Coupling assembly of the E-cadherin/beta-catenin complex to efficient endoplasmic reticulum exit and basal-lateral membrane targeting of E-cadherin in polarized MDCK cells

The E-cadherin/catenin complex regulates Ca++-dependent cell-cell adhesion and is localized to the basal-lateral membrane of polarized epithelial cells. Little is known about mechanisms of complex assembly or intracellular trafficking, or how these processes might ultimately regulate adhesion functions of the complex at the cell surface. The cytoplasmic domain of E-cadherin contains two putative basal-lateral sorting motifs, which are homologous to sorting signals in the low density lipoprotein receptor, but an alanine scan across tyrosine residues in these motifs did not affect the fidelity of newly synthesized E-cadherin delivery to the basal-lateral membrane of MDCK cells. Nevertheless, sorting signals are located in the cytoplasmic domain since a chimeric protein (GP2CAD1), comprising the extracellular domain of GP2 (an apical membrane protein) and the transmembrane and cytoplasmic domains of E-cadherin, was efficiently and specifically delivered to the basal-lateral membrane. Systematic deletion and recombination of specific regions of the cytoplasmic domain of GP2CAD1 resulted in delivery of <10% of these newly synthesized proteins to both apical and basal-lateral membrane domains. Significantly, >90% of each mutant protein was retained in the ER. None of these mutants formed a strong interaction with beta-catenin, which normally occurs shortly after E-cadherin synthesis. In addition, a simple deletion mutation of E-cadherin that lacks beta-catenin binding is also localized intracellularly. Thus, beta-catenin binding to the whole cytoplasmic domain of E-cadherin correlates with efficient and targeted delivery of E-cadherin to the lateral plasma membrane. In this capacity, we suggest that beta-catenin acts as a chauffeur, to facilitate transport of E-cadherin out of the ER and the plasma membrane.

Cadherin function in junctional complex rearrangement and posttranslational control of cadherin expression

The role of E-cadherin, a calcium-dependent adhesion protein, in organizing and maintaining epithelial junctions was examined in detail by expressing a fusion protein (GP2-Cad1) composed of the extracellular domain of a nonadherent glycoprotein (GP2) and the transmembrane and cytoplasmic domains of E-cadherin. All studies shown were also replicated using an analogous cell line that expresses a mutant cadherin construct (T151) under the control of tet repressor. Mutant cadherin was expressed at approximately 10% of the endogenous E-cadherin level and had no apparent effect on tight junction function or on distributions of adherens junction, tight junction, or desmosomal marker proteins in established Madin-Darby canine kidney cell monolayers. However, GP2-Cad1 accelerated the disassembly of epithelial junctional complexes and delayed their reassembly in calcium switch experiments. Inducing expression of GP2-Cad1 to levels approximately threefold greater than endogenous E-cadherin expression levels in control cells resulted in a decrease in endogenous E-cadherin levels. This was due in part to increased protein turnover, indicating a cellular mechanism for sensing and controlling E-cadherin levels. Cadherin association with catenins is necessary for strong cadherin-mediated cell-cell adhesion. In cells expressing low levels of GP2-Cad1, protein levels and stoichiometry of the endogenous cadherin-catenin complex were unaffected. Thus effects of GP2-Cad1 on epithelial junctional complex assembly and stability were not due to competition with endogenous E-cadherin for catenin binding. Rather, we suggest that GP2-Cad1 interferes with the packing of endogenous cadherin-catenin complexes into higher-order structures in junctional complexes that results in junction destabilization.

Productivity and some properties of immunoglobulin specific against Streptococcus mutans serotype c in chicken egg yolk (IgY)

Hens were immunized on thighs by using whole cells of Streptococcus mutans MT8148 serotype c strain as antigen through intramuscular (im) and subcutaneous (sc) routes to investigate the difference of immunization reactions and the changes in yolk antibody activities against antigen after initial immunization. Several properties of crude IgY were examined to evaluate the stability during food processing. Results showed that the specificity of IgY of im treated hens was nearly 10 times as high as those of sc treated antibody. IgY from the hens immunized with the serotype c strain showed significant cross-reactions against serotypes e and f, while minor reactions against serotypes a, b, d, and g were observed. In thermal stability tests, IgY activity in both yolk and crude IgY decreased with the increasing temperature, from 70 to 80 degrees C, but the thermal denaturation rates between those two samples were not significantly different. The addition of high levels sucrose, maltose, glycerol, or 2% glycine displayed effective protection against thermal denaturation of IgY. Lyophilized yolk-5% gum arabic powder showed better stability against proteases.

A prognostic rule for elderly patients admitted with community-acquired pneumonia

PURPOSE

We sought to identify admission characteristics predicting mortality in elderly patients hospitalized with community-acquired pneumonia and to develop a prognostic staging system and discriminant rule.

PATIENTS AND METHODS

We retrospectively analyzed data from 2,356 patients aged > or = 65 years admitted with community-acquired pneumonia. Multivariable analyses of a derivation cohort (n = 1,000) identified characteristics associated with hospital mortality. A staging system and discriminant rule based on these characteristics were tested in a validation cohort (n = 1,356). Our discriminant rule was compared with a rule formulated from a heterogeneous adult population with community-acquired pneumonia.

RESULTS

Hospital mortality rates were 9% (derivation cohort) and 12% (validation cohort). We identified five independent predictors of mortality: age > or = 85 years [odds ratio 1.8 (95% confidence interval 1.1-3.1)], comorbid disease [odds ratio 4.1 (2.1-8.1)], impaired motor response [odds ratio 2.3 (1.4-3.7)], vital sign abnormality [odds ratio 3.4 (2.1-5.4)], and creatinine level > or = 1.5 mg/dL [odds ratio 2.5 (1.5-4.2)]. These variables stratified patients into four distinct stages with increasing mortality in the derivation cohort (Stage 1, 2%; Stage 2, 7%; Stage 3, 22%; Stage 4, 45%; P = 0.001) as well as in the validation cohort (Stage 1, 4%; Stage 2, 11%; Stage 3, 23%; Stage 4, 41%; P = 0.001). The discriminant rule developed from the derivation cohort had greater overall accuracy (77.1%) in the validation cohort than a rule formulated from a heterogeneous adult population (68.0%, P = 0.001).

CONCLUSION

Elderly patients with community-acquired pneumonia have characteristics at admission that can predict mortality. Our staging system and discriminant rule improve prognostic stratification of these patients.

Improving cephalogram analysis through feature subimage extraction

An MLP with a GA was proposed to extract feature subimages containing orthodontic landmarks. Simulated images and cephalograms were used to investigate its performance in comparison with the cross-correlation method. From the results of simulated image containing shapes with different geometrical conditions, it was shown that the fault tolerance of the MLP for rotation, scaling, brightness variety, and other anomalous deformations is good enough to overcome the clinical application problems. It was also shown that the stability, accuracy, and speed of this proposed algorithm are very promising. Moreover, the performance of the MLP can be significantly improved by collecting, more "representative" false patterns. The GA is a good approach to speed up the process of feature subimage extraction based on the fitness evaluated using the MLP.

Trends in costs of percutaneous transluminal coronary angioplasty

OBJECTIVE

To evaluate recent trends in the cost of percutaneous transluminal coronary angioplasty (PTCA), particularly the impact of newer technology and changing patient profile.

STUDY DESIGN

Retrospective study with a 6-month follow up.

PATIENTS AND METHODS

We compared the data on two groups of 100 consecutive patients admitted for elective PTCA at Yale-New Haven Hospital in 1995 and 1996. Hospital records, cineangiograms, and hospital cost accounting system were reviewed, and 6-month clinical outcomes were obtained from telephone interviews and medical chart review.

