Myocardial tissue characterization by autocorrelation of two-dimensional ultrasonic backscatter

To evaluate a novel method for determining the spatial distribution of echocardiographic information based on the two-dimensional autocorrelation function, echocardiographic images were obtained from specific regions of interest from 10 healthy volunteers, seven patients with genetically defined hypertrophic cardiomyopathy, and nine patients with pressure-overload hypertrophy. The wavelength of distinct peaks from the two-dimensional autocorrelation of the images was compared between groups of patients and demonstrated a significant decrease in the mean length scale associated with distinct secondary correlation peaks in patients with hypertrophic cardiomyopathy or pressure-overload hypertrophy compared with healthy volunteers (p = 0.0009). With a discriminating wavelength of 3.3 mm, the sensitivity of this technique for detecting abnormal myocardium was 84% with a specificity of 89%. This study suggests that ultrasonic tissue characterization based on the two-dimensional autocorrelation function may have potential for distinguishing normal from abnormal myocardium and provides a rationale for textural approaches to ultrasonic tissue characterization.

Interleukin-1 receptor expression by ovine afferent lymph dendritic cells: response to secondary antigen challenge

Interleukin (IL)-1 is thought to enhance the function of antigen presenting cells of the dendritic cell lineage. To investigate the interaction of IL-1 and dendritic cells recombinant ovine IL-1 alpha and IL-1 beta have been used to determine IL-1 receptor (R) expression on fresh dendritic cells (ALDC) collected from cannulated sheep pseudoafferent lymph ducts, both prior to and in response to localized ovalbumin challenge. Resting ovine ALDC express approximately 510 IL-1R per cell for IL-1 alpha (Kd approximately 30 pM) and approximately 350 IL-1R/cell for IL-1 beta (Kd approximately 160 pM). Saturation binding and in situ analyses show an initial transient but dramatic increase in IL-1 alpha binding to ALDC by 4 h in response to ovalbumin challenge of primed sheep. Maximal IL-1R expression, reaching > or = 21700 IL-1R/cell for IL-1 alpha detected by around 48 h, was followed by a gradual return to resting level by 8 days post challenge. Fewer than 0.5% of resting ALDC expressed IL-1R but at least 5% of ALDC bound IL-1 alpha after ovalbumin challenge. There was no evidence of specific up-regulation of receptors for IL-1 beta on these cells. Fresh ovine alveolar macrophages, used as a positive control for specific IL-1R expression, were found to express approximately 2600 sites/cell for IL-1 alpha (Kd approximately 56 pM) and 16,500 sites/cell for IL-1 beta (Kd approximately 4.6 pM). In view of the differing IL-1 binding characteristics displayed by the receptors on the two cell types, it is postulated that afferent lymph dendritic cells and macrophages are not expressing the same form of IL-1R.

Evidence for the expression of two distinct MHC class II DR beta like molecules in the sheep

This study used monoclonal antibodies to sheep MHC class II molecules as well as an L cell transfectant (T8.1) which expresses DRA and DRB genes to show that two distinct DR beta chains are expressed in the sheep. Two anti-beta chain specific monoclonal antibodies VPM37 and VPM43 react with DR antigen but not DQ antigen by ELISA. These two antibodies do not react with the DR beta chain expressed in the T8.1 cell line. Two-dimensional immunoblotting shows that these antibodies recognize a subgroup of the spots recognized by the DR-specific monoclonal antibody VPM57 which does react with the T8.1 beta chain. Amino-terminal sequence analysis of the alpha chain associated with VPM37 beta chain shows that this alpha chain is homologous to the human DR alpha chain strongly indicating that the beta chain is DR-like. VPM37 and VPM43 are shown to be directed against different epitopes on sheep MHC class II molecules so it is highly unlikely that the data can be explained by the presence of post-translational modifications or the existence of a very common allele. These data provide clear evidence for the expression of two distinct DR beta chains in the sheep.

Classification and localisation of carcinoembryonic antigen (CEA) related antigen expression in normal oesophageal squamous mucosa and squamous carcinoma

Using a panel of carcinoembryonic antigen (CEA) related antibodies in normal oesophageal squamous mucosa CEA expression is present on suprabasal squames localised to the cell membrane. Immunoblotting shows that this positivity is predominantly due to a glycoprotein of around 180 kDa representing CEA itself. Positivity in squamous carcinomas is confined to cells in foci of squamous differentiation. A shift from membranous localisation to predominant cytoplasmic overexpression is shown between normal and malignant squames using confocal microscopy. The recognition of an adhesive role for CEA and a role in enhancing distant metastases in those tumours expressing CEA highlights the importance of recording CEA expression and changes in subcellular distribution between normal and malignant tissues; CEA expression in oesophageal squamous mucosa has not been well recognised previously and changes in expression may prove of great significance in the spread and dissemination of squamous carcinoma.

