Low-dose IL-2 induces CD56bright NK regulation of T cells via NKp44 and NKp46.

Low-dose interleukin (IL)-2 has shown clinical benefits in patients with autoimmune and inflammatory diseases. Both regulatory T cells (Tregs ) and natural killer (NK) cells are increased in response to low-dose IL-2 immunotherapy. The role of regulatory T cells in autoimmune diseases has been extensively studied; however, NK cells have not been as thoroughly explored. It has not been well reported whether the increase in NK cells is purely an epiphenomenon or carries actual benefits for patients with autoimmune diseases. We demonstrate that low-dose IL-2 expands the primary human CD56bright NK cells resulting in a contact-dependent cell cycle arrest of effector T cells (Teffs ) via retention of the cycle inhibitor p21. We further show that NK cells respond via IL-2R-ß, which has been shown to be significant for immunity by regulating T cell expansion. Moreover, we demonstrate that blocking NK receptors NKp44 and NKp46 but not NKp30 could abrogate the regulation of proliferation associated with low-dose IL-2. The increase in NK cells was also accompanied by an increase in Treg cells, which is dependent on the presence of CD56bright NK cells. These results not only heighten the importance of NK cells in low-dose IL-2 therapy but also identify key human NK targets, which may provide further insights into the therapeutic mechanisms of low-dose IL-2 in autoimmunity.

A factor IX gene probe: its use in carrier detection, antenatal diagnosis and characterisation of the molecular basis for hemophilia B.

Of hemophilia B carriers, 67% were shown to have informative restriction fragment length polymorphisms (Taq I or Xmn I) associated with the factor IX gene. Analysis of DNA for these polymorphisms can enable the detection of the hemophilia B carrier state in females and of hemophilia B in the male fetus in the first trimester. Extensive mapping of the factor IX gene in one hemophiliac who developed antibodies to factor IX failed to detect structural abnormalities in his gene. A non-deletional basis for hemophilia B is proposed in this instance.

Mechanism and contribution of the pentose phosphate cycle to glucose metabolism in epididymal fat tissue.

1. Glucose 6-phosphate, fructose 6-phosphate and altroheptulose 7-phosphate are the major products formed non-oxidatively from ribose 5-phosphate by rat epididymal fat pad enzymes. 2. Arabinose 5-phosphate was detected among the reaction products and significant activity of the new enzyme of the L-type pentose pathway, D-glycero D-ido octulose 1,8-bisphosphate: D-altroheptulose 7-phosphotransferase was found. 3. The glucose moieties of glucose 1-phosphate, glucose 6-phosphate and glucose 1,6-bisphosphate were degraded and showed that epididymal fat pad enzymes relocate 14C from [2-14C]glucose into C-1, C-2, and C-3 of each hexose-phosphate. 4. The 14C-distribution patterns in the hexose-phosphates revealed that these intermediates were not in isotopic equilibrium and the rate of the transaldolase exchange reaction was relatively small. 5. The 14C-distribution data suggest that glucose 1-phosphate, rather than glucose 6-phosphate, is the first intermediate in the path of glycogen synthesis from glucose in this tissue. 6. The data provide the first proof of the mechanism of the pentose pathway in adipose tissue.