseases result from abnormalexpansions of CAG repeats which are translated into polyglutaminestretches. As yet there is little understanding of how the polyglutaminesfunction either normally, or when expanded. We have investigatedthese sequences in the Machado-Joseph disease, androgen receptorand spinocerebellar ataxia type 1 genes in humans and otherprimates. None of the 748 normal chromosomes that were examinedhad more than 34 uninterrupted gluta-mine codons in the Machado-Josephdisease gene. Similarly, no normal alleles with more than 39uninterrupted glutamine codons have been reported for the otherdisease genes associated with polyglutamine expansions. Sequenceanalyses of the repeats in primates revealed shorter polyglutaminestretches in some of the non-human primates at all three lociand marked diversions from the expected polyglutamines in theorang-utan Machado-Joseph gene and in the marmoset spinocerebellarataxia type 1 gene. These data suggest that conservation ofthese polyglutamine stretches may not always be necessary fornormal gene function.     

No association between the -308 polymorphism in the tumour necrosis factor alpha (TNFalpha) promoter region and polycystic ovaries

The tumour necrosis factor (TNF)2 allele appears to be linked with increased insulin resistance and obesity, conditions often found in overweight patients with polycystic ovary syndrome (PCOS). The significance of TNFalpha polymorphism in relation to the clinical and biochemical parameters associated with PCOS was investigated in 122 well-characterized patients with polycystic ovaries (PCO). Of these, 84 had an abnormal menstrual cycle and were classified as having PCOS, while the remaining 38 had a normal menstrual cycle and were classified as having PCO. There were a further 28 individuals without PCO (non-PCO) and 108 individuals whose PCO status was undetermined (reference population). The promoter region of the TNFalpha gene was amplified by polymerase chain reaction (PCR), and the presence or absence of the polymorphism at -308 was determined by single-strand conformational polymorphism (SSCP) analysis. The less common TNF allele (TNF2) was found as TNF1/2 or TNF2/2 in 11/38 (29%) of PCO subjects, 25/84 (30%) of PCOS subjects, 7/28 (25%) of non-PCO subjects, and 45/108 (42%) of the reference population. There was no significant difference in the incidence of the TNF2 allele between the groups. The relationship of TNF genotype to clinical and biochemical parameters was examined. In both the PCO group and the PCOS group, the presence of the TNF2 allele was significantly associated with lower glucose values obtained from the glucose tolerance testing (P<0.05). The TNF genotype was not significantly associated with any clinical or biochemical parameter measured in the PCO, PCOS or non-PCOS groups. Thus, the TNFalpha -308 polymorphism does not appear to strongly influence genetic susceptibility to polycystic ovaries.