Improved discrimination of bovine class II DR beta-chains polymorphisms using immunoblotting

An immunoblotting technique is reported that reveals electrophoretic variants in the beta-chains of class II antigens of the bovine major histocompatibility complex. One monoclonal antibody, mAb VPM57, reacted on immunoblots with an epitope present in approximately half of the haplotypes investigated. This reagent is especially useful in discriminating electrophoretic variants that have similar isoelectric points.

BoLA class I charge heterogeneity reflects the expression of more than two loci

Internationally recognized allo-antisera in lymphocyte microcytotoxicity assays are thought to detect allelic products of a single highly polymorphic class I locus. A recent report suggested that two bovine lymphocyte antigen (BoLA) class I loci are expressed at the protein level. However, 1D-IEF analysis of BoLA class I molecules reveals multi-band patterns which cannot be reconciled with the reported number of loci. The aim of this study was to investigate the origins of the charge diversity of BoLA class I molecules observed using 1D-IEF. BoLA class I molecules appear to be glycosylated at a single N-linked position with a complex type carbohydrate moiety which has up to three terminal sialic acid residues. Class I molecules immunoprecipitated from resting bovine PBL are not phosphorylated. Neither modification is responsible for the observed charge heterogeneity. Peptide mapping reveals that different BoLA charge variants have distinct digestion patterns. Furthermore, a number of different polypeptides are associated with each serological specificity. These polypeptides appear to be encoded by different loci which exist in linkage disequilibrium. The number of charge variants with different peptide maps indicates that the BoLA system has a minimum of three class I loci expressed at the protein level.

Classification of CEA-related positivity in primary and metastatic malignant melanoma

Using a panel of antibodies to carcinoembryonic antigen (CEA), in paraffin-processed biopsy material patchy, predominantly membranous positivity was seen on tumour cells in 70 per cent of cases of superficial spreading melanoma, 60 per cent of nodular melanomas, and 75 per cent of secondary deposits studied with unabsorbed polyclonal anti-CEA only. No staining was seen using monoclonal anti-CEAs. Localization of CEA to the cell membrane was confirmed with confocal microscopy. Immunoblotting of fresh frozen material detected CEA of around 180 kD in both primary and metastatic melanomas migrating with an apparent molecular weight of between 150 and 200 kD, indicating variable glycosylation of the protein. Recognition of an adhesive role for CEA with roles in immunolocalization and immunotherapy emphasizes the importance of more precise classification of CEA-related positivity in human tumours.

A critical review of the optimum duration of chronic rodent testing for the determination of non-tumourigenic toxic potential: a report by the BTS Working Party on Duration of Toxicity Testing

This review indicates that for the detection of non-neoplastic toxic effects: 1. Four decades of accumulated literature provide no lead as to the optimum duration of repeat dose toxicity testing required for all classes of chemicals, although 6 months repeated administration appears adequate for pharmaceuticals. 2. Three month studies predicted the 2 year outcome for 70% of the compounds evaluated in this pilot study using data published by the US National Toxicology Program. 3. In spite of the limitations of this pilot study, this finding is considered encouraging as it is close to that generated previously on more detailed confidential pharmaceutical data. This suggests that the exercise should now be expanded using confidential surveys of industrial data to determine the concordance resulting from the evaluation of a larger group of chemicals.

Cross-reactivity of workshop antibodies with cells from domestic and wild ruminants

Reactivities of the monoclonal antibodies (mAbs) from the workshop panel with cells from cattle, sheep, goats, Cape buffalo (Syncerus caffer) and waterbuck (Kobus defassa) were tested. One hundred and sixty-nine mAbs reacted with bovine cells and 111 with sheep cells; 86 were shown to react with goat cells, 71 with buffalo cells and 70 with waterbuck cells. Some mAbs cross-reacted with all five ruminants tested, and are likely to react with epitopes that are conserved in other ruminant species. Such mAbs will obviate the need to produce mAbs panels to leukocyte antigens of other ruminants.

