Atypical isoenzymes of PKC-iota, -lambda, -mu: relative distribution in mouse foetal and neonatal organs

PKC-iota, -lambda and -mu are recently cloned and characterized as members of the alternative group of this family of protein kinases. We performed an immunohistochemical study about the expression of PKC-iota, -lambda and -mu in tissues and organs of mouse foetuses and newborn mice, in order to evaluate their peculiar functions during the developmental stages. The specificity of the antibodies was tested by Western-blotting experiments with whole extracts from 15-day mouse foetuses or neonatal mice. Cryostat sections of mouse foetal and neonatal organs were reacted with monoclonal (anti -iota and -lambda) or polyclonal (anti -mu) antibodies. The staining intensity was expressed in standardized arbitrary units from 0 to 250. An almost general increasing expression from foetal to neonatal samples, with the highest immunostaining for PKC-mu, was observed in all investigated organs, thus suggesting that PKC atypical isoforms are quantitatively expressed with a significant relationship with the proceeding of developmental phases. Marked differences were revealed also as far as the distribution of these isoforms was concerned in well defined cell populations, particularly in lung, stomach and kidney. These results suggest that various cell populations, in important phases of proliferating and differentiating events, produce atypical PKC isoforms that are conceivably involved in regulating signal transducing events. Therefore, PKC-iota, -lambda, -mu isoforms may have well defined functions in regulating the growth or the program of cell proliferation and differentiation.     

Isolation of high affinity antibodies to streptococcal group A polysaccharide reacting with thymus and cutaneous epithelial cells

Anti-streptococcal A polysaccharide (anti-A polysaccharide) antibodies were isolated from sera of rabbits immunized with group A streptococci by means of immunosorbents. The antibodies were studied by indirect immunofluorescence method on sections of skin and thymus tissues. Most preparations of high affinity antibodies reacting with A polysaccharide in the immunodiffusion test also react with skin and thymus epithelial cells. No preparations of low affinity anti-A polysaccharide antibodies reacted with thymus or skin epithelium. It was found that the reaction of antibodies to A-polysaccharide with epithelial cells does not depend on the availability of antibodies cross reacting with group L streptococcal polysaccharide. The reaction with thymus and skin epithelial cells is likely to be bound with high affinity antibodies to the specific determinant of A-polysaccharide.     

Immunohistochemical localization of glucose transporters and insulin receptors in human fetal membranes at term

The localization has been investigated of the isoforms GLUT1, GLUT3 and GLUT4 of glucose transporter proteins as well as of insulin receptors. Fetal membranes (n = 10) were examined by immunohistochemical methods at the light and electron microscopic levels using mono- and polyclonal antibodies. In all amnion epithelial cells, GLUT1 and GLUT3 antibodies were bound to the apical membrane. Very rarely the GLUT1 antibody also immunostained the basolateral membrane and reacted weakly with the endomembrane system and membranes of the lateral cell protrusions. Fibroblasts reacted with the antibodies against GLUT1, GLUT4 and insulin receptor, whereas they were labelled only in one case with GLUT3 antibody. Cytotrophoblast cells were only stained with antibodies against GLUT1 and GLUT3. Antibodies against GLUT4 only reacted with fibroblasts in the membranes. On amnion epithelial cells, weak immunoreactivity with insulin receptor antibodies was detected only at the electron microscopic level. The data indicate: (1) GLUT1 is located on all cells of the amnion, whereas GLUT3 is present in detectable amounts only on amnion epithelial cells and cytotrophoblast; (2) GLUT1 and GLUT3 on amnion epithelial cells are predominantly located on the apical surface; (3) GLUT4 and insulin receptors are not regularly expressed. We suggest that amnion epithelial cells cover their basal glucose requirements from the amniotic fluid and not from the maternal circulation.     

