Dendritic cells, interleukin 12, and CD4+ lymphocytes in the initiation of class I-restricted reactivity to a tumor/self peptide

Cell-mediated immunity involving CD8+ lymphocytes is effective in mediating rejection of murine mastocytoma cells bearing P815AB, a tumor-associated and self antigen showing similarity to tumor-specific shared antigens in humans. Although this antigen may act as an efficient target for class I-restricted responses in immunized mice, neither P815AB expressed on tumor cells nor a related synthetic nonapeptide will activate unprimed CD8+ cells for in vivo reactivity, measured by skin test assay. We review evidence showing that the failure of P815AB to initiate CD8+ cell reactivity may be due to defective recruitment of accessory and Th1-like cells to the afferent phase of the response initiated by transfer of mice with dendritic cells pulsed in vitro with the P815AB peptide. Although the copresence of a T helper peptide in dendritic cell priming in vitro with P815AB may compensate for the poor generation of accessory and Th1 cells in the adoptively transferred mice, recombinant IL-12 can replace the helper peptide in both effects. Effective priming to P815AB in vivo is achieved by either exposing dendritic cells to IL-12 prior to P815AB priming or administering the recombinant cytokine in vivo. Different approaches suggest that IL-12 may act both on accessory cells to improve presentation of previously undescribed class II-restricted epitopes of P815AB and on CD4+ cells to improve recognition of such epitopes. In particular, at the CD4+ cell level, IL-12 apparently acts as an adjuvant and an inhibitor of anergy induction. These data offer useful information for developing vaccination strategies using dendritic cells and class I-restricted tumor peptides in humans.

[Determination of brain death in Intensive Pediatric Therapy]

The subject of this paper is to report our experience in the determination of brain death in infants and children. We have retrospectively examined the incidence of brain death occurred in 504 consecutive children admitted to multidisciplinary pediatric ICU at "Bambino Gesù" Hospital of Rome during the years 1994 to 1997. According to current Italian Law, brain death was declared in 8 children (1.6%), whose primary diagnoses were: Meningitis (3 cases); nontraumatic intracerebral hemorrhage (2 cases); medulloblastoma (1 case); brain metastasis of neuroblastoma (1 case); SIDS (1 case). All brain death diagnoses were made using clinical criteria and confirmatory tests. A difficult problem was met in achieving the required Pa-CO2 values higher than 60 mmHg without unduly lowering O2 saturation. In order to obtain easily this objective we have recently switched the ventilator to intermittent mandatory volume ventilation at a rate of five stroke per minute using a FiO2 of 1 before starting the apnea test. In infants younger than one year the required cerebral circulatory arrest was documented in the pericallosal artery by doppler ultrasonography performed through the fonticuli cranii. The absence of cerebral blood flow was recorded for one to five days after clinical and electroencephalographic diagnosis of brain death, causing an unnecessary prolonged rianimative support. This also confirms that in young infants brain death may occur without a marked increase of intracranial pressure. Last, but not least, we believe that particular attention must be paid to psycho-emotional conditions of parents as well as of intensivists and nurses especially when brain death must be assessed in children.

The serum assay of soluble CD44 standard (sCD44-st), CD44 splice variant 5 (sCD44-v5), and CD44 splice variant 6 (sCD44-v6) in patients with cervical cancer

The pretreatment serum levels of soluble CD44 standard (sCD44st), CD44 splice variant 5 (sCD44-v5), and CD44 splice variant 6 (sCD44-v6) were retrospectively measured in 37 patients with untreated cervical cancer and in 36 patients with benign gynecological diseases as controls. Median sCD44-st levels were significantly higher in patients with cervical cancer than in controls (547 ng/ml, range 244-880 ng/ml versus 400.5 ng/ml, range 217-723 ng/ml, p = 0.004), whereas sCD44-v5 and sCD44-v6 concentrations were significantly lower in the former (34 ng/ml, range 0-140 ng/ml versus 44 ng/ml, range 11-109 ng/ml, p = 0.038; and 37 ng/ml, range 1-191 ng/ml versus 52.5 ng/ml, range 11-173 ng/ml, p = 0.007, respectively). sCD44-st, sCD44-v5, and sCD44-v6 levels were not related to FIGO stage and histologic type. Moreover, among patients with stage Ib-IIa cervical cancer, the preoperative levels of these glycoproteins correlated with neither the common prognostic variables nor the clinical outcome. Therefore, the serum assay of sCD44-st, sCD44-v5, and sCD44-v6 seems to have no clinical relevance for the management of patients with cervical cancer.