Patterns of major histocompatibility complex class II expression by T cell subsets in different immunological compartments. 2. Altered expression and cell function following activation in vivo

This study characterizes antigen-induced phenotypic and functional aspects of major histocompatibility complex (MHC) class II expression on recirculating T cells in efferent lymph. In vivo secondary, but not primary challenge is associated with both kinetic and phenotypic alterations in class II expression by T cells. All three major T cell subsets, CD4+, CD8+ and T19+ (gamma delta T cell receptor), show an approximate four fold increase in the level of MHC class II expression during secondary responses. No changes in B cell expression of class II were seen. Resting efferent lymph T cells are predominantly either class II- or DR+DQ- but this changes to DR+DQ+ after antigenic challenge. The antigen-presenting function of these class II+ T cells was investigated at daily intervals after in vivo antigenic challenge. T cells from non-activated lymph nodes could not induce proliferation of antigen-specific T cells with soluble antigen but were weakly stimulatory in allo-mixed lymphocyte reaction (MLR) at high (> 2:1) stimulator cell ratios. Activated T cells isolated during secondary in vivo responses, and expressing increased quantities of MHC class II, were positive stimulator cells in the MLR. In contrast these cells could not present soluble antigen or trypsin-digested antigen to the T cell lines. In the MLR assays, the relative stimulation by class II+ T cells correlates with the levels of class II expression. We conclude from these experiments that both quantitative and qualitative changes in MHC class II, induced on T cells under physiological conditions, play a role in the regulation of the immune response in vivo but that that role is not simply one of presentation of soluble antigen.

Analysis of the monoclonal antibodies comprising WC6

The WC6 antibovine monoclonal antibodies (mAbs) CC98, IL-A114 and IL-A53 were investigated for reactivity in sheep by (fluorescence activated cell sorting) FACS analysis, immunoprecipitation and immunohistology. The mAbs behave identically by all criteria although IL-A114 reacts more weakly than the other mAbs. This probably reflects limited cross-species reactivity. The mAbs stain < 30% of lymphocytes from blood, efferent and afferent lymph and the majority of afferent lymph dendritic cells. They also weakly stain granulocytes. They precipitate molecules of apparent molecular weight 220 kD and 180-190 kD. Sequential immunoprecipitation shows that CC98 antigen is not related to CD45. Immunohistology indicates staining of B cell areas and macrophages in Peyer's patch and lamina propria. The data show that these monoclonal antibodies react with a molecule distinct from OvCD45R.

Comparison of workshop CD45R monoclonal antibodies with OvCD45R monoclonal antibodies in sheep

The reactivity of the antibovine monoclonal antibodies (mAbs) comprising temporary cluster TC1 was compared with that of two OvCD45R mAbs on sheep cells. Three of the mAbs--CC31, CC99 and CC103--did not cross-react with sheep cells. All the workshop mAbs precipitated two molecules of apparent molecular weight (MW) 200 kDa and 220 kDa while the antisheep CD45R mAb 20-96 precipitated a single band of 220 kDa. Cell surface expression was examined by single colour FACS (fluorescence activated cell sorting) analysis of efferent and afferent lymph cells and peripheral blood lymphocytes and the distribution of the antigens on CD4+, CD8+ and T19+ (WC1) and B cells was determined by two colour fluorescence staining. By cellular distribution and immunohistology the TC1 mAbs could be divided into four distinct groups which differed from a fifth group comprising the two OvCD45R antibodies.

Reactivity of the CD11/CD18 workshop monoclonal antibodies in the sheep

The anti-CD11/CD18 monoclonal antibodies (mAbs) submitted in the Second International Workshop on Ruminant Leukocyte Differentiation Antigens, were analysed for their reactivity with the ovine homologue of CD11/CD18. Their reactivity was tested on healthy sheep tissues, and alveolar macrophages, afferent dendritic cells, peripheral blood granulocytes and monocytes. The CD11a/CD18 mAbs found positive in the sheep were reactive with all the cell populations tested. The CD11b mAbs reacted with all the cells except afferent dendritic cells, whereas CD11c were non-reactive to blood granulocytes. This is in contrast to humans and cattle where blood granulocytes express CD11c. The mAbs 72-87, F10-150, MD2B7 and MUC76A were found to be homologous to CD11a whereas BAQ30A seemed to be homologous to CD18, instead of proposed initial specificity to CD11a. CC125 and IL-A15 mAbs were found to be homologous to CD11b. OM1, which clustered with a recognized CD1 mAb in the first cluster analysis, precipitated a heterodimer of molecular weight 95,000/150,000. We propose that OM1 reacts with sheep CD11c. The mAb MF14B4 was found to react with sheep CD18.

