Mice lacking interleukin-2 (IL-2)/IL-15 receptor beta chain are susceptible to infection with avirulent Salmonella enterica subsp. enterica serovar choleraesuis but mice lacking IL-2 are resistant.

Interleukin-2 (IL-2)/IL-15 receptor beta (IL-15R beta)(-/-) mice were susceptible to infection with avirulent Salmonella enterica subsp. enterica serovar Choleraesuis, whereas IL-2(-/-) mice were resistant. A natural killer cell response was not evident for both types of deficient mice. A Th1 response was detected in IL-2(-/-) but not in IL-2/IL-15R beta(-/-) mice infected with Salmonella, suggesting that IL-2/IL-15R beta signaling is important for the generation of protective Th1 cells.

A protective role of interleukin-15 in a mouse model for systemic infection with herpes simplex virus.

To define the role of cytokine binding to the IL-2/IL-15R beta chain in protective immunity against systemic infection with herpes simplex virus type 2 (HSV-2), IL-2/IL-15 receptor(R)beta knock-out mice were inoculated intraperitoneally with HSV-2 strain 186. IL-2/IL-15R beta-deficient mice were susceptible to systemic HSV-2 infection compared with their heterozygous littermates. The emergence of natural killer (NK) cells was impaired in IL-2/IL-15R beta knock-out mice, but CD4(+) T cell receptor (TCR) alpha beta(+) T cells were normally detected in the peritoneal cavity after infection with HSV-2. However, the generation of HSV-2-specific CD4(+) T helper (Th) 1 cells producing interferon-gamma was impaired in IL-2/IL-15R beta knock-out mice following HSV-2 infection. The serum IL-15 level in control mice was increased in the early stage after HSV-2 infection but was not detectable in IL-2/IL-15R beta knock-out mice. In vivo administration of recombinant IL-15 protected normal mice from HSV-2-induced lethality, accompanied by increases in numbers of NK cells and HSV-2-specific Th1 cells. Taken together, these results suggest that IL-15, using the IL-2/IL15R beta chain, plays an important role in mounting protective immunity during the course of systemic HSV-2 infection.

Memory-type CD8+ T cells protect IL-2 receptor alpha-deficient mice from systemic infection with herpes simplex virus type 2.

IL-2Ralpha-deficient (IL-2Ralpha(-/-)) mice exhibit an impaired activation-induced cell death for T cells and develop abnormal T cell activation with age. In our study, we found that IL-2Ralpha(-/-) mice at the age of 5 wk contained an increased number of CD44(+)CD69(-)CD8(+) T cells in lymph nodes, which expressed a high intensity of IL-2Rbeta and vigorously proliferated in response to a high dose of IL-15 or IL-2. The T cells produced a large amount of IFN-gamma in response to IL-15 plus IL-12 in a TCR-independent bystander manner. When IL-2Ralpha(-/-) mice were inoculated i.p. with HSV type 2 (HSV-2) 186 strain, they showed resistance to the infection accompanied by an increased level of serum IL-15. The depletion of CD8(+) T cells by in vivo administration of anti-CD8 mAb rendered IL-2Ralpha(-/-) mice susceptible to HSV-2-induced lethality. These results suggest that memory-type CD8(+) T cells play a novel role in the protection against HSV-2 infection in IL-2Ralpha(-/-) mice.

Differential roles of interleukin 15 mRNA isoforms generated by alternative splicing in immune responses in vivo.

At least two types of interleukin (IL)-15 mRNA isoforms are generated by alternative splicing at the 5' upstream of exon 5 in mice. To elucidate the potential roles of IL-15 isoforms in immune responses in vivo, we constructed two groups of transgenic mice using originally described IL-15 cDNA with a normal exon 5 (normal IL-15 transgenic [Tg] mice) and IL-15 cDNA with an alternative exon 5 (alternative IL-15 Tg mice) under the control of an MHC class I promoter. Normal IL-15 Tg mice constitutionally produced a significant level of IL-15 protein and had markedly increased numbers of memory type (CD44(high) Ly6C(+)) of CD8(+) T cells in the LN. These mice showed resistance to Salmonella infection accompanied by the enhanced interferon (IFN)-gamma production, but depletion of CD8(+) T cells exaggerated the bacterial growth, suggesting that the IL-15-dependent CD8(+) T cells with a memory phenotype may serve to protect against Salmonella infection in normal IL-15 Tg mice. On the other hand, a large amount of intracellular IL-15 protein was detected but hardly secreted extracellularly in alternative IL-15 Tg mice. Although most of the T cells developed normally in the alternative IL-15 Tg mice, they showed impaired IFN-gamma production upon TCR engagement. The alternative IL-15 transgenic mice were susceptible to Salmonella accompanied by impaired production of endogenous IL-15 and IFN-gamma. Thus, two groups of IL-15 Tg mice may provide information concerning the different roles of IL-15 isoforms in the immune system in vivo.