Tumor-associated trypsin inhibitor (TATI) and renal function

Tumor-associated trypsin inhibitor (TATI) is a low molecular weight protein employed as tumor marker. To evaluate the role of the kidney in the clearance of TATI we studied the relationship of serum TATI with the glomerular filtration rate (GFR), and for comparisons the relationships of beta 2-microglobulin (beta(2m)) and creatinine with GFR. Urine excretion and renal extraction of TATI were also determined. The decrease in GFR was accompanied by an increase in blood levels of TATI, beta(2m) and creatinine. Serum TATI increased 12.4 times in patients with renal failure (GFR < 20 ml/min) with respect to subjects with normal renal function (P < 0.001, non-parametric Mann-Whitney test), while beta(2m) increased 7.3 times (P < 0.001) and creatinine 4.7 times (P < 0.001). In patients with GFR 60 to 40 ml/min, only the increase in TATI was statistically significant (p < 0.005). Renal excretion of TATI was low but it increased progressively in renal failure. Renal extraction ranged from 13% to 41%, for a mean 24.87. These results suggest that TATI is handled by the kidney and that it is a snesitrive marker of reduction in renal function.

Serum assay of soluble CD44 standard (sCD44-st), CD44 splice variant v5 (sCD44-v5), and CD44 splice variant v6 (sCD44-v6) in patients with epithelial ovarian cancer

Different variants of the cell adhesion molecule CD44 have been involved in malignant transformation and cancer metastasis. In the present investigation we assessed the preoperative serum levels of soluble CD44 standard (sCD44-st), sCD44 splice variant 5 (sCD44-v5), and sCD44 splice variant 6 (sCD44-v6) in 51 patients with ovarian cancer. Median preoperative sCD44-st, sCD44v5, and sCD44-v6 levels were 417 ng/ml (range, 240- > 602 ng/ml), 78 ng/ml (range, 5-314 ng/ml), and 86 ng/ml (range, 1-243 ng/ml), respectively. No significant relationship was detected between sCD44-st concentrations and the common clinicopathological variables. Conversely, sCD44-v5 and sCD44-v6 levels were significantly lower in FIGO stage III-IV than in stage I disease (p < 0.0001 and p = 0.001, respectively). Moreover, with regard to advanced ovarian cancer, sCD44-v5 levels were lower in patients with poorly differentiated (G3) than in those with moderately (G2) or well (G1) differentiated tumors (p = 0.038), as well as in patients whose residual disease was > 2 cm than in those with smaller residuum (p = 0.025). Similarly, sCD44-v6 levels were lower in patients with large residual disease (p = 0.05). The median value of serum sCD44-v6 was lower in patients with G3 than in those with G1-G2 tumor, but the difference was not significant. In conclusion, sCD44-st, sCD44-v5, and sCD44-v6 are detectable in sera from patients with epithelial ovarian cancer. A reduction in preoperative sCD44-v5 and sCD44-v6 levels seems to be associated with advanced, poorly differentiated tumors and with large residual disease after first surgery, and it might reflect an increased biological aggressiveness of the malignancy.

Circulating levels of IL-10 are critically related to growth and rejection patterns of murine mastocytoma cells

