bluuebunny/crossref_metadata_2025 huggingface dataset:
Tomato dwarf leaf curl virus, a new bipartite geminivirus associated with tomatoes and peppers in Jamaica and mixed infection with tomato yellow leaf curl virus
Authors: Roye  , Wernecke  , McLaughlin  , Nakhla  , Maxwell
Published: March 2003

Genomic characterization using nonradioactive probes, polymerase chain reaction with degenerate primers for whitefly transmitted geminiviruses and nucleotide sequencing were used to describe a new bipartite geminivirus, associated with dwarfing and leaf curling of tomatoes and peppers in Jamaica. Partial DNA‐A and DNA‐B clones were obtained. DNA sequence analysis showed that tomato and pepper samples have a similar geminivirus associated with them. Nucleotide sequence identity > 92% between the common regions of DNA‐A and DNA‐B confirmed the bipartite nature of the Jamaican geminivirus isolates. Nucleotide sequence comparisons of DNA‐A and DNA‐B with those of geminiviruses representing the major phylogenetic groups of Western Hemisphere geminiviruses showed the greatest similarity to potato yellow mosaic virus and members of the Abutilon mosaic virus cluster of geminiviruses. This new virus is given the name tomato dwarf leaf curl virus (TDLCV) because of the dwarfing and leaf curling symptoms associated with infected tomato plants. Polymerase chain reaction and Southern hybridization showed mixed infections of TDLCV with tomato yellow leaf curl virus from Israel in 16% of the field samples of tomatoes and peppers.
Characterization of a potyvirus from eggplant (Solanum melongena) as a strain of potato virus Y by N‐terminal serology and sequence relationships
Authors: Bhat  , Varma  , Pappu  , Rajamannar  , Jain  , Praveen
Published: March 2003

A potyvirus (eggplant mottle virus, EMoV) causing mosaic mottling in eggplant (Solanum melongena) was characterized on the basis of biological, serological and partial nucleotide sequence properties. EMoV infected Chenopodium amaranticolor and members of the Solanaceae. Polyclonal antiserum against EMoV showed antigenic relationship with henbane mosaic potyvirus (HMV) and potato Y potyvirus (PVY). Virus‐specific antibodies directed to the N‐terminal region of EMoV cross‐reacted only with PVY. Determination and comparison of nucleotide sequence of the coat protein (CP) and the 3′‐untranslated region (UTR) of EMoV with other potyviruses showed that the level of homology was highest with PVY isolates. Comparative sequence analyses of the CP amino acid and 3′‐UTR sequences with distinct PVY isolates placed EMoV within the PVYO subgroup.
Improved detection of citrus psorosis virus using polyclonal and monoclonal antibodies
Authors: Alioto  , Gangemi  , Deaglio  , Sposato  , Noris  , Luisoni  , Milne
Published: March 2003

Citrus psorosis is a serious and widespread disease associated with citrus psorosis virus (CPsV), a novel filamentous negative‐stranded virus in the genus Ophiovirus. Laborious and costly indexing on test plants has been the only routine diagnostic method available, but recently an antiserum usable in double antibody sandwich (DAS) ELISA has been prepared. Here, major improvements to the DAS‐ELISA protocol, a new purification method, and production of two monoclonal antibodies (mabs) to CPsV, an IgG and an IgM are reported. A highly sensitive triple antibody sandwich (TAS) ELISA making use of the mabs is described. In glasshouse citrus the homologous virus was still detectable at a tissue dilution of 1/6250 in DAS and at 1/31250 in TAS‐ELISA. Both the DAS and IgG mab‐TAS formats detected all CPsV isolates so far tested (from Argentina, Italy, Lebanon, Spain and the USA). A few isolates were not detected by the IgM mab.
Variation in populations of Phytophthora infestans in Finland and Norway: mating type, metalaxyl resistance and virulence phenotype
Authors: Hermansen  , Hannukkala  , Hafskjold Nærstad  , Brurberg
Published: March 2003