Ultrastructural localization of nonstructural and coat proteins of 19 potyviruses using antisera to bacterially expressed proteins of plum pox potyvirus

Antisera to the bacterially expressed nonstructural proteins (NSP) HC-Pro, CI, NIa, and NIb and the coat protein (CP) of plum pox potyvirus (PPV) were used for analysing the composition of virus-induced cytoplasmic and nuclear inclusions by electron microscopy. The antisera reacted with NSP and CP of PPV on immunogold-labelled ultrathin sections. Antiserum to CP reacted with virions of seven out of 18 other potyviruses. CP was distributed throughout the cytoplasm of infected cells. Antisera to PPV NSP specifically reacted with virus-specific cytoplasmic and/or nuclear inclusions induced by 17 different potyviruses. NSP were furthermore localized in confined cytoplasmic areas in between complex accumulations of virus-specific inclusions. Cylindrical inclusions induced by the potyviruses were proven to consist of CI protein. Most other cytoplasmic or nuclear inclusions were shown to be composed of two or more NSP. An unexpected composition of virus-induced inclusions was observed for the crystalline nuclear inclusions of tobacco etch virus. Here, in addition to the expected presence of NIa and NIb, HC-Pro could be demonstrated. Furthermore, amorphous cytoplasmic inclusions induced by papaya ringspot virus contained the expected HC-Pro but additionally NIa, NIb and CI. Beet mosaic virus-induced nuclear inclusions ('satellite bodies') contained in their electron-dense matrix NIa, NIb, Hc-Pro and CI and in their lacunae CP in bundles of virion-like filaments. The results indicate that all cytoplasmic or nuclear inclusions of potyviruses have to be regarded as deposition sites of excessively produced viral NSP.     

Reactivity of antibody YU-311 in formalin-fixed, paraffin-embedded specimens of normal organs, non-hematopoietic tumors, and mast cell tumors

YU-311 is a monoclonal antibody that reacts with a human leukemia cell line resistant for cytosine arabinoside and that identifies a 92 kDa membrane protein. The reactivity of YU-311 in normal organs, various non-hematopoietic tumors and in mast cell tumors in formalin-fixed, paraffin-embedded specimens was examined using immunohistochemical methods. In normal organs, YU-311 reacted with fundic glands of the stomach, the intercalated duct of the pancreas, the distal portion and the loop of Henle of renal tubules and tissue mast cells. Benign neoplasms of various organs showed no immunoreaction with YU-311, except for mast cell tumors. Some types of malignant neoplasms were occasionally positive against YU-311, suggesting neoplasms arising from or differentiating along normal YU-311-positive counterparts. Some other types of malignancies were rarely positive for YU-311, although their normal counterparts showed no immunoreactivity with YU-311. None of the non-epithelial tumors reacted with YU-311, except for one case of malignant melanoma. In contrast, normal tissue mast cells and their related tumors, such as urticaria pigmentosa or solitary mastocytoma, were constantly positive for YU-311. None of the non-hematopoietic human tumor cell lines examined in the present study was reactive with YU-311. These findings indicate that YU-311 is a good marker of some types of tumors and mast cell tumors and that an aberrant expression of YU-311 rarely occurs.     

Immunohistochemical distribution pattern of intermediate filament proteins and muscle actin in feline and human mammary carcinomas

Thirty-seven feline and 38 human spontaneous mammary gland carcinomas were studied immunohistochemically. Commercially available antibodies directed against high and low molecular weight keratins (RCK-102 and NCL-5D3), vimentin, desmin, glial fibrillary acidic protein (GFAP), neurofilament (NF) proteins and muscle actin (HHF35) were used in the avidin biotin peroxidase complex (ABC) technique on formalin-fixed paraffin wax-embedded tumour tissue samples. Healthy feline and human mammary gland tissue adjacent to the neoplasms was also examined. The distribution pattern of intermediate filament proteins and muscle actin was comparable in healthy mammary gland tissue of the two species: both RCK-102 and NCL-5D3 antibodies reacted with luminal epithelial cells of ducts and acini, but basal/myoepithelial cells were stained by RCK-102 exclusively. In addition, basal/myoepithelial cells expressed vimentin and muscle actin in both species, and GFAP was found in some feline basal/myoepithelial cells. No immunoreactivity to desmin and NF proteins was observed. Feline mammary gland carcinoma cells reacted with RCK-102 (89%), NCL-5D3 (62%), vimentin (76%) and GFAP (30%) antibodies, while human mammary gland carcinoma cells reacted with RCK-102 (95%), NCL-5D3 (100%) and vimentin (13%) antibodies. HHF35 immunoreactivity was observed in stromal cells only. These results indicate that mammary gland carcinomas of both species share a heterogeneous immunophenotype with respect to intermediate filament proteins, which adds to the list of known similarities between mammary gland carcinomas of both species.     