Previously tumorigenic P815 tumor cells are rejected by histocompatible mice after transfection with a mutated retroviral gene, and the host is made resistant to subsequent challenge with tumorigenic (control) cells transfected with the nonmutated sequence. To functionally characterize the class I-restricted response to the tumor cell vaccine, we have assessed the in vitro (by CD8+ cells) and in vivo production of type 1 or type 2 cytokines in mice injected with either type of transfected P815 derivative. IL-12 and IL-10 were selectively or preferentially expressed by the regressor mice, and this correlated with the detection of functional type 1 reactivity in vivo (i.e., delayed-type hypersensitivity). Other cytokines were produced by the regressor mice only in vitro (IFN-gamma) or were not detected at all with either type of tumor recipient (IL-4). By means of monoclonal antibody-mediated neutralization or enhancement of endogenous cytokine levels, IL-10 was found to serve an important role in the growth and rejection patterns of the transfected P815 derivatives. In addition to previous evidence for an IL-12 requirement in promoting anti-P815 reactivity, these data establish IL-10 as an important cytokine in permitting optimal expression of this reactivity, which apparently develops in the absence of a strong bias toward a type 1 or type 2 cytokine response.

Reduction of urinary 8-epi-prostaglandin F2 alpha during cyclo-oxygenase inhibition in rats but not in man

1. 8-epi-prostaglandin (PG) F2 alpha, a major F2 isoprostane, is produced in vivo by free radical-dependent peroxidation of lipid-esterified arachidonic acid. Both cyclo-oxygenase isoforms (COX-1 and COX-2) may also form free 8-epi-PGF2 alpha as a minor product. It has been recently seen in human volunteers that the overall basal formation of 8-epi-PGF2 alpha in vivo is mostly COX-independent and urinary 8-epi-PGF2 alpha is therefore an accurate marker of 'basal' oxidative stress in vivo. 2. To test the validity of this marker in the rat, we evaluated in vivo the effect of COX inhibition on the formation of 8-epi-PGF2 alpha vs prostanoids. Two structurally unrelated COX inhibitors (naproxen: 30 mg kg-1 day-1; indomethacin: 4 mg kg-1 day-1) were given i.p. to rats kept in metabolic cages. In vivo formation of 8-epi-PGF2 alpha was assessed by measuring its urinary excretion. Prostanoid biosynthesis was assessed by measuring urinary excretion of major metabolites of thromboxane (TX) and prostacyclin (2,3-dinor-TXB1 and 2,3-dinor-6-keto-PGF1 alpha). All compounds were selectively measured by immunopurification/gas chromatography-mass spectrometry. 3. Naproxen reduced urinary excretion of 2,3-dinor-TXB1 and 2,3-dinor-6-keto-PGF1 alpha but, unexpectedly, also that of 8-epi-PGF2 alpha (82, 49 and 52% inhibition, respectively). Indomethacin had a similar effect (77, 69 and 55% inhibition). Esterified 8-epi-PGF2 alpha in liver and plasma remained unchanged after indomethacin. 4. These findings prompted us to re-assess the contribution of COX activity to the systemic production of 8-epi-PGF2 alpha in man. We gave naproxen (1 g day-1) to healthy subjects (four nonsmokers and four smokers). Urinary 8-epi-PGF2 alpha remained unchanged in the two groups (9.63 +/- 0.99 before vs 10.24 +/- 1.01 after and 20.14 +/- 3.00 vs 19.03 +/- 2.45 ng h-1 1.73 m-2), whereas there was a marked reduction of major urinary metabolites of thromboxane and prostacyclin (about 90% for both 11-dehydro-TXB2 and 2,3-dinor-TXB2; > 50% for 2,3-dinor-6-keto-PGF1 alpha). 5. To investigate whether rat COX-1 produces 8-epi-PGF2 alpha more efficiently than human COX-1, we measured the ex vivo formation of 8-epi-PGF2 alpha and TXB2 simultaneously in whole clotting blood. Serum levels of 8-epi-PGF2 alpha and TXB2 were similar in rats and man. 6. We conclude that a significant amount of COX-dependent 8-epi-PGF2 alpha is present in rat but not in human urine under normal conditions. This implies that urinary 8-epi-PGF2 alpha cannot be used as an index of near-basal oxidant stress in rats. On the other hand, our data further confirm the validity of this marker in man.

p75 neurotrophin receptor induction and macrophage infiltration in peripheral nerve during experimental diabetic neuropathy: possible relevance on regeneration