RESULTS

Demographic and clinical characteristics did not differ between the 1995 and 1996 groups of patients, nor was a difference detected in in-hospital and 6-month clinical outcomes between 1995 and 1996. Angiographic features of treated lesions were different between the two groups, with a significantly higher frequency of type C and totally occluded lesions in 1996 (p = 0.002 and p = 0.04, respectively). The total hospital costs were higher in 1996 compared with 1995 ($11,799 +/- $6189 vs $10,087 +/- $5608; p = 0.04). This difference persisted after adjustment for changes in patient population. The major factor responsible for escalating costs was a 45% increase in catheterization laboratory costs ($8575 +/- $4524 in 1996 vs $5916 +/- $3030 in 1995; P < 0.0001). In contrast, the noncatheterization costs decreased substantially during this period, largely as a result of an approximately 33% decrease in length of stay (3.75 +/- 2.66 days in 1995 vs 2.57 +/- 1.99 days in 1996; P = 0.0005). In a multiple linear regression model, the most important determinants of cost were lesion characteristics, stent use, and radiographic contrast volume.

CONCLUSIONS

Despite cost reduction efforts, the costs of PTCA are rising because of increased consumption of resources in the catheterization laboratory.

Factors related to delayed treatment and posttreatment symptom severity in Taiwanese patients with benign prostatic hyperplasia

We evaluated the sociodemographic and clinical factors of delayed treatment and posttreatment symptom severity in outpatients with benign prostatic hyperplasia (BPH). The study included 146 BPH patients treated at the National Taiwan University Hospital in early 1997. All patients were treated with alpha-adrenergic antagonists or finasteride for at least 2 weeks. A questionnaire based on Andersen's Health Behavior Model was used to assess various sociodemographic features, while the pre- and posttreatment symptoms severity was rated according to the International Prostate Symptom Score (IPSS). Multiple logistic regression was used to assess the associations of these factors with delayed treatment and posttreatment symptom severity. Subjects who had recently quit smoking or were blue-collar workers tended to delay treatment, while those who chose a medical center as the care provider for chronic diseases tended to be less likely to delay treatment. However, none of these associations were statistically significant. No enabling factors (income, insurance) or need factors (symptom scores) evaluated were associated with delayed treatment. Predisposing factors associated with higher posttreatment symptom severity were delayed treatment (over 12 months) (adjusted odds ratio [OR]: 2.67, 95% confidence interval [CI]: 1.16-6.16), quitting smoking (adjusted OR: 4.47, 95% CI: 1.34-14.94), and having never smoked (adjusted OR: 3.73, 95% CI: 1.15-12.11). Subjects with severe pretreatment symptoms were far more likely than subjects with mild pretreatment symptoms to have severe symptoms after treatment (adjusted OR: 52.69, 95% CI: 54.46-621.90). Our findings, though based on a limited number of subjects, suggest sociodemographic factors rather than objective clinical attributes (prostate specific antigen level, prostate volume, and urodynamic results) are associated with delayed treatment in Taiwanese men with BPH. Both pretreatment symptom severity and sociodemographic factors are related to posttreatment symptom severity.

Mutational analysis of the conserved cationic residues of Bacillus stearothermophilus 6-phosphoglucose isomerase

The importance in catalysis of the conserved arginine (R207) and lysine residues (K144, K294, K356, and K425) of 6-phosphoglucose isomerase from Bacillus stearothermophilus was assessed by site-directed mutagenesis and kinetic analysis. In general mutations had minor effects on the Km for fructose 6-phosphate. More dramatic effects were seen on kcat. The R207A mutant had a five orders of magnitude decrease in kcat relative to the wild-type enzyme. There was a significant recovery, by three orders of magnitude, in the kcat for the R207K mutant. The results suggest that the positive charge provided by R207 plays a critical role in the isomerization reaction. K425 was substituted with alanine, valine, phenylalanine, tryptophan and aspartate. All mutant enzymes at position 425 had kcat decreased in the range of several-hundred-fold. For the other mutants, K294A and K144A, the kcat values were 3.5% and 27% of the wild-type enzyme, respectively. No effects on catalysis were observed for the K356A mutant. The results suggest that R207, K144, K294, and K425 are located in the active site of the enzyme. The active-site location and the catalytic roles of K425 and K294 are supported further by the inhibitory effects of pyridoxal 5'-phosphate on enzymatic activities. The data also confirm the importance of K425 and K144 anticipated by the affinity labeling studies of the corresponding residues by pyridoxal 5'-phosphate in pig muscle phosphoglucose isomerase.

Diagnostic red herring in an infant with stridor

Foreign body aspiration in children may present with a variety of symptoms. We report here an unusual case of laryngeal foreign body in an infant masquerading as laryngeal web in its clinical presentation as well as radiological findings. The diagnosis was only made at endoscopy, thus emphasising the limited sensitivity of radiographic studies in identifying this condition.

Sunlamp use and the risk of cutaneous malignant melanoma: a population-based case-control study in Connecticut, USA

BACKGROUND

The relationship between cutaneous malignant melanoma and sunlamp use is examined in a Caucasian population in Connecticut, United States.

METHODS

Cases were diagnosed between 15 January 1987 and 15 May 1987 with a first primary cutaneous melanoma. Controls were obtained from the general population, frequency matched to cases by sex and age, through random digit dialling of Connecticut telephone numbers.

RESULTS

Of all study subjects, 141 (23%) cases and 95 (19%) controls reported ever having used sunlamps. The crude odds ratio (OR) for developing malignant melanoma after ever having used sunlamps was 1.30 (95% confidence interval [CI]: 0.97-1.74). This was reduced to 1.13 (95% CI: 0.82-1.54) after further adjusting for cutaneous phenotype and recreational sun exposure. Those who used more than one type of sunlamp had a threefold higher risk for melanoma compared to never users. Subgroup analyses showed that sunlamp use was associated with a greater increase in risk for melanoma among those who used sunlamps at home and those who were first exposed to sunlamps prior to 1971. The first use of sunlamps before the age of 25 showed somewhat higher risk for melanoma compared to first use later in life.

CONCLUSION

The current study provides limited evidence that use of sunlamps increases the risk of melanoma. For future studies, it is crucial that type of sunlamp, year of first use and amount of exposure are all taken into account. The association between melanoma and tanning with both UV-A and UV-B lamps and tanning under sunlamps early in life merits further investigation.

A gene on chromosome 11q23 coding for a putative glucose- 6-phosphate translocase is mutated in glycogen-storage disease types Ib and Ic

Glycogen-storage diseases type I (GSD type I) are due to a deficiency in glucose-6-phosphatase, an enzymatic system present in the endoplasmic reticulum that plays a crucial role in blood glucose homeostasis. Unlike GSD type Ia, types Ib and Ic are not due to mutations in the phosphohydrolase gene and are clinically characterized by the presence of associated neutropenia and neutrophil dysfunction. Biochemical evidence indicates the presence of a defect in glucose-6-phosphate (GSD type Ib) or inorganic phosphate (Pi) (GSD type Ic) transport in the microsomes. We have recently cloned a cDNA encoding a putative glucose-6-phosphate translocase. We have now localized the corresponding gene on chromosome 11q23, the region where GSD types Ib and Ic have been mapped. Using SSCP analysis and sequencing, we have screened this gene, for mutations in genomic DNA, from patients from 22 different families who have GSD types Ib and Ic. Of 20 mutations found, 11 result in truncated proteins that are probably nonfunctional. Most other mutations result in substitutions of conserved or semiconserved residues. The two most common mutations (Gly339Cys and 1211-1212 delCT) together constitute approximately 40% of the disease alleles. The fact that the same mutations are found in GSD types Ib and Ic could indicate either that Pi and glucose-6-phosphate are transported in microsomes by the same transporter or that the biochemical assays used to differentiate Pi and glucose-6-phosphate transport defects are not reliable.