Patterns of major histocompatibility complex class II expression on T cell subsets in different immunological compartments. 1. Expression on resting T cells

In this study we have investigated the expression of major histocompatibility complex (MHC) class II molecules on T cells from various lymphoid compartments in the sheep. Monoclonal antibodies which react specifically with sheep MHC class II molecules homologous to the human DQ and DR molecules have been characterized. These antibodies have been used, together with the monoclonal antibodies specific for sheep CD4-, CD8- and T19-positive T cells, to quantitate DQ and DR expression on T cell subsets in adult and fetal peripheral blood, afferent lymph, lymph node and efferent lymph. The results show that expression of class II by T cells depends on the age of the animal and the physiological location of the T cell. In fetal blood there is no expression of class II on CD8+ or T19+ cells and very low expression on CD4+ T cells. In adult peripheral blood and efferent lymph a significant proportion of cells express DR but not DQ. A very different situation is found in afferent lymph and the peripheral lymph node: in afferent lymph the majority of T cells in all three subsets express both DQ and DR molecules; in the lymph node over 50% of T cells express DR and 30% are DQ+. These results suggest that within all T cell subsets there is a progression from DQ-DR- to DQ-DR+ and DQ+DR+ which correlates with physiological stages of T cell differentiation in vivo.

Early events in immune evasion by the lentivirus maedi-visna occurring within infected lymphoid tissue

Infections caused by lentiviruses, including human immunodeficiency virus, are characterized by slowly progressive disease in the presence of a virus-specific immune response. The earliest events in the virus-host interaction are likely to be important in determining disease establishment and progression, and the kinetics of these early events following lentiviral infection are described here. Lymphatic cannulation in the sheep has been used to monitor both the virus and the immune response in efferent lymph after infection of the node with maedi-visna virus (MVV). Viral replication and dissemination could be detected and consisted of a wave of MVV-infected cells leaving the node around 9 to 18 days postinfection. No cell-free virus was recovered despite the fact that soluble MVV p25 was detected in lymph plasma. The maximum frequency of MVV-infected cells was only 11 in 10(6) but over the first 20 days of infection amounted to greater than 10(4) virus-infected cells leaving the node. There was a profound increase in the output of activated lymphoblast from the lymph nodes of infected sheep, characterized by an increased percentage of CD8+ lymphoblasts. All of the CD8+ lymphoblasts at the peak of the response expressed both major histocompatibility complex class II DR and DQ molecules but not interleukin-2 receptor (CD25). The in vitro proliferative response of efferent lymph cells existing the node after challenge with MVV to both recombinant human interleukin-2 and the mitogen concanavalin A was decreased between days 8 and 16 postinfection, and a specific proliferative response to MVV was not detected until after day 15. Despite the high level of CD8+ lymphoblasts in efferent lymph, direct MVV-specific cytotoxic activity was demonstrated in only one of the five MVV-challenged sheep. MVV-specific antibody responses, including neutralization and MVV p25 immune complexes in efferent lymph, were detectable during the major period of virus dissemination. The relationship of these findings to the evasion of the host's acute immune response by MVV is discussed.

Effect of caffeinated coffee on running speed, respiratory factors, blood lactate and perceived exertion during 1500-m treadmill running

Using a motorized treadmill the study investigated the effects of the ingestion of 3 g of caffeinated coffee on: the time taken to run 1500 m; the selected speed with which athletes completed a 1-min 'finishing burst' at the end of a high-intensity run; and respiratory factors, perceived exertion and blood lactate levels during a high intensity 1500-m run. In all testing protocols decaffeinated coffee (3 g) was used as a placebo and a double-blind experimental design was used throughout. The participants in the study were middle distance athletes of club, county and national standard. The results showed that ingestion of caffeinated coffee: decreases the time taken to run 1500 m (P less than 0.005); increases the speed of the 'finishing burst' (P less than 0.005); and increases VO2 during the high-intensity 1500-m run (P less than 0.025). The study concluded that under these laboratory conditions, the ingestion of caffeinated coffee could enhance the performance of sustained high-intensity exercise.