In this study we examined the expression of the neurotrophin receptor p75 (p75NTR) and the activation of macrophages in the sciatic nerve of rats at different time points after the induction of diabetes with streptozotocin (STZ). Northern blot and immunocytochemical analysis showed that p75NTR was not detectable in the sciatic nerve by Week 2 after STZ treatment. At this time, single nerve fiber immunostaining using ED1 monoclonal antibody revealed that active macrophages were infiltrating the endoneurium, which had a normal morphological aspect. By Weeks 5 and 15 p75NTR mRNA and protein were induced in the endoneurium of diabetic animals. Immunocytochemical analysis of teased single nerve fibers showed that p75NTR protein was distributed uniformly along isolated fibers with no pathological evidence of axonal degeneration or myelin disruption. At this time, cells of the phagocyte lineage had already disappeared from the nerve. These data show that during experimental diabetic neuropathy, the endoneurial induction of p75NTR is localized along isolated nerve fibers showing no morphological alterations, and in time, follows the recruitment of active macrophages in the nerve, suggesting that these cells, directly or through their products, can influence p75NTR induction. This process might play an important role in STZ diabetic neuropathy, as a response to decreased levels of neurotrophins such as NGF and promoting nerve regeneration in the early phases of the disease.

A tumor-associated and self antigen peptide presented by dendritic cells may induce T cell anergy in vivo, but IL-12 can prevent or revert the anergic state

Ag-specific CD8+ cell responses, including delayed-type hypersensitivity in vivo and IFN-gamma production in vitro, are initiated by host immunization with P815AB, a self peptide bearing CTL epitopes and expressed by murine mastocytoma cells. Using P815AB-pulsed dendritic cells (DC) and monitoring class I-restricted skin test reactivity in DC-primed mice, we have previously shown that the development of a Th1-like response to P815AB requires T helper effects, such as those mediated by coimmunization with class II-restricted (helper) peptides or by the use of rIL-12. The adjuvanticity of IL-12 was suggested to involve improved recognition of class II-restricted epitopes of P815AB. In the present study, we provide evidence for the occurrence of I-A(d)-restricted epitopes in the tumor peptide. We also show that in the absence of helper peptide or rIL-12, P81 5AB not only failed to initiate CD8+ cell responses in vivo and in vitro, but resulted in a transient state of functional unresponsiveness, characterized by a profound inability of CD4+ cells to produce IL-2 in vitro. Ag-specific T cell anergy was also observed after neutralization of endogenous IL-12 at the time of priming with P815AB plus helper peptide. All of these effects were reversed by rIL-12, which was added to DC cultures and administered to the DC-recipient mice. Anergy induction may thus contribute to P81 5AB unresponsiveness in vivo. IL-12 may act to prevent or revert anergy to this tumor-associated and self peptide.

A tumor-associated and self antigen peptide presented by dendritic cells may induce T cell anergy in vivo, but IL-12 can prevent or revert the anergic state

Ag-specific CD8+ cell responses, including delayed-type hypersensitivity in vivo and IFN-gamma production in vitro, are initiated by host immunization with P815AB, a self peptide bearing CTL epitopes and expressed by murine mastocytoma cells. Using P815AB-pulsed dendritic cells (DC) and monitoring class I-restricted skin test reactivity in DC-primed mice, we have previously shown that the development of a Th1-like response to P815AB requires T helper effects, such as those mediated by coimmunization with class II-restricted (helper) peptides or by the use of rIL-12. The adjuvanticity of IL-12 was suggested to involve improved recognition of class II-restricted epitopes of P815AB. In the present study, we provide evidence for the occurrence of I-A(d)-restricted epitopes in the tumor peptide. We also show that in the absence of helper peptide or rIL-12, P81 5AB not only failed to initiate CD8+ cell responses in vivo and in vitro, but resulted in a transient state of functional unresponsiveness, characterized by a profound inability of CD4+ cells to produce IL-2 in vitro. Ag-specific T cell anergy was also observed after neutralization of endogenous IL-12 at the time of priming with P815AB plus helper peptide. All of these effects were reversed by rIL-12, which was added to DC cultures and administered to the DC-recipient mice. Anergy induction may thus contribute to P81 5AB unresponsiveness in vivo. IL-12 may act to prevent or revert anergy to this tumor-associated and self peptide.