Phytophthora infestans was isolated from potato leaves and tubers collected from different parts of Finland in 1990–96 and Norway in 1993–96. Isolates were assessed for mating type, resistance to metalaxyl and virulence phenotype. In Finland 15% of 200 isolates tested and in Norway 25% of 642 tested were A2 mating type. Differences in the A1/A2 ratio were evident among regions and A2 was not found in northern areas. In Finland the frequency of metalaxyl‐resistant isolates, among 1834 tested, decreased from 59% in 1990–95 to 2% in 1996. In Norway 59% of 491 isolates tested were resistant to metalaxyl in 1996. Among 269 Finnish and 105 Norwegian isolates, all known virulence genes were found in both countries and race 1.3.4.7.10.11 was the most common (resistance gene R9 was not included in the differential set). Oospores were observed in potato leaves from three locations in the southern part of Norway. The implications of the ‘new’ populations in the Nordic countries are discussed.
A sensitive method for detecting bamboo mosaic virus (BaMV) and establishment of BaMV‐free meristem‐tip cultures
Authors: Hsu  , Annamalai  , Lin  , Chen  , Chang  , Lin
Published: March 2003

A sensitive method was used to detect bamboo mosaic virus (BaMV) and its associated satellite RNA (satBaMV) by 32P‐ and digoxigenin (Dig)‐labelled probes synthesized from cDNA clones of BaMV genomic (L probe) and satBaMV (S probe) RNA. Both the 32P‐ and Dig‐labelled L and S probes could detect as little as 490 pg of BaMV viral RNA by slot‐ and dot‐blot hybridization. In infected leaf extracts, 32P‐labelled L and S probes detected virus at 25‐fold higher dilutions than Dig‐labelled probes, which were also successfully used to detect BaMV infection in plants derived from meristem‐tip culture. However, immunoassays failed to detect BaMV in meristem culture. By dot‐blot hybridization assays, 25% of the seedlings were shown to be virus‐free. These results suggest that a highly sensitive method for the detection of BaMV infection is required for the establishment of BaMV‐free cultures. Meristem‐tip culture also provides an efficient method for obtaining virus‐free bamboo plants.
Disease complex in coffee involving Meloidogyne arabicida and Fusarium oxysporum
Authors: Bertrand B. , Nuñez C. , Sarah J.‐L.
Published: March 2003

Coffee corky‐root disease, also called corchosis, was first detected in 1974 in a small area of Costa Rica where the root‐knot nematode Meloidogyne arabicida is the dominant species. An epidemiological study revealed a constant association between Meloidogyne spp. and Fusarium sp. in cases of corky root. No corky root appears to have been reported in association with Meloidogyne exigua, which is the prevalent root‐knot nematode on coffee in Costa Rica. Fusarium spp. are often cited as components of disease complexes in association with nematodes. Combined inoculations using M. arabicida or M. exigua with Fusarium oxysporum under controlled conditions showed that only the combination with M. arabicida produced corky‐root symptoms on Coffea arabica cvs Caturra or Catuai. Fusarium oxysporum alone was nonpathogenic. Meloidogyne exigua or M. arabicida alone caused galls and reduction in shoot height, but no corky‐root symptoms. When cultivars susceptible and resistant to M. arabicida were studied under field conditions for 5 years, all the susceptible cultivars exhibited corky‐root symptoms on 40–80% of their root systems. Cultivars that were resistant to M. arabicida but not to M. exigua showed no corky root. These observations lead to the conclusion that corky‐root disease has a complex etiology, and emphasize the dominant role of M. arabicida as a predisposing agent to subsequent invasion by F. oxysporum. Consequently, genetic resistance to M. arabicida appears to provide an effective strategy against the disease.
Reduction of postharvest losses of Galia melon by a short hot‐water rinse
Authors: Fallik E. , Aharoni Y. , Copel A. , Rodov V. , Tuvia‐Alkalai S. , Horev B. , Yekutieli O. , Wiseblum A. , Regev R.
Published: March 2003