Mechanisms of epithelial cell-cell adhesion and cell compaction revealed by high-resolution tracking of E-cadherin-green fluorescent protein

Cadherin-mediated adhesion initiates cell reorganization into tissues, but the mechanisms and dynamics of such adhesion are poorly understood. Using time-lapse imaging and photobleach recovery analyses of a fully functional E-cadherin/GFP fusion protein, we define three sequential stages in cell-cell adhesion and provide evidence for mechanisms involving E-cadherin and the actin cytoskeleton in transitions between these stages. In the first stage, membrane contacts between two cells initiate coalescence of a highly mobile, diffuse pool of cell surface E-cadherin into immobile punctate aggregates along contacting membranes. These E-cadherin aggregates are spatially coincident with membrane attachment sites for actin filaments branching off from circumferential actin cables that circumscribe each cell. In the second stage, circumferential actin cables near cell-cell contact sites separate, and the resulting two ends of the cable swing outwards to the perimeter of the contact. Concomitantly, subsets of E-cadherin puncta are also swept to the margins of the contact where they coalesce into large E-cadherin plaques. This reorganization results in the formation of a circumferential actin cable that circumscribes both cells, and is embedded into each E-cadherin plaque at the contact margin. At this stage, the two cells achieve maximum contact, a process referred to as compaction. These changes in E-cadherin and actin distributions are repeated when additional single cells adhere to large groups of cells. The third stage of adhesion occurs as additional cells are added to groups of >3 cells; circumferential actin cables linked to E-cadherin plaques on adjacent cells appear to constrict in a purse-string action, resulting in the further coalescence of individual plaques into the vertices of multicell contacts. The reorganization of E-cadherin and actin results in the condensation of cells into colonies. We propose a model to explain how, through strengthening and compaction, E-cadherin and actin cables coordinate to remodel initial cell-cell contacts to the final condensation of cells into colonies.

Expression of melan-A (MART1) in benign melanocytic nevi and primary cutaneous malignant melanoma

The Melan-A (MART1) gene encodes an antigen recognized by cytotoxic T cells. Although its expression in metastatic melanoma has been documented in the literature by several investigators, little is known about its distribution in primary melanomas and benign melanocytic nevi. In this study, we evaluated Melan-A expression immunohistochemically on sections from paraffin-embedded material of 50 benign nevi and 40 primary cutaneous melanomas using the monoclonal antibody A103. To evaluate a potential role of A103 in the differential diagnosis of melanocytic from nonmelanocytic tumors, we also analyzed a number of benign and malignant peripheral nerve sheath tumors, fibrohistiocytic tumors, and leiomyosarcomas. Immunoreactivity with A103 was present in all "nonneurotized" nevi and in all nondesmoplastic primary melanomas, both in the intraepidermal and the dermal component. Only two nevi that underwent prominent neurotization showed no staining with A103. Although all melanomas with epithelioid cells tended to be strongly positive with A103, only 4 of 13 spindle cell and desmoplastic melanomas (all positive with anti-S-100 and negative with HMB-45) were immunoreactive with A103 (two focally, two diffusely). None of the nonmelanocytic lesions expressed Melan-A. Our results confirm that Melan-A protein is broadly expressed in the majority of benign and malignant melanocytic lesions and suggest that A103 can be helpful diagnostically, not only for metastatic tumors, but also for primary skin lesions. Its use in distinguishing between melanocytic and peripheral nerve sheath tumors, however, is limited because of the low or absent expression of Melan-A in nevi that underwent neurotization and spindle cell and desmoplastic melanomas.

Expression of SSX genes in human tumors

The HOM-MEL-40 antigen which is encoded by the SSX-2 gene was originally detected as a tumor antigen recognized by autologous IgG antibodies in a melanoma patient. Expression analysis demonstrated that SSX-2 is a member of the recently described cancer/testis antigen (CTA) class as it is expressed in a variety of different human neoplasms, but not in normal tissues with the exception of testis and a weak expression in the thyroid. Further studies demonstrated that SSX-2 belongs to a gene family consisting of at least 5 homologous genes. We now report the analysis of the expression of all 5 SSX genes in 325 specimens of human neoplasms from various histological origins, using reverse transcription polymerase chain reaction (RT-PCR). SSX-1, -2, and -4 were found to be expressed in 8%, 15% and 15%, of the tumors, respectively, while the expression of the SSX-5 gene was rare (7/325), and SSX-3 expression was not detected. For defined tumor types, expression of at least one of the SSX family members was most frequently observed in head and neck cancer (75%), followed by ovarian cancer (50%), malignant melanoma (43%), lymphoma (36%), colorectal cancer (27%) and breast cancer (23%), while leukemias and the few cases of leiomyosarcomas, seminomas and thyroid cancers were found not to express any SSX gene.

Expression of SSX genes in human tumors

The HOM-MEL-40 antigen which is encoded by the SSX-2 gene was originally detected as a tumor antigen recognized by autologous IgG antibodies in a melanoma patient. Expression analysis demonstrated that SSX-2 is a member of the recently described cancer/testis antigen (CTA) class as it is expressed in a variety of different human neoplasms, but not in normal tissues with the exception of testis and a weak expression in the thyroid. Further studies demonstrated that SSX-2 belongs to a gene family consisting of at least 5 homologous genes. We now report the analysis of the expression of all 5 SSX genes in 325 specimens of human neoplasms from various histological origins, using reverse transcription polymerase chain reaction (RT-PCR). SSX-1, -2, and -4 were found to be expressed in 8%, 15% and 15%, of the tumors, respectively, while the expression of the SSX-5 gene was rare (7/325), and SSX-3 expression was not detected. For defined tumor types, expression of at least one of the SSX family members was most frequently observed in head and neck cancer (75%), followed by ovarian cancer (50%), malignant melanoma (43%), lymphoma (36%), colorectal cancer (27%) and breast cancer (23%), while leukemias and the few cases of leiomyosarcomas, seminomas and thyroid cancers were found not to express any SSX gene.

Expression of SSX genes in human tumors

The HOM-MEL-40 antigen which is encoded by the SSX-2 gene was originally detected as a tumor antigen recognized by autologous IgG antibodies in a melanoma patient. Expression analysis demonstrated that SSX-2 is a member of the recently described cancer/testis antigen (CTA) class as it is expressed in a variety of different human neoplasms, but not in normal tissues with the exception of testis and a weak expression in the thyroid. Further studies demonstrated that SSX-2 belongs to a gene family consisting of at least 5 homologous genes. We now report the analysis of the expression of all 5 SSX genes in 325 specimens of human neoplasms from various histological origins, using reverse transcription polymerase chain reaction (RT-PCR). SSX-1, -2, and -4 were found to be expressed in 8%, 15% and 15%, of the tumors, respectively, while the expression of the SSX-5 gene was rare (7/325), and SSX-3 expression was not detected. For defined tumor types, expression of at least one of the SSX family members was most frequently observed in head and neck cancer (75%), followed by ovarian cancer (50%), malignant melanoma (43%), lymphoma (36%), colorectal cancer (27%) and breast cancer (23%), while leukemias and the few cases of leiomyosarcomas, seminomas and thyroid cancers were found not to express any SSX gene.