Cyclosporine and pregnancy in the rat

Female Wistar rats mated with male Wistar rats were given 15 mg/kg cyclosporine (CsA) per day during pregnancy (to 21 days after coitus). Other rats were mated and were used as controls. The pups born from treated mothers were fed by control mothers and those born from control mothers were fed by treated mothers. The newborn rats showed temporary defects in the development of some hemopoietic organs (the thymus, spleen, liver, and bone marrow). There was no difference in the structure of the organs studied between the litters fed by control mothers and those fed by treated mothers. The structure of the hemopoietic organs resembled those of the controls 30 days after birth. Our findings show that the delay in the development of the organs studied is due to the transplacental passage of CsA and suggest that it could be due to CsA interference in the maternal immune response to specific embryonic antigens.

Constitutive expression of heat shock proteins 70 and 90 in rat cerebellum

Exposure to heat shock and other stressful conditions activates in cells of all organisms a specific genetic program. This enhances the synthesis of proteins with a protective role against cellular damage, called heat shock proteins (hsps). Furthermore, in the mammalian nervous system, a considerable amount of hsps is also synthesized under normal conditions suggesting that they play an important role in the metabolism of unstressed cells. In this study we analysed the constitutive expression of proteins belonging to the hsp70 and hsp90 family in the rat cerebellum using immunocytochemistry with specific monoclonal antibodies. Our results showed that an intense immunostaining was evident, but was restricted in certain distinct cerebellar areas only, while no differences in the distribution of the two hsps were found. The strongest response was detected in the Purkinje neurons but deep cerebellar nuclei were also positive. In no case glial cells were found to be reactive for hsps despite their strong response for specific markers like glial fibrillary acid protein (astrocytes) and cyclic nucleotide phosphodiesterase (oligodendrocytes). These data indicate that both the hsp70 and hsp90 family have fundamental physiological functions in cerebellar neurons while they seem to play only a minor role in the metabolism of glial cells.

Detection of Vibrio anguillarum by a sandwich enzyme-linked immunosorbent assay performed with monoclonal antibodies

Monoclonal antibodies (Mabs) against V. anguillarum were produced and characterized by Western blotting analysis, competitive binding assays and cross-reactivity tests. Their ability to detect V. anguillarum in a liquid culture was tested in a sandwich enzyme-linked immunosorbent assay (ELISA) performed with different combinations of these Mabs used as capture or tracer antibodies. One combination was selected as the most suitable for diagnostic applications, showing the highest sensitivity and specificity.

Injection site effects on the pharmacokinetics and glucodynamics of insulin lispro and regular insulin

OBJECTIVE

The pharmacokinetics and glucodynamics of a new insulin analog, insulin lispro, and regular human insulin were compared and contrasted after subcutaneous administrations in femoral, deltoid, and abdominal injection sites.

RESEARCH DESIGN AND METHODS

Single 0.2 U/kg doses of insulin lispro and regular insulin were administered to 12 healthy subjects in a six-way randomized crossover fashion. Each dose was given after an overnight fast in one of three injection sites: abdominal, deltoid, or femoral. Study drugs were given during a manual euglycemic glucose clamp. Blood samples were collected over the 12-h clamp for measurement of insulin-reactive components, with pharmacokinetic and glucodynamic measurements derived from these serum insulin and clamp measurements.

RESULTS

Glucodynamic comparisons between insulin lispro and regular insulin showed a greater maximum infusion rate (Rmax) at an earlier time (TRmax), regardless of injection site. The total glucose infused (Gtot) showed nearly identical values between sites for insulin lispro. Regular insulin showed greater Gtot values from deltoid and femoral injections. When comparisons were made between drugs, regular insulin produced significantly greater Gtot, primarily driven by the increased Gtot from deltoid and femoral injections. Greater maximum serum insulin concentrations (Cmax) were experienced with insulin lispro at earlier times (tmax), regardless of the injection site (P < 0.001). Abdominal administrations produced the greatest Cmax values at the earliest tmax for both regular insulin and insulin lispro. Deltoid and femoral injections had lower Cmax values for both compounds. Shifts also occurred with tmax, although these shifts were much greater with regular insulin than with insulin lispro. Equivalent area under the curve (AUC) values were found when compared between compounds.