A rapid method for simultaneously rinsing and disinfecting fresh harvested produce using a hot‐water rinse and brushes (HWRB) was tested on Galia melon (Cucumis melo cv. reticulatus) fruit. The optimal treatment to reduce decay while maintaining fruit quality after prolonged storage and marketing simulation was 59 ± 1°C for 15 s. Trial shipments by sea transport to Europe demonstrated that treating melon with a commercial‐scale HWRB machine (3 tonnes fruit h−1) maintained significantly better overall quality of treated fruit compared with untreated fruit.
Exposing spores of Alternaria alternata and Fusarium solani to 60°C for about 15 s in vitro reduced germination by 48% and 42%, respectively. Employing HWRB resulted in a 3‐log reduction in total colony‐forming units (CFU) of the epiphytic microbial population, compared with untreated fruit. Scanning electron microscopy (SEM) showed that HWRB removed soil, dust and fungal spores from the fruit surface, and partially or entirely sealed natural openings in the epidermis.
An efficient baiting assay for quantification of Phytophthora cinnamomi in soil
Authors: Eden M. A. , Hill R. A. , Galpoththage M.
Published: March 2003

A quantitative baiting assay system for Phytophthora cinnamomi with greater sensitivity than the orthodox serial dilution end‐point method was developed. A system of efficiently handling large numbers of subsamples using racks of tubes is described, and the factors determining baiting efficiency with blue lupin (Lupinus angustifolius) radicles were studied. Significantly greater baiting efficiency was obtained when the subsample size was decreased. The optimum temperature was found to be ≈ 25°C for baiting and 20–25°C for bait incubation. Air‐drying of soil for two days killed P. cinnamomi propagules. Escape of zoospores from test soil was reduced by the presence of overlying material. Reduction was greatest when the overlying material was of fine particle size and of greater depth. This confirmed the need in assay work to keep soil subsample size small and avoid destruction of the soil structure in preparation. The peak of zoospore release from naturally infested soil occurred on the first day. Infection on radicles decreased as a function of distance from radicle tip.
Variation in Fusarium graminearum isolates from Nepal associated with their host of origin
Authors: Carter J. P. , Rezanoor H. N. , Desjardins A. E. , Nicholson P.
Published: March 2003

A collection of group II Fusarium graminearum isolates obtained from maize, wheat and rice from different locations in Nepal were identified using a combination of morphological and molecular criteria. The variation within this collection was analysed using RAPD markers, intergenic spacer (IGS) RFLP and PCR polymorphisms. The isolates were divided into two groups, A and B, by RAPD analysis. Isolates in group A yielded four different PCR polymorphic markers, but all the isolates in group B yielded a single polymorphic marker. The IGS RFLP analysis was consistent with division of the isolates into two groups. Isolates from wheat and rice were more frequently placed in group A, with isolates from maize more evenly distributed between the groups. Results indicate that host preference might be a factor in the division of isolates, although the year of isolation may also have had an influence. No geographical factors or agricultural practices could be identified to account for the observed variation.
Genetic relationships and isozyme variability in the Heterodera avenae complex determined by isoelectrofocusing
Authors: Andrés M. F. , Romero M. D. , Montes M. J. , Delibes A.
Published: March 2003