Expression of SSX genes in human tumors

The HOM-MEL-40 antigen which is encoded by the SSX-2 gene was originally detected as a tumor antigen recognized by autologous IgG antibodies in a melanoma patient. Expression analysis demonstrated that SSX-2 is a member of the recently described cancer/testis antigen (CTA) class as it is expressed in a variety of different human neoplasms, but not in normal tissues with the exception of testis and a weak expression in the thyroid. Further studies demonstrated that SSX-2 belongs to a gene family consisting of at least 5 homologous genes. We now report the analysis of the expression of all 5 SSX genes in 325 specimens of human neoplasms from various histological origins, using reverse transcription polymerase chain reaction (RT-PCR). SSX-1, -2, and -4 were found to be expressed in 8%, 15% and 15%, of the tumors, respectively, while the expression of the SSX-5 gene was rare (7/325), and SSX-3 expression was not detected. For defined tumor types, expression of at least one of the SSX family members was most frequently observed in head and neck cancer (75%), followed by ovarian cancer (50%), malignant melanoma (43%), lymphoma (36%), colorectal cancer (27%) and breast cancer (23%), while leukemias and the few cases of leiomyosarcomas, seminomas and thyroid cancers were found not to express any SSX gene.

Angiotensinogen gene polymorphism is associated with insulin resistance in nondiabetic men with or without coronary heart disease

BACKGROUND

Variants of the angiotensinogen gene may increase the risk of having arterial hypertension and coronary heart disease (CHD), but their effect on insulin resistance remains unknown.

METHODS

We determined M235 and T174 allele status and fasting plasma glucose, insulin, and lipids values in nondiabetic men with CHD documented on angiography (n = 102) and in a control group (n = 145). Plasma glucose and insulin responses to 75 gm oral glucose tolerant test and insulin resistance as measured by an insulin suppression test were also carried out in 46 (45%) patients with CHD and in 73 (50%) members of a control group.

RESULTS

We found no association between M235T status and blood pressure, fasting plasma glucose, insulin, most of the lipids values, and insulin resistance in patients with CHD and normal subjects. Nevertheless, compared with individuals with homozygotes T174, subjects with heterozygotes T174M were associated with greater glucose and insulin response to the oral glucose tolerance test and insulin resistance indicated by higher steady state plasma glucose concentrations in patients with CHD (14.7+/-0.9 vs 11.3+/-0.7 mmol/L, p < 0.04). Similar findings were found in the control group, with higher steady-state plasma glucose values in individuals with heterozygotes T174M than in those with homozygotes T174 (10.1+/-1.4 vs 7.7+/-0.4 mmol/L, p < 0.05).

CONCLUSION

We suggest that the angiotensinogen T174M allele might be associated with insulin resistance in nondiabetic men with and without CHD.

Characterization of human colon cancer antigens recognized by autologous antibodies

The screening of cDNA expression libraries derived from human tumors with autologous antibody (SEREX) has proven to be a powerful method for defining the structure of tumor antigens recognized by the humoral immune system. In the present study, 48 distinct antigens (NY-CO-1-NY-CO-48) reactive with autologous IgG were identified by SEREX analysis in 4 patients with colon cancer. Sequencing analysis showed that 17 of the cDNA clones were previously uncharacterized molecules and 31 represented known gene products. The individual cDNA clones were analyzed in the following manner: a search for mutations or other structural changes; an analysis of mRNA expression in a panel of normal tissues; and a frequency analysis of the antibody response to the expressed product in the sera of colon cancer patients and normal individuals. The initial analysis showed NY-CO-13 to be a mutated version of the p53 tumor suppressor gene. Three of the 48 antigens showed a differential pattern of mRNA expression, with NY-CO-27 (galectin-4) expressed primarily in gastrointestinal tract, and NY-CO-37 and -38 showing a pattern of tissue-specific isoforms. With regard to immunogenicity, 20 of the 48 antigens were detected by allogeneic sera; 14 of these were reactive with sera from both normal donors and cancer patients, and 6 other clones (NY-CO-8, -9, -13, -16, -20 and -38) reacted exclusively with sera from colon cancer patients (ranging from 14% to 27%). Our results on colon cancer illustrate both the complexity and the potential of the SEREX approach for analysis of the humoral immune response against human cancer.

Identification of multiple cancer/testis antigens by allogeneic antibody screening of a melanoma cell line library

Cancer/testis (CT) antigens-immunogenic protein antigens that are expressed in testis and a proportion of diverse human cancer types-are promising targets for cancer vaccines. To identify new CT antigens, we constructed an expression cDNA library from a melanoma cell line that expresses a wide range of CT antigens and screened the library with an allogeneic melanoma patient serum known to contain antibodies against two CT antigens, MAGE-1 and NY-ESO-1. cDNA clones isolated from this library identified four CT antigen genes: MAGE-4a, NY-ESO-1, LAGE-1, and CT7. Of these four, only MAGE-4a and NY-ESO-1 proteins had been shown to be immunogenic. LAGE-1 is a member of the NY-ESO-1 gene family, and CT7 is a newly defined gene with partial sequence homology to the MAGE family at its carboxyl terminus. The predicted CT7 protein, however, contains a distinct repetitive sequence at the 5' end and is much larger than MAGE proteins. Our findings document the immunogenicity of LAGE-1 and CT7 and emphasize the power of serological analysis of cDNA expression libraries in identifying new human tumor antigens.

Genomic cloning and localization of CTAG, a gene encoding an autoimmunogenic cancer-testis antigen NY-ESO-1, to human chromosome Xq28

CTAG was initially cloned from an esophageal squamous cell carcinoma cDNA expression library by immunoscreening with autologous patient's serum. CTAG mRNA is expressed in a proportion of human cancers in a lineage-nonspecific fashion, whereas its expression in normal tissues is restricted to testis and ovary only. This expression pattern suggests that the CTAG product (NY-ESO-1) is an aberrantly activated tumor antigen and can potentially be an antigenic target for tumor vaccination. In the present study, we isolated human genomic clones of CTAG and established its genomic organization. By somatic cell hybrid studies and fluorescence in-situ hybridization, we localized this gene to chromosome Xq28, a region that also contains members of MAGE, a gene family that encodes several immunogenic tumor antigens with the characteristic cancer/testis expression pattern.

Characterization of human colon cancer antigens recognized by autologous antibodies

The screening of cDNA expression libraries derived from human tumors with autologous antibody (SEREX) has proven to be a powerful method for defining the structure of tumor antigens recognized by the humoral immune system. In the present study, 48 distinct antigens (NY-CO-1-NY-CO-48) reactive with autologous IgG were identified by SEREX analysis in 4 patients with colon cancer. Sequencing analysis showed that 17 of the cDNA clones were previously uncharacterized molecules and 31 represented known gene products. The individual cDNA clones were analyzed in the following manner: a search for mutations or other structural changes; an analysis of mRNA expression in a panel of normal tissues; and a frequency analysis of the antibody response to the expressed product in the sera of colon cancer patients and normal individuals. The initial analysis showed NY-CO-13 to be a mutated version of the p53 tumor suppressor gene. Three of the 48 antigens showed a differential pattern of mRNA expression, with NY-CO-27 (galectin-4) expressed primarily in gastrointestinal tract, and NY-CO-37 and -38 showing a pattern of tissue-specific isoforms. With regard to immunogenicity, 20 of the 48 antigens were detected by allogeneic sera; 14 of these were reactive with sera from both normal donors and cancer patients, and 6 other clones (NY-CO-8, -9, -13, -16, -20 and -38) reacted exclusively with sera from colon cancer patients (ranging from 14% to 27%). Our results on colon cancer illustrate both the complexity and the potential of the SEREX approach for analysis of the humoral immune response against human cancer.