Lipoprotein profile, diet and body composition in athletes practicing mixed an anaerobic activities

To investigate the prevalence and possible role of anti-endothelial cell antibodies (AECA) in the pathogenesis of systemic lupus erythematosus (SLE), cell membrane antigen was prepared from cultured human umbilical vein endothelial cells and immunoblotting performed to detect AECA in SLE sera. IgG-AECA could be detected in 41 (86%) of 47 SLE patients. They were highly specific and failed to react with membrane antigens of human peripheral blood mononuclear cells or granulocytes. IgG-AECA reacted with endothelial membrane antigens which ranged from 15 to 200 kDa in molecular size. Further analysis of the antigens reacting with IgG-AECA revealed some interesting correlations between specific species of antibodies with certain clinical manifestations. Thus, patients having lupus nephritis, vasculitis, and hypocomplementemia had IgG-AECA against a 66-kDa membrane antigen; those with thrombocytopenia had IgG-AECA against a 55-kDa antigen; those with pleuritis had IgG-AECA against an 18-kDa antigen. These results indicate that IgG-AECA in the sera of SLE patients consist of heterogenous species.     

Species specificity of monoclonal antibodies to human tartrate-resistant acid phosphatase

Tartrate-resistant acid phosphatase (TRAP) is expressed abundantly by osteoclasts and is required for bone resorption. This enzyme is emerging as an important biomarker in bone pathology, both for histochemical identification of osteoclasts and as a serum marker of osteoclast activity and increased bone turnover. Rat and mouse models are becoming popular systems for studying osteoclast development, bone physiology and morphogenesis, and bone diseases such as osteoporosis. We have developed two unique antibodies to human TRAP purified from hairy cell leukemia spleen. Both antibodies (9C5 and 14G6) are suitable for immunohistochemistry of osteoclasts and macrophages. Only one (14G6) is capable of immunoprecipitating active TRAP from human cell lysates. Antibody 9C5 reacts with a denatured epitope of TRAP while antibody 14G6 probably reacts with a native, conformational determinant. The high degree of homology among TRAPs of various species predicts that these antibodies should be suitable for work in experimental animals as well as humans. Immunohistochemical staining, electrophoretic analyses, immunoprecipitation and immunoblotting assays of human rat and mouse TRAP were carried out to test the validity of these antibodies as cell markers in rodents. Both antibodies were suitable for immunohistochemistry in all species. Antibody 9C5 was suitable for immunoblotting of denatured TRAP of all species tested. Antibody 14G6 reacted with the native TRAP of humans only and failed to immunoprecipitate mouse or rat TRAP activity. Although TRAP is a phylogenetically conserved protein, subtle, species-specific determinants exist. Care should be exercised when anti-TRAP antibodies are used for immunoassay in experimental animals.     

Establishing a cancer risk evaluation program

Most of the clinical, histological and immunohistological features of fogo selvagem resemble those of idiopathic pemphigus foliaceus (PF). Both diseases are clinically characterized by small flaccid bullae evolving into to scaly and crusted lesions, sometimes with pustules, mainly in seborrheic areas of the skin. Mucosal surfaces are mostly spared. The main histologic feature of endemic pemphigus foliaceus is a subcorneal acantholytic blister. Standard immunofluorescence studies demonstrate intercellular IgG deposits throughout the entire epidermis. These IgG antibodies are mainly of the IgG4-subclass. Almost all patients have circulating IgG-autoantibodies in their serum directed against stratified epithelial desmosomes. The fogo selvagem autoantibodies and the PF antibodies are directed against the 160 kD desmosomal glycoprotein desmoglein 1 which together with plakoglobin (85 kD) forms a complex of adhesion proteins with desmosomes of stratified epithelia. Fogo selvagem occurs in endemic foci in some areas of Brazil and possibly in neighbouring South American countries, very often in children, adolescents and young adults. The etiology of fogo selvagem is still unknown. The frequent association with insect bites has lead to the concept of fogo selvagem being a transmissible disease with acquired immunity in adulthood. However, the infectious agent and possible vectors have not yet been identified.     