Isozyme variability was assessed among the principal species of the cereal cyst nematode complex to complete and enhance the information provided by classical nematode systematics, in order to clarify inter‐ and intraspecific relationships within this complex. Twenty populations of cereal cyst nematodes (Heterodera avenae, H. filipjevi, H. latipons and H. mani) were compared by means of five different isoenzymatic systems (esterase, malate dehydrogenase, phosphoglucoisomerase, phosphoglucomutase and superoxide dismutase) using isoelectrofocusing (IEF) on the electrophoretic separation. The results are in agreement with previous morphological and biochemical characterizations, which established genetic diversity between the Gotland strain and H. avenae and identified the Gotland strain with H. filipjevi. Populations from Israel, all included in the H. avenae group, exhibited well‐defined intraspecific dissimilarity. The highest degree of polymorphism was found in the H. avenae group for all five enzymatic systems studied. The H. mani population was also included in the H. avenae group by these isozyme analyses. Malate dehydrogenase, phosphoglucoisomerase and phosphoglucomutase isozymes, fractionated for the first time by IEF in the cereal cyst nematode complex, displayed a higher level of polymorphism than using conventional electrophoresis. Isoelectric focusing has proved to be a useful tool for detecting genetic diversity within and among species of the cereal cyst nematode complex and for taxonomic purposes.
Elimination of Sugarcane yellow leaf virus from infected sugarcane plants by meristem tip culture visualized by tissue blot immunoassay
Authors: Fitch M. M. M. , Lehrer A. T. , Komor E. , Moore P. H.
Published: March 2003

Sugarcane yellow leaf virus (SCYLV), a member of the Luteoviridae, is implicated in the sugarcane disease known as yellow leaf syndrome (YLS), which is characterized by yellowing of the leaf midrib followed by leaf necrosis and possible growth suppression. YLS is distributed worldwide and susceptible cultivars are commonly infected with SCYLV. However, not all cultivars infected with SCYLV show symptoms of YLS and some cultivars that show symptoms do so sporadically. Since it is difficult to obtain virus‐free plants of susceptible cultivars, it has not been possible to study the factors involved in SCYLV infection nor the effects of infection on plant growth and yield. A tissue blot immunoassay was used to visualize in vivo presence of the virus so that virus‐infected and virus‐free plants could be distinguished. Meristem tip cultures were used to produce virus‐free plantings of six SCYLV‐susceptible sugarcane cultivars. Nearly all of the regenerated sugarcane lines remained virus‐free over a period of up to 4 years, whether grown in isolated fields or in the glasshouse. Experimental re‐infection of the virus‐free plants by viruliferous aphids demonstrated that meristem tip culture did not affect susceptibility of sugarcane to SCYLV. Improved diagnosis and production of virus‐free plants of SCYLV‐susceptible cultivars will facilitate research to quantify the effect of the virus on yield and to analyse the processes involved in disease development.
Differential induction of superoxide dismutase in downy mildew‐resistant and ‐susceptible genotypes of pearl millet
Authors: Babitha M. P. , Bhat S. G. , Prakash H. S. , Shetty H. S.
Published: March 2003

Differential induction of superoxide dismutase (SOD) in downy mildew‐resistant and ‐susceptible genotypes of pearl millet (Pennisetum glaucum) was observed on inoculation with Sclerospora graminicola. SOD activity was studied in resistant (IP18292) and susceptible (23B) pearl millet seedlings inoculated with S. graminicola. SOD activity increased by 2·3‐fold in resistant seedlings upon inoculation. SOD activity was greatest in roots, with a specific activity of 3182 U per mg protein, after inoculation. SOD activity increased in all the resistant genotypes upon inoculation with S. graminicola. Native PAGE analysis showed four isozymes of SOD, three of which (SOD‐1, ‐2 and ‐4) were Cu/Zn‐SOD, whereas isozyme SOD‐3 was Mn‐SOD. This study also revealed increased intensity of all four isozymes of SOD in the resistant genotype upon inoculation. The involvement of SOD in pearl millet (host)–downy mildew pathogen interaction is discussed.
Phomopsis alnea, the cause of dieback of black alder in Italy
Authors: Moricca S.
Published: March 2003