The impact of a clinical pathway for transurethral resection of the prostate on costs and clinical outcomes

The purpose of this study was to evaluate the effects of implementing a clinical pathway for transurethral resection of the prostate on hospital costs and procedures, outcomes, and complications. Consecutive patients who underwent transurethral resection of the prostate for benign prostate hyperplasia in our hospital before (February-August 1996) and after (October 1996-March 1997) implementation of the clinical pathway were included. Statistical analyses included Student's t-test to test the impact of the clinical pathway on resource consumption and medical care processes, and multiple linear regression to control for patient characteristics such as age, severity of disease, and comorbidity. The major findings of this study were that implementation of the clinical pathway 1) decreased resource consumption and controlled medical care expenditure; 2) influenced physicians' patterns of practice and decreased the number of procedures performed; and 3) did not affect clinical outcomes or complication rates. In conclusion, our results support the hypothesis that the clinical pathway is an effective medical management tool to contain costs, which does not adversely affect quality of care. We suggest health policy makers promote clinical pathways in more hospitals to encourage appropriate resource consumption.

Prediction of right ventricular infarction from standard surface ECG in patients with inferior myocardial infarction

BACKGROUND

Patients with inferior myocardial infarction (MI) have a 45% chance of having concurrent right ventricular infarction (RVI); of these, 5-10% suffer hemodynamic collapse. Immediate correct diagnosis and appropriate management of such patients is vital. ST-segment elevation in the right precordial V4 lead (V4R) has a high diagnostic value in identifying RVI, but this determination requires additional time and cost. An attempt was made to use a collection of patients' standard surface electrocardiograms (ECG) to find any available data to detect RVI and to lead to a new way to diagnose RVI.

METHODS

Fifty patients (males/females, 44/6; mean age, 64.3 +/- 6.9 years) with acute inferior myocardial infarction were enrolled in a first group to develop new diagnostic criteria for RVI. As a first step, the ST-segment change in every standard surface ECG lead was analyzed and compared with corresponding changes in V4R. RVI was diagnosed by typical clinical symptoms (chest pain for more than 30 minutes, ST elevation > 0.1 mV and enzyme changes) accompanying ST elevation of more than 0.1 mV in V4R (by Lopez-Sendon criteria) and echocardiographic findings. RVI was diagnosed in 24 (48%) patients using ECG. The new criteria were then tested in a secondary group of 48 patients (males/females, 43/5; mean age, 65.5 +/- 7.9 years) with inferior MI.

RESULTS

Analysis of these patients found that ST depression in lead I and aVL was a specific characteristic of RVI (I + aVL > 0.2 mV). This criterion was applied to another group of patients with acute inferior MI to check the predictive value (sensitivity, 94.7%; specificity, 89.7%; positive predictive value, 85.7%; negative predictive value, 96.3%).

CONCLUSIONS

In patients with evolving inferior MI, standard surface ECG analyzed for this criterion could aid clinical recognition of concomitant RVI.

A103: An anti-melan-a monoclonal antibody for the detection of malignant melanoma in paraffin-embedded tissues

Melan-A is a previously defined, melanocyte differentiation antigen, and an anti-Melan-A murine monoclonal antibody, A103, was recently developed by our group. In this study, we evaluated A103 immunoreactivity on formalin-fixed, paraffin-embedded tissues, exploring the potential of A103 in the diagnosis of metastatic melanoma. Seventy-five metastatic melanomas, 10 primary melanomas, and 10 benign melanocytic nevi were tested. The reactivity of A103 was compared with HMB-4, an anti-gp100 antibody. Results showed that all nevi were A103 positive, and most primary melanomas were A103 and HMB45 positive. Of 75 metastatic melanomas, 61 (81%) were A103 positive, and 56 (75%) were HMB45 positive. Of 19 HMB45-negative lesions, 8 were A103 positive; of 14 A103-negative lesions, 3 were HMB45 positive. Eleven metastatic lesions, as well as 2 of 10 primary melanomas, were dual negative. These negative cases consisted mainly of the spindle cell and desmoplastic variants. Of the positive cases, A103 showed homogeneous staining in a significantly higher proportion of cases than HMB45 (72% versus 52%). In addition, focal staining with less than 5% reactive tumor cells was seen more frequently in HMB45 (12 of 56) than in A103 (5 of 61). These results indicated that A103 can be used as a first-line antibody in the diagnosis of metastatic melanoma. Our results also showed that A103 reacted with angiomyolipoma, which is known to be HMB45 positive. Of normal tissues, unexpected A103 reactivity was observed in the adrenal cortex, granulosa and theca cells of the ovary, and Leydig cells of the testis. This A103 immunoreactivity in benign and neoplastic tissues of nonmelanocytic origin, the basis of which is unclear, could also be of potential diagnostic value.

A survey of the humoral immune response of cancer patients to a panel of human tumor antigens

Evidence is growing for both humoral and cellular immune recognition of human tumor antigens. Antibodies with specificity for antigens initially recognized by cytotoxic T lymphocytes (CTLs), e.g., MAGE and tyrosinase, have been detected in melanoma patient sera, and CTLs with specificity for NY-ESO-1, a cancer-testis (CT) antigen initially identified by autologous antibody, have recently been identified. To establish a screening system for the humoral response to autoimmunogenic tumor antigens, an enzyme-linked immunosorbent assay (ELISA) was developed using recombinant NY-ESO-1, MAGE-1, MAGE-3, SSX2, Melan-A, and tyrosinase proteins. A survey of sera from 234 cancer patients showed antibodies to NY-ESO-1 in 19 patients, to MAGE-1 in 3, to MAGE-3 in 2, and to SSX2 in 1 patient. No reactivity to these antigens was found in sera from 70 normal individuals. The frequency of NY-ESO-1 antibody was 9.4% in melanoma patients and 12.5% in ovarian cancer patients. Comparison of tumor NY-ESO-1 phenotype and NY-ESO-1 antibody response in 62 stage IV melanoma patients showed that all patients with NY-ESO-1(+) antibody had NY-ESO-1(+) tumors, and no patients with NY-ESO-1(-) tumors had NY-ESO-1 antibody. As the proportion of melanomas expressing NY-ESO-1 is 20-40% and only patients with NY-ESO-1(+) tumors have antibody, this would suggest that a high percentage of patients with NY-ESO-1(+) tumors develop an antibody response to NY-ESO-1.

Improved fluorescence and dual color detection with enhanced blue and green variants of the green fluorescent protein

The green fluorescent protein (GFP) from the jellyfish Aequorea victoria is a versatile reporter protein for monitoring gene expression and protein localization in a variety of systems. Applications using GFP reporters have expanded greatly due to the availability of mutants with altered spectral properties, including several blue emission variants, all of which contain the single point mutation Tyr-66 to His in the chromophore region of the protein. However, previously described "BFP" reporters have limited utility, primarily due to relatively dim fluorescence and low expression levels attained in higher eukaryotes with such variants. To improve upon these qualities, we have combined a blue emission mutant of GFP containing four point mutations (Phe-64 to Leu, Ser-65 to Thr, Tyr-66 to His, and Tyr-145 to Phe) with a synthetic gene sequence containing codons preferentially found in highly expressed human proteins. These mutations were chosen to optimize expression of properly folded fluorescent protein in mammalian cells cultured at 37 degreesC and to maximize signal intensity. The combination of improved fluorescence and higher expression levels yield an enhanced blue fluorescent protein that provides greater sensitivity and is suitable for dual color detection with green-emitting fluorophores.