Cell phenotypes in the efferent lymph of sheep persistently infected with Border disease virus

The prefemoral efferent lymphatics of sheep persistently infected (PI) with Border disease virus (BDV) were cannulated in order to study the effects of the virus on cells of the immune system. Efferent lymphocytes recovered from PI sheep were phenotyped using a panel of monoclonal antibodies (MoAb) specific for ovine cell-surface markers and compared to lymphocytes recovered from normal, healthy controls. PI sheep had an increased percentage of cells expressing the T cell-associated molecules CD5, CD4, CD8 and T19, also an increase in cells expressing CD1 and a population of cells expressing low levels of the T19 molecule which was not present in control sheep. The lymphocytes were examined for the presence of BDV using virus-specific MoAb. On average 8.5% of the efferent lymphocytes from PI sheep carried virus antigen. BDV antigen was also found in the mononuclear cells and connective tissue of lymph nodes indicating widespread virus dissemination within the lymphoid system of PI sheep.

Plasma and serum von Willebrand factor antigen concentrations in connective tissue disorders

Concentrations of serum and plasma von Willebrand factor antigen were measured in over 200 patients with a variety of connective tissue diseases, and in control samples from over 200 asymptomatic individuals. This comprehensive study found the highest concentrations of von Willebrand factor antigen in patients with vasculitis, Sjögren's syndrome, Felty's syndrome, giant cell arteritis and polyarteritis nodosum. Raised values were also found in rheumatoid arthritis, systemic lupus erythematosus, polymyalgia rheumatica, systemic sclerosis, Raynaud's syndrome, Takayasu's arteritis and Wegener's granulomatosis, but not in oesteoarthritis. It is possible that the difference in von Willebrand factor antigen concentrations in two sub-groups of systemic necrotising arteritis (Wegener's granulomatosis and polyarteritis nodosum) may imply different disease processes. The large numbers involved have allowed us to confirm or question smaller studies of the role of this molecule in connective tissue disease.

Characterization of the binding site for nevirapine (BI-RG-587), a nonnucleoside inhibitor of human immunodeficiency virus type-1 reverse transcriptase

Nevirapine (BI-RG-587) is a potent and specific non-nucleoside inhibitor of human immunodeficiency virus type-1 reverse transcriptase. The compound is non-competitive with respect to template, primer, and nucleoside triphosphates indicating that BI-RG-587 does not act directly at the catalytic site. The binding site for this inhibitor was investigated by employing an azido photoaffinity analogue, BI-RJ-70, to covalently label the enzyme. The resulting photoadduct was subjected to enzymatic digestion by trypsin and endoproteinase lys-C and a single, highly labeled peptide was identified as residues 174-199. Sequencing of this peptide identified Tyr-181 and Tyr-188 as labeled residues.

Identification of a putative cellular receptor for the lentivirus visna virus

One mechanism by which viral tropism may be controlled is by the expression of a specific virus receptor on the cell surface. This paper reports the identification of a putative cellular receptor for visna virus, the prototype virus of the family Lentiviridae. Using a virus overlay protein blot assay we identified a group of polypeptides of apparent Mr 30K to 33K which interacts with visna virus and is present on permissive but not non-permissive cells. A rat polyclonal anti-ovine major histocompatibility complex (MHC) class II antigen (Ag) serum raised to immunopurified MHC class II Ag, but not preimmune serum, blocked the interaction of visna virus with these polypeptides. In an ELISA, immunopurified MHC class II Ag bound to visna virus but not to bovine parainfluenza 3 virus. Preincubation of visna virus with immunopurified soluble MHC class II Ag resulted in a marked decrease in virus-induced syncytium formation, i.e. preincubation with class II Ag inhibited infection with visna virus, but we have been unable to inhibit infection using class II Ag-specific antisera. These results suggest that ovine MHC class II Ag acts as a component of a cellular receptor for visna virus. This is of particular interest owing to the close similarities between visna virus and human immunodeficiency virus (HIV), and the relationship between MHC class II and CD4, the cellular receptor for HIV. It is also of relevance to recent reports that a growing number of viruses utilize polypeptides of the Ig supergene family as receptors.

Retroviral arthritis: phenotypic analysis of cells in the synovial fluid of sheep with inflammatory synovitis associated with visna virus infection