CONCLUSIONS

Slower absorption from deltoid and femoral administrations resulted in an increased duration of action for both regular insulin and insulin lispro when compared to abdominal administration. However, notable increases in the onset of action were only apparent with regular insulin. The consistency with insulin lispro response from abdominal and extremity injection sites allows more potential sites for subcutaneous injection with an assured rapid response.

Tyrosine phosphorylation of myelin protein PO

Po (M(r) 30 kDa), the major protein component of peripheral nervous system (PNS) myelin, is known to be phosphorylated by protein kinase C on serine residues at multiple sites. This study was conducted to assess whether other amino acids might be phosphorylated in the protein. Segments of rat sciatic nerve were incubated with 32P in either the presence or absence of phorbol ester. Labeled Po was isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subjected to partial acid hydrolysis. Upon separation of the hydrolysis products by either thin-layer electrophoresis or thin-layer chromatography, a radioactive spot was detected which comigrated with authentic phosphotyrosine. In other experiments, nerves were incubated with the tyrosine phosphatase inhibitors vanadate or vanadyl hydroperoxide (pervanadate). When the nerve homogenate proteins were separated on gels and probed with a monoclonal antibody to phosphotyrosine on Western blots, a positive immune reaction was obtained for a protein species which migrated with the same mobility as PO on Coomassie Blue-stained gels. In the absence of 2-mercaptoethanol, this immunoreactive band displayed increased mobility on gels which is characteristic of the migration pattern of Po. The same immunostaining results were obtained using a purified peripheral myelin fraction prepared from nerve homogenates. Furthermore, the positions of immunoreactive bands produced by anti-Po and antiphosphotyrosine antibodies coincided on the same immunoblot of myelin proteins and purified Po. These data indicate that one or more tyrosyl residues in Po can be phosphorylated in intact sciatic nerve.

Serum tumour-associated trypsin inhibitor (TATI) and renal function

Tumour-associated trypsin inhibitor (TATI) is a low molecular weight (MW) protein employed as a tumour marker. The blood levels of some low MW proteins increase in renal insufficiency. The aim of this study is to evaluate the relationship between serum TATI and glomerular filtration rate (GFR). Serum beta 2-microglobulin (beta 2M) and plasma creatinine were also determined. The decrease of GFR was accompanied by an increase in the other parameters. The maximum increase of TATI was from a mean basal value of 8.51 +/- 5.58 micrograms l-1 in subjects with normal renal function to 107.27 +/- 63.34 micrograms l-1 in patients with renal failure; beta 2M increased from 1.45 +/- 0.38 to 11.16 +/- 5.73 mg l-1 and creatinine from 1.05 +/- 0.17 to 5.07 +/- 1.93 mg dl-1. The increase in TATI occurs sooner and is greater than that of beta 2M and of creatinine. These results suggest that TATI is handled by the kidney. It is sensitive marker of reduction in renal function. When TATI is used as a tumour marker, renal function must be taken into account in the evaluation of the results.

S-100 (alpha and beta) binding peptide (TRTK-12) blocks S-100/GFAP interaction: identification of a putative S-100 target epitope within the head domain of GFAP

Alignment of previously characterized S-100 (alpha and beta)-binding peptides (J. Biol. Chem. 270, 14651-14658) has enabled the identification of a putative S-100 target epitope within the head domain of glial fibrillary acidic protein (GFAP). The capacity of a known peptide inhibitor of S-100 protein (TRTK-12), homologous to this region, to perturb the interaction of S-100 (alpha and beta) and GFAP (J. Biol. Chem 268, 12669-12674) was investigated. Fluorescence spectrophotometry and chemical cross-linking analyses determined TRTK-12 to disrupt S-100:GFAP interaction in a dose- and Ca(2+_dependent manner. TRTK-12 also inhibited S-100's ability to block GFAP assembly and to mediate disassembly of preformed glial filaments. Each of these events was strictly dependent upon the presence of calcium and inhibitory peptide, maximal inhibition occurring at a concentration of TRTK-12 equivalent to the molar amount of S-100 monomer present. Together with our recent report demonstrating TRTK-12 also blocks the interaction of S-100 protein with the actin capping protein, CapZ, these results suggest TRTK-12 functions as a pleiotropic inhibitor of S-100 function. Availability of a functional inhibitor of S-100 will assist the further characterization of S-100 protein function in vitro and in vivo. Moreover, this report provides additional evidence supportive of a role for S-100 as a multi-faceted regulator of cytoskeletal integrity.