Glycosylation reactions in Plasmodium falciparum, Toxoplasma gondii, and Trypanosoma brucei brucei probed by the use of synthetic peptides

D-type cyclins are necessary and rate-limiting for G1 progression during the mammalian cell cycle. Cyclins D1, D2, and D3 are encoded by distinct genes and are expressed in proliferating cells in a lineage-specific manner. Monoclonal antibodies (mAbs) generated to bacterially produced recombinant D-type cyclins were able to react with the native proteins expressed in mammalian cells. One mouse and three rat mAbs immunoprecipitated cyclin D1 from mouse macrophages. Only rat mAbs reacted with human cyclin D1 and cross-reacted with cyclin D2 expressed in proliferating T lymphocytes and human tumor cell lines. A single rat mAb to cyclin D2 exhibited a pattern of reactivity reciprocal to that of rat mAbs to D1. Three rat mAbs reacted specifically with mouse or human cyclin D3, but did not cross-react with cyclins D1 or D2 from either species. Representative mAbs were useful for immunoblotting and detected D-type cyclins coprecipitating in complexes recovered with antiserum to cyclin-dependent kinase-4 (CDK4). Because these mAbs detect D-type cyclins in the nuclei of fixed permeabilized cells, they should prove useful in documenting cyclin overexpression in those human tumors in which the genes are amplified or are targets of specific chromosomal rearrangements.     

Serological survey to determine the prevalence of bovine leukaemia virus antibodies in dairy cattle on selected farms in the Gauteng and Mpumalanga provinces

Cattle from a farm where enzootic bovine leukosis had been diagnosed were tested to determine the prevalence of bovine leukaemia virus antibodies. Farmers who had bought cattle from this farm were identified and their herds also tested. Of 381 adult dairy cattle tested, 14 animals reacted positively (3.67%). Cattle (n = 81) from 3 selected herds, not associated with the affected farm were also bled and 7 animals reacted positively (8.64%).     

Production of monoclonal antibodies specific to Clostridium botulinum type B neurotoxin

Four monoclonal antibodies were produced for use in a rapid method to detect Clostridium botulinum type B neurotoxin. Cells of mouse myeloma cell line SP2/0 were fused with splenocytes of immunized BALB/c mice. An immunoblot assay of semipurified commercial neurotoxins of C. botulinum types A, B, C, D, E, and F was used to show specificity. All the monoclonal antibodies reacted with type B neurotoxin but did not cross-react with the other types. The monoclonal antibodies, separately and combined, did not neutralize the toxin in mice, and all showed specificity to the whole neurotoxin molecule and the heavy-chain component by immunoblot. No evidence of specific binding to the hemagglutinin molecule was noted. When tested against concentrated cultured supernatants of C. botulinum types A, B, E, and F, the 4 monoclonal antibodies reacted only against type B strains. They will be incorporated into a rapid assay with other specific monoclonal antibodies to detect C. botulinum neurotoxins from pure cultures or suspect foods.     