Dopamine and dobutamine have different effects on heart rate variability in patients with congestive heart failure

BACKGROUND

Autonomic dysfunction plays an important role in the pathogenesis, treatment and prognosis of congestive heart failure (CHF). Sympathomimetic amines have been widely used in the treatment of CHF, but reports on their autonomic effects in CHF are rare. This study was designed to evaluate the effects of dopamine and dobutamine on cardiac autonomic function as assessed by heart rate variability (HRV).

METHODS

Twenty patients with symptomatic CHF (systolic dysfunction) were enrolled. After recording one-hour baseline electrocardiographs (ECGs), patients were randomly selected for either dopamine (4 micrograms/kg/minute, Group A) or dobutamine (4 micrograms/kg/minute, Group B) treatment for three days. On the third day, a 24-hour ambulatory ECG was recorded and a tilt-table test was performed. Only furosemide and nitrates were allowed for adjunctive therapy. HRV was measured before and after treatment in both time and frequency domains. Frequency-domain HRV was also measured during head-up tilt.

RESULTS

After treatment, all patients improved [New York Heart Association fraction (NYHA Fc) 3.7 to 2.0]. Group A patients had higher post-treatment 24-hour HRV than those in Group B. SDNN (standard deviation of the average normal RR intervals in the entire ECG recording), SDANN (standard deviation of the average normal RR intervals for all five minute segments of an entire ECG recording) and SDNN indices in Group A were significantly higher than in Group B (90 +/- 33 ms vs 41 +/- 12 ms, 78 +/- 32 ms vs 36 +/- 11 ms, and 37 +/- 19 ms vs 16 +/- 7 ms, respectively, all p < 0.05). rMSSD (the square root of the mean of the squared differences between adjacent normal RR intervals over the entire ECG recording) and pNN50 (percentage of differences between adjacent normal RR intervals that are greater than 50 ms computed over the entire ECG recording) were also higher in Group A patients, with borderline significance. All measurements of total frequency and low-frequency and high-frequency components tended to be higher in Group A than Group B, but this was only significant for total frequency amplitude (22.9 +/- 13.4 ms vs 10.9 +/- 6.1 ms, p < 0.05). Dopamine but not dobutamine treatment seems to restore the depressed circadian change in frequency-domain HRV classically seen in patients with CHF. The HRV change during head-up tilting did not differ between the two groups. Three patients in Group B showed non-sustained ventricular tachycardia on ambulatory ECG during the treatment period.

CONCLUSIONS

Dopamine and dobutamine have comparable therapeutic effects in patients with CHF, but low-dose dopamine more favorably affects cardiac autonomic function.

Two new mutations in the 3' coding region of the glycogen debranching enzyme in a glycogen storage disease type IIIa Ashkenazi Jewish patient

Glycogen storage disease type III (GSD III) is an autosomal recessive disease caused by the deficiency of glycogen debranching enzyme (AGL). We report the finding of two new mutations in a GSD IIIa Ashkenazi Jewish patient. Both mutations are insertion of an adenine into a stretch of 8 adenines towards the 3' end of the coding region, one at position 3904 (3904insA) in exon 30, the second at position 4214 (4214insA) in exon 32. The mutations cause frameshifts and premature terminations of the glycogen debranching enzyme, the first causing a frameshift at amino acid 1304, the second causing a frameshift at amino acid 1408 of the total of 1532. These mutations demonstrate the importance of the 125 amino acids at the carboxy-terminus of the debrancher enzyme for its activity and support the suggestion that the putative glycogen binding domain is located in the carboxy-terminus of the AGL. The mutations cause distinctive single-strand conformation polymorphism (SSCP) patterns enabling easy detection.

Human lung cancer antigens recognized by autologous antibodies: definition of a novel cDNA derived from the tumor suppressor gene locus on chromosome 3p21.3

Serological analysis of a recombinant lung cancer cDNA expression library with the autologous patient serum led to the isolation of 20 clones representing 12 different genes: 4 of these were known genes, and the other 8 were previously unknown genes. Of the four known genes, aldolase A (NY-LU-1), previously shown to be overexpressed in lung cancer, was most frequently isolated. The other three genes were annexin XI, human HIV Rev-interacting protein Rip-1, and the human homologue of the ATP-binding arsA component of the bacterial arsenite transporter, all of which are known to be widely expressed in human tissues. Among the eight unknown genes, of most interest was NY-LU-12. Cloning of full-length NY-LU-12 showed that this cDNA was derived from the same gene as g16, a partially sequenced gene that mapped to the lung cancer tumor suppressor gene locus on chromosome 3p21. The reported g16 sequence, however, was significantly shorter (2433 versus 3591 bp). As a result of alternate splicing and subsequent frameshift, the reported g16 protein is 603 amino acids shorter than the NY-LU-12 product (1123 residues) at its COOH terminus and would therefore lack the epitopes recognized by the autologous serum. Analysis of the putative NY-LU-12 protein sequence predicted that it is a nuclear zinc finger protein with two RNA-binding domains, and Southern analysis showed that this gene is partially deleted in the lung cancer line NCI-H740 but not in nine other lung cancer lines. Screening of normal and cancer patient sera showed anti-NY-LU-12 seroreactivity in 2 of 21 allogeneic lung cancer patients but not in 24 patients with other tumors or in 16 sera from healthy donors. Comparison of NY-LU-12 cDNA from Lu15 tumor and normal lung tissue by DNA sequencing and/or single-strand conformation polymorphism analysis showed no evidence of mutation. Considering the high frequency of 3p21 alterations in lung cancer and the fact that the tumor suppressor gene or genes in this locus have not been identified, additional studies on the NY-LU-12 gene and its product are warranted.

Recombinant human acid alpha-glucosidase corrects acid alpha-glucosidase-deficient human fibroblasts, quail fibroblasts, and quail myoblasts

Acid alpha-glucosidase (GAA) deficiency causes Pompe disease, a lethal lysosomal glycogen storage disease for which no effective treatment currently exists. We investigated the endocytic process in deficient cells of human recombinant GAA produced in Chinese hamster ovary cells, and the potential of GAA-deficient Japanese acid maltase-deficient quail as a model for evaluating the enzyme replacement therapy for Pompe disease. After 24-h incubation with a single dose of recombinant enzyme, intracellular GAA and glycogen levels in deficient human fibroblasts were normalized, and this correction lasted for 7 d. The 110-kD precursor recombinant enzyme was processed to the 76-kD mature form within 24 h after uptake. Intracellular GAA levels in deficient quail fibroblasts and myoblasts were similarly corrected to their average normal levels within 24 h. Differences existed in the efficiency of endocytosis among subfractions of the enzyme, and among different cell types. Fractions with a larger proportion of precursor GAA were endocytosed more efficiently. Quail fibroblasts required a higher dose, 4200 nmol.h-1.mL-1 to normalize intracellular GAA levels than human fibroblasts, 1290 nmol.h-1.mL-1, whereas primary quail myoblasts required 2800 nmol.h-1.mL-1. In all three cell lines, the endocytosed enzyme localized to the lysosomes on immunofluorescence staining, and the endocytosis was inhibited by mannose 6-phosphate (Man-6-P) added to the culture medium. Despite structural differences in Man-6-P receptors between birds and mammals, these studies illustrate that Man-6-P receptor mediated endocytosis is present in quail muscle cells, and demonstrate the potential of acid maltase-deficient quail to test receptor mediated enzyme replacement therapy for Pompe disease.