A retroviral peptide encoded by mutated env p15E gene is recognized by specific CD8+ T lymphocytes on drug-treated murine mastocytoma P815

Highly immunogenic ("xenogenized") tumour variants appear after treatment of murine mastocytoma P815 with the triazene derivative DTIC, a phenomenon associated with the appearance of structurally abnormal p15E env proteins in the variant cells. In the present study, we have isolated and sequenced several p15E cDNA gene fragments amplified by means of polymerase chain reaction (PCR) from parental (P815) and xenogenized (P815/DTIC) tumour cells. Compared to known p15E sequences in parental cells, one p15E sequence from xenogenized cells presented three distinct nucleotide changes, one of which was apparently unique to P815/DTIC DNA and cDNA upon single-nucleotide primer extension assay. One major histocompatibility complex (MHC) class I-binding peptide, corresponding to a putative mutation in the p15E sequence, was tested in parallel with the parental peptide for recognition by P815/DTIC-specific cytotoxic T cells in vitro. The results suggested that the amino acid substitution at the relevant position of the p15E protein may produce an antigenic T cell epitope. By skin test assay of mice primed with either the synthetic peptide or P815/DTIC cells, evidence was obtained that the mutated peptide is immunogenic in vivo, and that the neoepitope is expressed by P815/DTIC cells. In accordance with previous data in the L5178Y/DTIC tumour model system, these findings reinforce the notion that xenogenization of tumour cells may result in the expression of class I-binding mutated peptides of retroviral origin.

Immunohistochemical characterization of thymic macrophages in normal and treated rats: a differential sensitivity to cyclosporine A

In the present study, a set of two monoclonal antibodies (TRPM1, TRPM2) was used to investigate the macrophage populations in the rat thymus and their different sensitivities to cyclosporine-A (CsA). With double immunohistochemical staining we demonstrated that, in the normal rat thymus, there are 3 populations of macrophages (TRPM1+, TRPM1/2+, TRPM2+), present in different proportions throughout the thymus. In the outer cortex TRPM1+ and TRPM1/2+ were present, but the TRPM1/2+ cells were more numerous. No TRPM2+ cells were observed in this area. The cortex and medulla showed all 3 types of cells with a majority of TRPM1/2+ cells. In the corticomedullary zone (CMZ) TRPM1/2+ and TRPM2+ macrophages were present in about equal proportion while only a few TRPM1+ cells were observed. After CsA treatment (for 21 days) profound changes occurred in the thymus; we observed a complete disappearance of the thymic medulla and a reduction in the total number of macrophages. The TRPM1+ macrophages had been eliminated, a few TRPM1/2+ cells were found while many of the cells were TRPM2+. The presence of the macrophages in different thymic areas suggests that they are a very heterogeneous population. The possible significance of the macrophage heterogeneity and the relationship to CsA sensitivity is discussed.

Simultaneous dobutamine stress echocardiography and dobutamine scintigraphy (99mTc-MIBI-SPET) for assessment of coronary artery disease

BACKGROUND

Simultaneous dobutamine stress echocardiography (DSE) and 99Tc-MIBI-SPET (DMS) for the evaluation of the presence and the extent of coronary artery disease (CAD) were assessed for a head to head comparison regarding the diagnostic acuracy of the two rests.