Role of anti-recoverin autoantibodies in cancer-associated retinopathy

PURPOSE: To examine the retina and test the serum of a patient with cancer-associated retinopathy syndrome who was diagnosed with small cell carcinoma of the lung and experienced unexpected visual loss. METHODS: Proteins from normal human retina were extracted, separated by one- and two-dimensional gel electrophoresis, transferred to PVDF membrane, and used for immunostaining. Antibody specificity was determined by use of solid-phase peptides in a solid-phase immunoassay. RESULTS: Histologic examination of the retina showed loss of the photoreceptor cell layer. This finding correlated with the results of clinical (loss of vision) and electrophysiologic (abnormal electroretinograph [ERG]) tests. The patient's serum antibodies specifically recognized recoverin, a protein predominantly found in retinal photoreceptor cells. The patient's serum also labeled some higher molecular weight proteins present in normal lung and other normal tissues, as well as in lung cell carcinoma cell lines. The only other tissue in which immunoreactivity against p23 could be found was the optic nerve. Our data revealed a lack of cross-reactivity between specific anti-recoverin antibodies and lung proteins. The results indicate that the patient serum contains more than one type of antibody activity. The autoantibodies were tested for fine immunospecificity by use of solid-phase peptides in a solid-phase immunoassay. Patient's antibodies reacted with a major determinant located in the recoverin sequence 62-68 (PKAYAQH) and with several minor ones. CONCLUSION: Based on the fact that the recoverin appears to be distributed in several different cell types, we suggest that this protein may be present in cancer cells and may play a role in the pathogenesis of some cancer-associated retinopathies.     

Sex hormone receptors of hemangiomas in children

The newly identified association of human nonnarcoleptic rapid eye movement (REM) sleep behavior disorder (RBD) with human leukocyte antigen (HLA) DQw1 class II genes raises the possibility that RBD may arise from autoimmune mechanisms. Two recent case reports involving postmortem brain stem histochemical analyses in elderly males with RBD identified severe monoaminergic cell loss in the locus ceruleus (LC). Thus, we designed a study to detect anti-LC antibodies in RBD. Ten Caucasian males (mean age, 66 years) with polygraphically confirmed RBD (n = 5, idiopathic RBD: n = 5, RBD with Parkinson's disease), but without narcolepsy, idiopathic hypersomnia, or autoimmune disease, were recruited for this study, along with 10 Caucasian male controls (mean age, 63 years) without a history of sleep disorder or autoimmune disease. In a blinded design, sera from the RBD patients and their controls were tested against human LC and other brainstem neurons. Brainstem tissue was obtained from autopsies of neurologically normal individuals. The presence of anti-LC antibodies was examined using immunohistochemistry on brainstem sections. Sections incubated with sera from normal individuals and sera from patients with paraneoplastic antineuronal antibodies (anti-Hu and anti-Ri) were used as controls. No reactivity with LC or any other brainstem area was identified with sera from either RBD patients or their controls, or from the other group of normal individuals. In contrast, sera from patients with paraneoplastic anti-Hu and anti-Ri antibodies reacted strongly with nuclei of LC and other brainstem neurons, sparing the nucleoli, and reacted to a lesser extent with the cytoplasm of these neurons. Therefore, it is unlikely that human RBD is associated with anti-LC antibodies. However, an autoimmune process in RBD has not been excluded by this study.     

Immunohistochemical distribution and subcellular localization of three distinct specific molecular structures of advanced glycation end products in human tissues

Using three mouse anti-human monoclonal antibodies for advanced glycation end products (AGEs), 6D12, 1F6, and 2A2, we examined the immunohistochemical distribution and localization of AGEs in various organs and tissues obtained from nondiabetic autopsy or biopsy cases (men and women, 41 to 86 years of age). 6D12 recognizes Nepsilon-(carboxymethyl)lysine (CML), a nonfluorescent and non-cross-linked AGE structure, and 1F6 recognizes fluorolink, a fluorescent and cross-linked AGE structure. The epitope of 2A2 is unknown but is different from that of CML and fluorolink or other known AGE structures such as pyrraline, pentosidine, and crosslines. Immunohistochemistry with these monoclonal antibodies revealed the intra- and extracellular accumulation of AGEs in these organs and tissues. By double immunohistochemical staining with two of the three monoclonal antibodies in different combinations, positive reaction products for all three monoclonal antibodies were demonstrated in macrophages widely distributed in various organs and tissues; endothelial cells of endocardium, arteries, veins, and blood capillaries; mesenchymal cells; epithelial or parenchymal cells; blood cells; and extracellular matrix. This result indicates that these three different AGE-specific molecules are formed intracellularly and extracellularly. In some cell types, however, one or two of these specific molecules were not always found together, suggesting that the molecular structures of AGEs and their formation are heterogeneous. Immunoelectron microscopy demonstrated the localization of AGE-labeled immunogold particles in the nuclei, nuclear envelope, mitochondria, endoplasmic reticula, Golgi complexes, endocytic vesicles, lysosomal vacuoles or granules, secretory granules, cytosol, and cell membranes, as well as in the extracellular matrix. In addition, the double histochemical staining method for ceroid/lipofuscin and immunohistochemistry for AGEs demonstrated intralysosomal formation and accumulation of AGEs in ceroid/lipofuscin pigments. These results suggest that the extracellularly produced AGEs are taken up by receptors into the cells and accumulate in secondary lysosomes and that AGEs are formed intranuclearly and/or intracellularly, probably via different metabolic pathways.     