Clinical and metabolic correction of pompe disease by enzyme therapy in acid maltase-deficient quail

Pompe disease is a fatal genetic muscle disorder caused by a deficiency of acid alpha-glucosidase (GAA), a glycogen degrading lysosomal enzyme. GAA-deficient (AMD) Japanese quails exhibit progressive myopathy and cannot lift their wings, fly, or right themselves from the supine position (flip test). Six 4-wk-old acid maltase-deficient quails, with the clinical symptoms listed, were intravenously injected with 14 or 4.2 mg/kg of precursor form of recombinant human GAA or buffer alone every 2-3 d for 18 d (seven injections). On day 18, both high dose-treated birds (14 mg/kg) scored positive flip tests and flapped their wings, and one bird flew up more than 100 cm. GAA activity increased in most of the tissues examined. In heart and liver, glycogen levels dropped to normal and histopathology was normal. In pectoralis muscle, morphology was essentially normal, except for increased glycogen granules. In sharp contrast, sham-treated quail muscle had markedly increased glycogen granules, multi-vesicular autophagosomes, and inter- and intrafascicular fatty infiltrations. Low dose-treated birds (4.2 mg/kg) improved less biochemically and histopathologically than high dose birds, indicating a dose-dependent response. Additional experiment with intermediate doses and extended treatment (four birds, 5.7-9 mg/kg for 45 d) halted the progression of the disease. Our data is the first to show that an exogenous protein can target to muscle and produce muscle improvement. These data also suggest enzyme replacement with recombinant human GAA is a promising therapy for human Pompe disease.

Development of Th1 and Th2 populations and the nature of immune responses to hepatitis B virus DNA vaccines can be modulated by codelivery of various cytokine genes

In this study, we provide direct evidence that the magnitude and nature of the immune response to a DNA vaccine can be differentially regulated by codelivery of various mouse cytokine genes. Mice immunized with a hepatitis B virus (HBV) DNA vaccine and the IL-12 or IFN-gamma gene exhibited a significant enhancement of Th1 cells and increased production of anti-HBV surface IgG2a Ab, as well as a marked inhibition of Th2 cells and decreased production of IgG1 Ab. In contrast, coinjection of the IL-4 gene significantly enhanced the development of specific Th2 cells and increased production of IgG1 Ab, whereas Th1 differentiation and IgG2a production were suppressed. Coinjection of the IL-2 or the granulocyte-macrophage-CSF gene enhanced the development of Th1 cells, while the development of Th2 cells was not affected, and the production of IgG1 and IgG2a Ab were both increased. The CTL activity induced by HBV DNA vaccination was most significantly enhanced by codelivery of the IL-12 or IFN-gamma gene, followed by the IL-2 or granulocyte-macrophage-CSF gene, whereas codelivery of the IL-4 gene suppressed the activity. When challenged with HBV surface Ag (HBsAg)-expressing syngeneic tumors, significant reduction of tumor growth was observed in mice that were coadministered the IL-12 gene but not the IL-4 gene. Taken together, these results demonstrate that application of a cytokine gene in a DNA vaccine formulation can influence the differentiation of Th cells as well as the nature of an immune response and may thus provide a strategy to improve its prophylactic and therapeutic efficacy.

Simultaneous humoral and cellular immune response against cancer-testis antigen NY-ESO-1: definition of human histocompatibility leukocyte antigen (HLA)-A2-binding peptide epitopes

A growing number of human tumor antigens have been described that can be recognized by cytotoxic T lymphocytes (CTLs) in a major histocompatibility complex (MHC) class I-restricted fashion. Serological screening of cDNA expression libraries, SEREX, has recently been shown to provide another route for defining immunogenic human tumor antigens. The detection of antibody responses against known CTL-defined tumor antigens, e.g., MAGE-1 and tyrosinase, raised the question whether antibody and CTL responses against a defined tumor antigen can occur simultaneously in a single patient. In this paper, we report on a melanoma patient with a high-titer antibody response against the "cancer-testis" antigen NY-ESO-1. Concurrently, a strong MHC class I-restricted CTL reactivity against the autologous NY-ESO-1-positive tumor cell line was found. A stable CTL line (NW38-IVS-1) was established from this patient that reacted with autologous melanoma cells and with allogeneic human histocompatibility leukocyte antigen (HLA)-A2(-), NY-ESO-1-positive, but not NY-ESO-1-negative, melanoma cells. Screening of NY-ESO-1 transfectants with NW38-IVS-1 revealed NY-ESO-1 as the relevant CTL target presented by HLA-A2. Computer calculation identified 26 peptides with HLA-A2-binding motifs encoded by NY-ESO-1. Of these, three peptides were efficiently recognized by NW38-IVS-1. Thus, we show that antigen-specific humoral and cellular immune responses against human tumor antigens may occur simultaneously. In addition, our analysis provides a general strategy for identifying the CTL-recognizing peptides of tumor antigens initially defined by autologous antibody.

Direct and regulated interaction of integrin alphaEbeta7 with E-cadherin

The cadherins are a family of homophilic adhesion molecules that play a vital role in the formation of cellular junctions and in tissue morphogenesis. Members of the integrin family are also involved in cell to cell adhesion, but bind heterophilically to immunoglobulin superfamily molecules such as intracellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, or mucosal addressin cell adhesion molecule (MadCAM)-1. Recently, an interaction between epithelial (E-) cadherin and the mucosal lymphocyte integrin, alphaEbeta7, has been proposed. Here, we demonstrate that a human E-cadherin-Fc fusion protein binds directly to soluble recombinant alphaEbeta7, and to alphaEbeta7 solubilized from intraepithelial T lymphocytes. Furthermore, intraepithelial lymphocytes or transfected JY' cells expressing the alphaEbeta7 integrin adhere strongly to purified E-cadherin-Fc coated on plastic, and the adhesion can be inhibited by antibodies to alphaEbeta7 or E-cadherin. The binding of alphaEbeta7 integrin to cadherins is selective since cell adhesion to P-cadherin-Fc through alphaEbeta7 requires >100-fold more fusion protein than to E-cadherin-Fc. Although the structure of the alphaE-chain is unique among integrins, the avidity of alphaEbeta7 for E-cadherin can be regulated by divalent cations or phorbol myristate acetate. Cross-linking of the T cell receptor complex on intraepithelial lymphocytes increases the avidity of alphaEbeta7 for E-cadherin, and may provide a mechanism for the adherence and activation of lymphocytes within the epithelium in the presence of specific foreign antigen. Thus, despite its dissimilarity to known integrin ligands, the specific molecular interaction demonstrated here indicates that E-cadherin is a direct counter receptor for the alphaEbeta7 integrin.

Immunoreactivity for A103, an antibody to melan-A (Mart-1), in adrenocortical and other steroid tumors

The Melan-A (MART-1) gene encodes an antigen recognized by cytotoxic T cells. It has been said to be restricted in its expression to melanocytes. However, here we report the presence of immunoreactivity for A103, an antibody to Melan-A, in five adrenocortical adenomas, 16 primary and 13 metastatic adrenocortical carcinomas, four Leydig cell tumors of the testis, and three Sertoli-Leydig cell tumors of the ovary. To evaluate the potential diagnostic role of this antibody, we studied immunoreactivity for A103 in 111 carcinomas, 40 germ cell tumors, and 33 miscellaneous nonmelanocytic epithelioid tumors. All of them were negative for A103. Our findings suggest that once melanoma is excluded, A103 can aid in the recognition of steroid hormone-producing tumors and may be particularly useful in the diagnosis of adrenocortical carcinoma. The presence of immunoreactivity for A103 practically excludes any other carcinoma that may enter into the differential diagnosis of adrenocortical tumors.