[The catecholamine concentrations of collected autologous blood during adrenalectomy for pheochromocytoma].

We studied the catecholamine concentrations in collected autologous blood of a patient undergoing adrenalectomy for pheochromocytoma. In the preoperative laboratory data, plasma concentrations (normal ranges) of epinephrine, norepinephrine and dopamine were 60180 pg.ml-1 (< 100), 11090 pg.ml-1 (100-450) and 104 pg.ml-1 (< 20), respectively. The catecholamine levels of collected blood were epinephrine 2490000 pg.ml-1, norepinephrine 352300 pg.ml-1 and dopamine 6100 pg.ml-1 before wash. Wash of collected blood with 1000 ml saline diluted the catecholamines to epinephrine 212000 pg.ml-1, norepinephrine 18700 pg.ml-1 and dopamine 4900 pg.ml-1. Platelet activation by contact with tissue collagen or thrombin results in the release of catecholamine concentrated in the dense body. The mechanical stimulation by suction, roller pump and centrifugation during blood collection may accelerate the catecholamine release from platelets. Thus, saline wash hardly reduces catecholamine concentrations of collected blood from a patient with pheochromocytoma. In this particular case, plasma catecholamines seem to exceed the potential capacity of platelets in amount. The dilution effect for epinephrine and norepinephrine probably reflects the washout of greater amount of plasma catecholamines. However, saline wash was unable to reduce catecholamines contained in the collected blood to a safe level, and hypertension following autotransfusion was predictable. We conclude that hemodynamic change should be monitored carefully during intraoperative autotransfusion in a case of pheochromocytoma.

Effects of ryanodine and nifedipine on contractions induced by norepinephrine, acetylcholine, and potassium in the isolated vas deferens of the guinea pig.

In the present study we tried to determine the relative contributions of sarcoplasmic reticulum (SR) calcium release and gated calcium entry through voltage-dependent calcium-channels (VDC) to the contractions induced by norepinephrine (NE, 10 microM) and acetylcholine (ACh, 10 microM) in the vas deferens of the guinea pig. NE and ACh at 10 microM caused contractions composed of three phases: a prephasic, a phasic and a tonic component. Nifedipine strongly inhibited the contractions induced by potassium (K, 100 mM) and abolished phasic components of the contractions induced by NE or ACh. However, the tonic components of NE- or ACh-induced contractions were slightly attenuated by nifedipine. Pretreatment with ryanodine in combination with caffeine attenuated prephasic and tonic components of the contractions induced by NE and ACh in a dose-dependent manner. The inhibitory effects of ryanodine and caffeine on the phasic component of NE-induced contractions were divided into two types: 1) abolishment of the phasic contractions and 2) a delayed appearance of the phasic contractions without attenuation of magnitude. However, ryanodine with caffeine minimally affected phasic component by ACh- and K-induced contractions. Ryanodine pretreatment in combination with NE, ACh or K had no effect on the contractions induced by each agonist.(ABSTRACT TRUNCATED AT 250 WORDS)

The uptake of manganese induced by agonists in the isolated vas deferens of the guinea pig.

The uptake of manganese (Mn) induced by 100 mM potassium (K), 10 microM norepinephrine (NE) or 10 microM acetylcholine (ACh) was measured by atomic absorption spectroscopy in isolated vas deferens of the guinea pig. The agonists at these concentrations caused the maximal contraction of the vas deferens. The contents of Mn were increased with the repetitive treatments of Mn with K and were not significantly decreased after 1 h washing. The uptake of Mn was also stimulated by NE and ACh. The stimulation of uptake of Mn by K was the most potent while that by ACh was the smallest. The uptake of Mn was enhanced by elimination of Ca from the medium, while inhibited by the higher concentration of external Ca and by 2.1 microM diltiazem. The time course of K-induced Mn uptake was biphasic: an initial faster phase and a following slower phase of accumulation. The extents of increments of the Mn contents were dependent on the order of the applications of K and Mn: the increments became smaller in the following order, 1) when Mn was applied prior to K, 2) Mn was applied simultaneously with K, 3) Mn was applied after K. These results suggested that superficially bound Mn penetrates into the smooth muscle cells of vas deferens during the stimulation by agonists through the voltage-dependent calcium-channel (VDC) and that intracellular Mn was hardly extruded. It was also suggested that the degree of activation of VDC, through which Mn can enter the cells, was in the following order, K greater than NE greater than ACh. These results were consistent with our previous report about the dual effects of Mn: the inhibition and potentiation of contractions. It was also suggested that Mn may be a useful tool as a Ca analogue because Mn can penetrate into cells through VDC and, once taken up into the cells, Mn is not readily extruded and remains in the cells even after extracellular Mn is washed away.