Expression of cyclin D1 in epithelial tissues of transgenic mice results in epidermal hyperproliferation and severe thymic hyperplasia

To study the involvement of cyclin D1 in epithelial growth and differentiation and its putative role as an oncogene in skin, transgenic mice were developed carrying the human cyclin D1 gene driven by a bovine keratin 5 promoter. As expected, all squamous epithelia including skin, oral mucosa, trachea, vaginal epithelium, and the epithelial compartment of the thymus expressed aberrant levels of cyclin D1. The rate of epidermal proliferation increased dramatically in transgenic mice, which also showed basal cell hyperplasia. However, epidermal differentiation was unaffected, as shown by normal growth arrest of newborn primary keratinocytes in response to high extracellular calcium. Moreover, an unexpected phenotype was observed in the thymus. Transgenic mice developed a severe thymic hyperplasia that caused premature death due to cardio-respiratory failure within 4 months of age. By 14 weeks, the thymi of transgenic mice increased in weight up to 40-fold, representing 10% of total body weight. The hyperplastic thymi had normal histology revealing a well-differentiated cortex and medulla, which supported an apparently normal T-cell developmental program based on the distribution of thymocyte subsets. These results suggest that proliferation and differentiation of epithelial cells are under independent genetic controls in these organs and that cyclin D1 can modulate epithelial proliferation without altering the initiation of differentiation programs. No spontaneous development of epithelial tumors or thymic lymphomas was perceived in transgenic mice during their first 8 months of life, although they continue under observation. This model provides in vivo evidence of the action of cyclin D1 as a pure mediator of proliferation in epithelial cells.     

Species-specificity of monoclonal antibodies recognising Prevotella intermedia and Prevotella nigrescens

Prevotella intermedia and Prevotella nigrescens are not easily distinguished, making it difficult to assess their roles in disease. This study examined the specificity of three monoclonal antibodies (mAbs) for these species. Differentiation between P. intermedia (13 isolates) and P. nigrescens (24 isolates) was by the electrophoretic mobility of their malate and glutamate dehydrogenase enzymes or by DNA homology grouping. All P. intermedia reacted strongly with mAb 40BI3.2.2 whereas P. nigrescens strains did not. Monoclonal antibodies 37BI6.1 and 39BI1.1.2 recognised all strains of both species but most P. nigrescens reacted weakly with mAb 39BI1.1.2. Monoclonal antibody 40BI3.2.2 therefore recognises an antigen specific for P. intermedia but not P. nigrescens and provides an easy and reliable means of distinguishing between these species. Three vaginal isolates identified biochemically as P. intermedia had enzymes with mobilities corresponding to neither P. intermedia nor P. nigrescens. These isolates were not recognised by mAbs 39BI1.1.2 or 40BI3.2.2 and may represent an undescribed taxon within this group of organisms.     