A phenotypic analysis on synovial fluid cells from the carpal and tarsal joints of sheep with visna virus-induced inflammatory synovitis was performed. The results showed increased representation of cells bearing lymphocyte, macrophage, and dendritic cell markers compared to equivalent synovial fluid cells from normal uninfected age-matched controls. In infected sheep, CD8+ T cells tended to predominate over CD4+ cells, while the numbers of gamma delta T cells varied from being absent in some samples to constituting the major T cell subset in others. B cells were found in relatively smaller numbers. Analysis of the large mononuclear cells showed that they stained with monoclonal antibodies that recognize macrophages and afferent lymph dendritic cells. Major histocompatibility complex (MHC) class II+ macrophage/dendritic cells were found in normal joints, but significantly elevated proportions of such cells were present in the carpal joints of infected sheep. The intensity of MHC class II staining was also significantly elevated in infected animals compared to control animals. A high proportion of these cells also stained for CD1 in both normal and infected animals, but were significantly elevated in number in the carpal joints of infected sheep. The elevated proportion of cells expressing molecules associated with accessary cell function and the increase in the numbers of accessory molecules per cell suggests an enhanced capacity for presenting antigen to a variety of T cell subsets within the joints of infected sheep, which could initiate or perpetuate potentially damaging local synovial inflammatory responses.

Use of DNA fingerprinting in paternity analysis of closely-related Exmoor ponies

DNA fingerprinting techniques were used to try to resolve the parentage of an Exmoor pony foal. Three young Exmoor ponies, one female and two males, shared a paddock and the female subsequently became pregnant. The two possible sires were three-quarter siblings and were also half-siblings to the dam. Southern hybridisation of Exmoor pony DNA with human mini-satellite probes resolved the disputed parentage in spite of the fact that there was a 70 per cent band share between the individuals involved. Colt M6 was 2.06 times more likely to be the father than an uncle, and Colt M3 was 477 times more likely to be an uncle than the father.

Variation of the amide I and amide II peak absorbance ratio in human hair as measured by Fourier transform infrared spectroscopy

Human scalp hair samples were examined by Fourier transform infrared spectroscopy and the ratio of the amide I to amide II band absorbances was determined. The effects of hair oxidation, color, age of sample, and sex of source were examined. Scalp hair from 98 individuals was also analyzed. While there were differences in the amide absorption band ratios, these were difficult to relate to the individualization of the hair samples and did not appear to have a sufficient discriminatory value for routine forensic use.

Immunohistology of lymph nodes draining local skin reactions (chancres) in sheep infected with Trypanosoma congolense

Marked enlargement of lymph nodes draining local skin reactions (chancres) occurred in sheep following intradermal inoculation of cultured metacyclic forms of Trypanosoma congolense. Histologically, these lymph nodes were characterized by follicular hypertrophy and hyperplasia, compression and relative reduction of the paracortical areas and expansion of the medullary regions. Immunohistochemical staining with monoclonal antibodies to ovine lymphocyte subsets and Fc receptor (FcR) bearing macrophages, revealed increased expression of B cells (CD45R+), major histocompatibility complex (MHC) Class II, FcR+ macrophages, and CD1+ cells in the cortical and paracortical areas. The paracortical areas were found to be sparsely populated by CD5+, CD4+ and CD8+ cells, while the medullary areas contained numerous CD8+ cells and FcR+ macrophages. FcR+ macrophages were also present in cortical trabecular and subcapsular sinuses. As the chancre regressed, lymph node reactivity also subsided and fewer B cell follicles were observed and there was decreased expression of CD45R+ and MHC Class II+ cells.

Analysis of the CD1 cluster in sheep

The anti-CD1 monoclonal antibodies submitted to the 1st International Workshop on Leucocyte Differentiation Antigens of Cattle, Sheep and Goats were tested for their reactivity on sheep skin, thymus and lymph node and for their reactivity with sheep efferent and afferent lymph and peripheral blood. With the exception of 20-27 they all stained that same cell populations. The antibodies precipitated molecules with a heavy chain of 46,000 apparent molecular weight and a light chain of 14,000 apparent molecular weight. VPM5 and CC14 antigens were purified by affinity chromatography. All the antibodies cross-reacted with these molecules. The results show that 20-27 recognises the same molecules as the other antibodies and suggest that 20-27 is a pan CD1 monoclonal antibody and the other monoclonal antibodies are homologues of the human CD1b molecules.

Detection of border disease virus in sheep efferent lymphocytes by immunocytochemical and in situ hybridisation techniques

The prefemoral efferent lymphatics of four sheep persistently infected with a non cytopathic (NCP) isolate of border disease virus (BDV) were cannulated. Recovered lymphocytes were examined for the presence of virus by an immunocytochemical technique employing a pool of monoclonal antibodies which recognise the 120K non-structural polypeptide of NCP BDV. The results revealed that 9.5% of the lymphocytes carried virus antigen. Lymphocytes from two of the sheep were studied by in situ hybridisation using a viral antisense RNA probe complementary to the region of the BDV genome coding for the 120K polypeptide. This showed that 70-80% of the cells were infected, confirming the greater sensitivity of the in situ hybridisation technique.