METHODS AND RESULTS

Forty-five consecutive patients (33 males and 12 females: 53 +/- 6.8 yr.) underwent exercise electrocardiography and simultaneous dobutamine stress echocardiography and MIBI-SPET imaging. Coronary angiography was performed in all patients (significant coronary stenosis > 50%). On the basis of the results of exercise electrocardiogram the pre-test probability for coronary artery disease (Diamond's algorithm) was low (45.6 +/- 12.7%). The overall specificity, sensitivity and predictive accuracy of Echo-dobutamine stress test for diagnosis of the presence or absence of CAD were: specificity 82%, sensitivity 76%, diagnostic accuracy 80%, positive predictive value 90%, negative predictive value 40%. The overall specificity, sensitivity and predictive accuracy of MIBI-SPET-dobutamine test for diagnosis of the presence or absence of CAD were: specificity 86%, sensitivity 87%, diagnostic accuracy 84%, positive predictive value 97%, negative predictive value 54%. MIBI-SPET-dobutamine test showed a significantly higher sensitivity in comparison with ECHO-dobutamine test (P < 0.05).

CONCLUSION

Both noninvasive methods for the detection of CAD showed a good diagnostic accuracy. Nevertheless the SPET model showed a higher sensitivity in comparison with DSE model, essentially in the presence of a lower extent of CAD and during submaximal test.

IL-12 is both required and sufficient for initiating T cell reactivity to a class I-restricted tumor peptide (P815AB) following transfer of P815AB-pulsed dendritic cells

Delayed-type hypersensitivity responses, mediated by CD8+ cells and detected by skin test assay, occur in sensitized mice in response to challenge with a class I-restricted synthetic peptide related to a poorly immunogenic tumor rejection Ag, P815AB, of murine mastocytoma cells. Efficient priming for this response, which requires functional CD4+ cells and production of IFN-gamma in the host, is achieved by transfer of dendritic cells (DC) pulsed in vitro with a physical mixture of P815AB and T helper peptides, such as a class II-restricted synthetic peptide of tetanus toxin. We now show that the adjuvant effect of the T helper peptide was associated with the appearance of early and late IL-12 transcripts in the spleens of DC recipient mice, correlated with a late IFN-gamma response, and was negated by serologic ablation of endogenous IL-12 at the time of cell transfer. rIL-12, administered in vivo to the DC recipient mice, could substitute for the T helper peptide in initiating skin test reactivity following transfer of DC pulsed with P815AB alone, leading to Ag-specific production of IFN-gamma by CD4+ and CD8+ T cells. In vitro and in vivo cell depletion experiments suggested the following: 1) the exogenous IL-12 required both CD4+ and CD8+ cells for activity; 2) the immune response initiated by IL-12 relied on later production of IL-12 by the host; and 3) the early adjuvanticity of the exogenous IL-12 involved improved recognition of class II-restricted epitopes of this otherwise poorly immunogenic tumor peptide.

IL-12 is both required and sufficient for initiating T cell reactivity to a class I-restricted tumor peptide (P815AB) following transfer of P815AB-pulsed dendritic cells

Delayed-type hypersensitivity responses, mediated by CD8+ cells and detected by skin test assay, occur in sensitized mice in response to challenge with a class I-restricted synthetic peptide related to a poorly immunogenic tumor rejection Ag, P815AB, of murine mastocytoma cells. Efficient priming for this response, which requires functional CD4+ cells and production of IFN-gamma in the host, is achieved by transfer of dendritic cells (DC) pulsed in vitro with a physical mixture of P815AB and T helper peptides, such as a class II-restricted synthetic peptide of tetanus toxin. We now show that the adjuvant effect of the T helper peptide was associated with the appearance of early and late IL-12 transcripts in the spleens of DC recipient mice, correlated with a late IFN-gamma response, and was negated by serologic ablation of endogenous IL-12 at the time of cell transfer. rIL-12, administered in vivo to the DC recipient mice, could substitute for the T helper peptide in initiating skin test reactivity following transfer of DC pulsed with P815AB alone, leading to Ag-specific production of IFN-gamma by CD4+ and CD8+ T cells. In vitro and in vivo cell depletion experiments suggested the following: 1) the exogenous IL-12 required both CD4+ and CD8+ cells for activity; 2) the immune response initiated by IL-12 relied on later production of IL-12 by the host; and 3) the early adjuvanticity of the exogenous IL-12 involved improved recognition of class II-restricted epitopes of this otherwise poorly immunogenic tumor peptide.