Internalin A can mediate phagocytosis of Listeria monocytogenes by mouse macrophage cell lines

Listeria monocytogenes internalin A (InlA) is a surface protein that mediates the attachment of Listeria to, and invasion of, hepatocytes, epithelial, and endothelial cells. In this study, we tested whether InlA could also mediate phagocytosis of L. monocytogenes by the non-listericidal mouse macrophage cell lines J774A.1 and H36.12j. Recombinant InlA (rInlA) was used to derive mouse monoclonal anti-InlA antibodies (mAb) and rabbit anti-InlA antibodies. Fluorescence microscopy demonstrated that these anti-InlA antibodies reacted with wild-type L. monocytogenes, L. ivanovii, and L. innocua+, a mutant transformed with the inlAB operon that expresses surface InlA but failed to react with Bug 8, an InlA/InlB-negative transposon mutant of L. monocytogenes or with noninvasive Listeria sp. Fluorescence microscopy, radiolabeling, and flow cytometry showed that rInlA bound specifically to both macrophage cell lines. Incubation of macrophages and wild-type L. monocytogenes in the presence of rInlA or pretreatment of Listeria with anti-InlA antibodies specifically inhibited, by at least 50%, the phagocytosis of Listeria by both of these cells. By comparison, treatment with these reagents failed to affect the phagocytosis of Streptococcus pyogenes by either macrophage cell line nor did these reagents alter the ability of macrophages to internalize wild-type L. monocytogenes. We found that Bug 8, but not wild-type L. monocytogenes, failed to grow within both of these non-listericidal macrophage cell lines. In contrast to infection by wild-type L. monocytogenes, Bug 8 was rapidly eliminated from the spleens of both C57Bl/6 and DBA/2 mice. Data presented here show that only invasive Listeria sp. have surface InlA and that L. monocytogenes can enter non-listericidal macrophage cell lines by binding of bacterial InlA to the macrophage cell surface.     

A comparative immunohistochemical study of pancreatic islets in laboratory animals (rats, dogs, minipigs, nonhuman primates)

The aim of the present study was to distinguish and describe the patterns of distribution of pancreatic islets within the pancreas of four species of laboratory animals, including rats, dogs, minipigs and monkeys, and furthermore, to identify immunohistochemically various islet cell types and characterize their content. Histopathological examinations were performed on sections stained with hematoxylin and eosin (H&E) and immunostained using rabbit polyclonal antibodies (pAb) against insulin, glucagon, pancreatic polypeptide (PP), somatostatin, chromogranin A, keratin, bombesin and gastrin, or mouse monoclonal antibodies (mAb) against synaptophysin, Leu-7 and proliferating cell nuclear antigen (PCNA) in three-step rabbit immunoperoxidase (PAP) and streptavidin/peroxidase (StreptABC/HRP) reactions. Positive immunohistochemical reactions were observed in the pancreatic islets of all animal species with all antibodies, except with anti-bombesin and anti-gastrin antibodies. Our results revealed that: 1) there is species specific regional arrangement of islets in the pancreas, 2) each species presents a characteristic distribution of cells producing different hormones. 3) immunoreactivity with immunohistochemical markers varies between species and/or age. The present comparative immunohistochemical study could be helpful for answering questions which are important for understanding some of the intricate mechanisms that govern the integrated function of the endocrine pancreas.     

The use of chicken-specific antibodies in veterinary research involving three other avian species

In this study we investigated a panel of 20 polyclonal and monoclonal antibodies specific for chicken cells and tissues for cross-reactivity with other avian species, i.e. turkey, duck and quail, using immunoperoxidase staining on cryostat sections. The number of cross-reacting antibodies was highest for turkey (12/20) and quail (10/20) and lowest for duck (5/20), reflecting the phylogenetic distance between these birds. In ducks only antibodies specific for mononuclear phagocytes and for stromal molecules in mesenchym, muscle cells, endothelial, and epithelial cells cross-reacted. In turkeys and quails cross-reaction was seen with antibodies against T-helper lymphocytes, IgM- and IgG-positive B cells and plasma cells, and mononuclear phagocytes. In addition, most antibodies specific for stromal molecules reacted against turkey or quail molecules. The panel of reacting antibodies can be used for research into the natural and specific defence mechanisms of turkeys and quails.