Cellular phenotypes in Trypanosoma congolense infected sheep: the local skin reaction

Mononuclear cell subpopulations in local skin reactions (chancres) in sheep infected with metacyclic forms of Trypanosoma congolense were studied by indirect immunoperoxidase staining using a panel of monoclonal antibodies (MoAbs) specific for ovine leucocyte subsets. Morphometric analysis revealed significant increases in numbers of cells expressing CD5, CD4, CD8, CD45R (mainly B cells), major histocompatibility complex (MHC) class II antigens, Fc receptors (FcR) on macrophages (VPM32) and FcR on B cells and macrophages (VPM33) from five days post-infection. B cells which also expressed MHC class II were found mainly in dense aggregates. The CD4/CD8 ratios were raised over pre-infection levels at 5-7 days post-infection. In sheep which had been infected, treated with trypanocidal drugs and then challenged with an heterologous serodeme of T. congolense, changes in cellular phenotype kinetics were similar to those seen in the skin in primary infections. Sheep superinfected with either an homologous or an heterologous, T. congolense serodeme showed only mild cellular infiltration and slight increases in various cellular phenotypes at the sites of inoculation.

Uptake of antigen by afferent lymph dendritic cells mediated by antibody

Dendritic cells isolated from sheep afferent lymph were examined for their ability to bind soluble protein and peptide antigens labeled with fluorescein both in in vitro assays and following intradermal injection of antigen in vivo. Analysis of dendritic cells by flow cytometry revealed weak direct binding of proteins and peptide antigens. However, the degree of uptake was greatly enhanced in the presence of specific antibody in vitro or if antigen was injected intradermally into antigen-primed sheep. About 60% of dendritic cells possessed the ability to take up antigen in both the in vitro and in vivo experiments. The uptake of antigen occurred very rapidly, reaching maximum values in terms of cell numbers and fluorescence intensity in less than 5 min in vitro and 20-40 min following in vivo challenge. Both sheep IgG subclasses could mediate this effect, but F(ab')2 fragments were ineffective. Procedures adopted to remove complement components from the in vitro test mixtures did not result in any reduction in the binding of antigen by dendritic cells. Two-color flow cytometry analysis of the dendritic cell population further showed that 43% of cells taking up the antigen/antibody complexes were CD1+, suggesting a relationship between these cells and Langerhans' cells or other dendritic cells in skin. The results, thus, indicate that approximately two thirds of sheep afferent lymph dendritic cells bind antigen/antibody complexes via an Fc receptor, a mechanism which could be important in the accentuated accessory function of these cells known to occur following secondary antigen challenge.

Characterization of monoclonal antibodies specific for alpha- and beta-chains of sheep MHC class II

In order to identify and characterize the sheep major histocompatibility complex (MHC) class II molecules, a panel of 19 monoclonal antibodies (mAb) has been raised following immunization of mice with a variety of class II antigen preparations. Antibodies were selected by ELISA using immunopurified sheep class II as antigen and further screened for the ability to react on immunoblots. Nine mAb reacted with the beta-chain and four reacted with the alpha-chain. The chain specificity of the remainder could not be determined as they did not blot. The anti-alpha and anti-beta mAb all reacted with deglycosylated class II. With the exception of one anti-alpha and one anti-beta antibody, the antibodies reacted with both efferent lymph cells and peripheral blood mononuclear cells (PBMC). Three of the anti-sheep class II mAb reacted with human PBMC.

Monoclonal antibodies to the sheep analogues of human CD45 (leucocyte common antigen), MHC class I and CD5. Differential expression after lymphocyte activation in vivo

This paper describes three anti-sheep monoclonal antibodies. The tissue distribution and apparent molecular weight of the antigens detected by these antibodies is consistent with them reacting with sheep leucocyte common antigen (CD45 (VPM18], MHC class I (VPM19) and CD5 (VPM29). An ELISA method is described that permits the cross-reactivity of different antibodies to be assessed, this confirms the identity of the antigens detected by VPM18, VPM19 and VPM29. This method is also of value as either a positive or a negative screen in the construction of further monoclonals. A study of the expression of these three antigens on efferent lymph small lymphocytes and antigen-activated lymphoblasts shows that the density of CD45 on lymphoblasts (activated either in vivo or in vitro) is approximately half that of small lymphocytes whereas the density of MHC class I is the same in both populations. Furthermore, about 75% of small lymphocytes express CD5 but less than 10% of lymphoblasts are positive. Cell membrane CD5 expression is lost on lymphocyte activation. It does not seem to be linked to cell membranes via phosphatidylinositol and the loss is not due to the breaking of that link.