Prenatal diagnosis and carrier detection for glycogen storage disease type III using polymorphic DNA markers

Deficiency of glycogen debranching enzyme gene (AGL) causes glycogen storage disease type III (GSD-III), an autosomal recessive disease. Prenatal diagnosis and carrier detection using enzymatic methods are technically difficult and have limited ability to distinguish a carrier from an affected patient. Mutations in the AGL gene can be used for these purposes. However, the mutations identified thus far account for less than half of the total mutant alleles, and no common mutations have been detected except in North African Jews and in a rare subtype of the disease (GSD-IIIb). Our recent identification of three highly informative DNA polymorphic markers in the AGL gene allowed us to perform prenatal diagnosis and carrier detection in two GSD-III families with unknown mutations, using the polymerase chain reaction (PCR) and restriction analysis. In one family, a fetus was diagnosed to be a GSD-III carrier and his carrier status was confirmed postnatally. A newborn in the second family was postnatally diagnosed with the disease.

Quantitative analysis of antibiotics by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Comparative studies of the matrix-assisted laser desorption/ionization (MALDI) of 30 antibiotics were made using alpha-cyano-4-hydroxycinnamic acid (HCCA), 2,5-dihydroxybenzoic acid (DHB), 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphyrin and meso-tetra(N-methyl-4-pyridyl)porphyrin matrices. Most antibiotics generated intense protonated molecules in HCCA and DHB matrices, and sodium or potassium adduct ions in porphyrin matrices. Using sulfonamide antibiotics as model compounds, DHB was found to be the most suitable matrix for quantitative analysis. Detection limits were about 1 picomole. Linear correlation (R2 > 0.97), between the sample quantity over the range 1 to 100 picomole and the signal response, was obtained when ratios of the sum of peak areas of protonated molecules and sodium adduct ions, with reference to that of a structurally analogous internal standard (acetaminophen), were measured. The precision was found to be in the range of 4 to 32% relative standard deviation, dependent on the type and concentration of the analyte. A simple acylation derivatization process was developed to confirm the presence of suspected antibiotic residues. It is demonstrated that MALDI is a viable technique for the quantitative analysis of low molecular weight antibiotics.

Molecular cloning of acid alpha-glucosidase cDNA of Japanese quail (Coturnix coturnix japonica) and the lack of its mRNA in acid maltase deficient quails

Acid alpha-glucosidase (GAA) hydrolyzes alpha-1, 4 and alpha-1, 6 glucosidic linkages of oligosaccharides and degrades glycogen in the lysosomes. The full-length GAA I cDNA, pQAM8, was isolated from a cDNA library derived from Japanese quail liver. The cDNA is 3569 base pairs long and has an open reading frame capable of coding 932 amino acids. The deduced amino acid sequence shares 52% identity with human GAA. Transfection of expression vector pETAM8 into COS-7 cells or acid maltase deficient (AMD) quail embryonic fibroblasts increased the level of GAA 20-50-fold. Compared to normal quail, the levels of GAA I mRNA were significantly reduced in the muscle, liver, heart, and brain of AMD quails, suggesting the GAA deficiency in AMD quail is due to a lack of GAA I mRNA. A second GAA II cDNA was identified after probing the cDNA library from the ovarian large follicles of quails with a PCR product derived from cultured quail skin fibroblasts. This clone having 3.1 kb insert, has GAA activity as well (3 to 10 fold increase). This cDNA, designated GAA II, predicted an 873 amino acid polypeptide showing 63% identity to human GAA and 51% identity to the GAA I. The RT-PCR analysis demonstrated that GAA II mRNAs were barely detectable in normal tissues, while they were enhanced to higher levels in AMD tissues. These results suggest that GAA II expression is up-regulated at the transcription levels, and quail GAA gene redundancy performs the same function of satisfying GAA demand at the two different phases represented by normal and AMD.

MHC class I and II expression in prostate carcinoma and modulation by interferon-alpha and -gamma

BACKGROUND

Expression of Major Histocompatibility Complex (MHC) class I and II antigens are critical for the cellular immune response. Loss of MHC expression represents one mechanism by which cancer cells escape immune recognition.

PURPOSE

To define MHC class I and II expression by prostate cancer (PCa) in vivo and in vitro and the ability to modulate MHC expression in vitro with IFN-alpha and -gamma.

METHODS

Frozen tissue sections of 25 benign prostatic hyperplasia (BPH) and 18 PCa specimens were studied by immunohistochemistry. PCa cell lines LNCaP, PC-3, and DU-145 were studied by FACS, ELISA, and cytospin. Class I was detected by monoclonal antibody (mAb) W6/32, and class II by mAb 13.17. The effects of IFN-alpha and -gamma were assessed by testing the three cell lines in the presence or absence of varying concentrations of the cytokine for varying incubation times.

RESULTS

Class I was strongly expressed by 24/25 BPH specimens; 4/18 (22%) PCa were homogeneously class I-positive, while 5/18 (28%) were heterogeneously positive and 9/18 (50%) were class I-negative. PC-3 and DU-145 expressed normal levels of class I, while LNCaP expressed only low levels. All line except LNCaP demonstrated significant up-regulation of class I with either IFN-alpha or -gamma. Class II expression was not seen in BPH epithelium nor in 17/18 PCa. Class II could be only weakly induced in the three PCa lines.

CONCLUSIONS

These findings confirm prior studies demonstrating that class I expression is commonly lost or diminished in PCa. In addition, class II up-regulation by IFN-gamma appears very limited in relation to other normal or neoplastic epithelium.

IMPLICATIONS

The present findings, taken together with previous studies, are most consistent with the expression of neoantigens by PCa, which are recognized and appropriately eliminated by the cellular immune system. This selective pressure favors outgrowth of cells which down-regulate or lose class I and/or class II expression. Understanding PCa immunobiology will help in the development of effective immunotherapy for this disease.

SSX: a multigene family with several members transcribed in normal testis and human cancer

Analysis of t(X;18) translocation in synovial sarcoma had previously led to the definition of the SSX2 gene, the fusion partner on chromosome X. Subsequent screening of testicular cDNA libraries identified 2 highly homologous genes, SSX1 and SSX3. Among these 3 genes, SSX2 has been found to be identical to HOM-MEL-40, which codes for an immunogenic tumor antigen expressed in various human cancers. SSX2 thus belongs to the family of cancer/testis (CT) antigens, i.e., immunogenic protein antigens with characteristic mRNA expression in normal testis and in cancer. To define additional CT antigens, we have immuno-screened a testicular cDNA expression library with an allogeneic serum from a melanoma patient, and both SSX2 and SSX3 were isolated. Further studies using testicular cDNA and SSX probes defined 2 new members of this gene family, SSX4 and SSX5, while a shorter cDNA variant of SSX4 was also identified. All 5 members of the SSX family shared strong sequence homology, with nucleotide homology ranging from 88 to 95% and amino acid homology ranging from 77 to 91%. Genomic cloning of a prototype SSX gene (SSX2) showed that its coding region is encoded by 6 exons, and the shortened form of SSX4 cDNA represents an alternatively spliced product lacking the 5th exon. Analysis of SSX mRNA expression by gene-specific RT-PCR confirmed that all 5 SSX genes are expressed in testis. In addition, analysis of a panel of 12 melanoma cell lines showed strong mRNA expression of either SSX1 (3/12), SSX2 (3/12), SSX4 (1/12), or SSX5 (1/12), indicating variable activation of the genes in malignant cells.