Stability of metacyclic variable antigen types (M-VATs) during the early stages of infection with Trypanosoma congolense

Expression of nine metacyclic variable antigen types (M-VATs) of Trypanosoma congolense in chancres from infected rabbits was determined using monoclonal antibodies raised against metacyclic forms of trypanosomes. Trypanosomes present in chancres 7-9 days post infection expressed M-VATs present in metacyclic populations of the parasites. The majority of M-VATs expressed showed little proportional change from those observed on metacyclic trypanosomes during this period although expression of one M-VAT increased, and another decreased. Although trypanosomes in chancres continued to express M-VATs, other VATs, not present in the M-VAT repertoire were also expressed and neutralization tests showed that new VATs appeared by 7 days after infection. In infected sheep neutralizing antibodies against M-VATs were detected by day 14 in lymph from efferent lymphatics draining lymph nodes in the region of chancres. Neutralizing antibodies directed against metacyclics were also present in the serum by day 14 and were still detectable for up to 35 days post infection. Hence, it is likely that in the vertebrate host the trypanosomes multiplying in the skin at the site of tsetse bit express all M-VATs characteristic of that particular serodeme, enabling the host to develop immunity to all antigen types present in the M-VAT repertoire.

Afferent lymph dendritic cells: a model for antigen capture and presentation in vivo

We review the phenotypic and functional properties of sheep afferent lymph dendritic cells. These dendritic cells bear surface immunoglobulin and can acquire antigen/antibody complexes, both in vitro and in vivo. Our data suggest a role for Fc receptors in the capture of antigen by these cells. Dendritic cells collected after in vivo antigen pulsing are capable of stimulating T cell proliferation in an antigen-specific manner. Afferent dendritic cells express all the known groups of presentational molecules involved in activation of T cells, namely MHC class I and class II, and CD1. These results suggest a role for afferent dendritic cells in the activation of alpha beta and gamma delta T cells.

IL-2-like activity in lymph fluid following in vivo antigen challenge

The majority of studies that characterize lymphokines utilize in vitro activation of lymphocytes. In an attempt to identify and characterize lymphokines released from tissue sites, we have cannulated sheep lymphatic vessels and collected lymph that drains a site of in vivo antigen challenge. Lymph draining directly from a site of intradermal antigen challenge (afferent lymph) and lymph draining an antigen-stimulated lymph node (efferent lymph) were assayed for lymphokine activity by the ability of cell-free lymph fluid to stimulate the proliferation of sheep Con A-blasts. Afferent and efferent lymph, both collected at 24 and 48 hr following in vivo antigen challenge, with either ovalbumin or PPD in primed animals, stimulates the proliferation of sheep Con A-blast cells. This in vivo-derived lymphokine activity and in vitro-generated sheep Con A supernatant has an active component with properties similar to interleukin-2 (IL-2) that has been described in several other species. The IL-2-like material is precipitated by 40-80% ammonium sulphate saturation, has a molecular weight (MW) of 20,000 MW as judged by gel filtration chromatography, and is eluted from an anion-exchange HPLC column with 125 mM NaCl. HPLC ion-exchange fractionation of the 20,000 MW material from lymph fluid shows differences between afferent and efferent lymph material. The fractionation of afferent material is similar to that of in vitro generated Con A supernatant material with a single peak of activity eluted by 125 mM NaCl. In contrast, the 20,000 MW material from efferent lymph elutes with peaks of activity at 125 and 300 mM NaCl.

Postpartum depression and postpartum adaptation: overlapping constructs?

In order to examine the course of normal postpartum adjustment compared to the symptomatology of postpartum depression, 25 postpartum women who met Research Diagnostic Criteria for either major or minor depression were compared to 24 non-depressed postpartum women. The Schedule for Affective Disorders and Schizophrenia (SADS) and the Beck Depression Inventory (BDI) were administered to all subjects. Results suggest that sleep disturbances and loss of sexual interest are common concomitants of normal postpartum adjustment. A discriminant function analysis indicated that the cognitive-affective symptoms of loss of energy, guilt, difficulties in concentration, and loss of interest in usual activities discriminated between depressed and non-depressed women most efficiently. Finally, there was a lack of concordance between the BDI and the SADS interviews, which suggests that the BDI may not be an appropriate instrument for diagnosing depression in a postpartum sample.