Black alder (Alnus glutinosa) occurs naturally on moist soils and along streams and rivers throughout most of its range. Groves of this species in north‐central Italy were recently found to be attacked by the mitosporic coelomycete Phomopsis alnea, which causes perennial stem cankers and dieback. The fungi Melanconium apiocarpium and a Hymenopsis sp. were also frequently found on necrotic alder tissue, occasionally invading the living bark. All these fungi were tested for pathogenicity in two seasonal inoculation trials on seedlings of black alder, Italian alder (Alnus cordata) and green alder (Alnus viridis) that were either normally watered or water‐stressed. Phomopsis alnea actively colonized the seedlings and reproduced the symptoms observed in the field. The other fungi behaved as weak parasites, only occasionally spreading to apparently healthy bark tissue. It appears that these fungi are saprobes, commonly colonizing bark and twigs already killed by P. alnea. Symptoms caused by P. alnea in the field were exacerbated on dry sites and by seasonal drought stress. On artificially inoculated and water‐stressed seedlings, both the incidence and severity of P. alnea also increased, causing extensive mortality. The data provide evidence for the belief that P. alnea becomes a factor in the dieback of natural black alder woodlands when trees are first impaired by wounding agents and then subjected to unusual extended drought.
Localization of the Brain Lesion Affects the Lateralization of T‐Lymphocyte Dependent Cutaneous Inflammation. Evidence for an Immunoregulatory Role of the Right Frontal Cortex–Putamen Region
Authors: Tarkowski  , Jensen  , Ekholm  , Ekelund  , Blomstrand  , Tarkowski
Published: March 2003

We have previously demonstrated that brain lesions caused by stroke led to the lateralization of T‐cell dependent inflammation. The purpose of this study was to assess the impact of localization of the brain lesion on lateralization of immune responsiveness. The delayed‐type hypersensitivity (DTH) reaction was used as an in vivo measure of antigen specific T‐lymphocyte reactivity. All stroke patients were examined with computed scan tomography (CT) of the brain to ascertain the localization and extent of the brain lesion. Patients with right‐sided brain lesions displayed significantly larger (P = 0.008) DTH responses on the paretic side compared to the contralateral side. Detailed analysis of the localization of the brain lesion revealed that infarcts encompassing frontal lobe–putamen led to significantly larger (P = 0.007) DTH responses on the paretic side compared to the contralateral side. Localization of the brain lesion affects the lateralization of DTH, supporting an asymmetrical modulation of the immune response. In addition, our study points to the frontal cortex–putamen as a putative brain centre regulating the magnitude of immune responses.
Immunomodulation Induced by Ascaris suum Extract in Mice: Effect of Anti‐Interleukin‐4 and Anti‐Interleukin‐10 Antibodies
Authors: Macedo  , Faquim‐Mauro  , Ferreira  , Abrahamsohn
Published: March 2003

Simultaneous immunization of mice with an Ascaris suum extract (Asc) and ovalbumin (OA) markedly affects the immune response to OA. The role of interleukin (IL)‐4 and IL‐10 induced by Asc immunization on the modulation of antigen‐specific and mitogen‐induced responses was investigated following single or combined cytokine‐specific monoclonal antibody (MoAb) treatment of mice before immunization with OA + Asc. Immediate hypersensitivity reactions to aggregated OA and OA‐specific immunoglobulin (Ig)G2a antibody production were completely restored only when both IL‐4 and IL‐10 were neutralized. These findings were associated with enhanced interferon (IFN)‐γ secretion by OA‐stimulated lymph node (LN) cells. In addition, the Asc‐specific cytokine response in anti‐IL‐4 plus anti‐IL‐10 MoAb treated mice was shifted towards a Th1 phenotype, with an increase in IFN‐γ and IL‐2 levels and a decrease in IL‐4, but not in IL‐10, levels. Consequently, Asc‐specific IgG2a antibody production increased, whereas IgE titres diminished in these animals. These results indicate that IL‐4 and IL‐10 act together in the Asc‐induced mechanism of antigen‐specific pansuppression. In contrast, modulation of Concanavalin A (Con A)‐induced cytokine responses in Asc‐immunized mice appears to be essentially mediated by an IL‐4‐dependent mechanism, since the neutralization of just IL‐4 (and not of IL‐10), either in vivo or in vitro, changed the cytokine profile from a Th2 towards a Th1 type. However, OA and Asc‐specific cell responses were not modified by either anti‐IL‐4 or by anti‐IL‐4 + anti‐IL‐10 MoAbs in vitro treatments, suggesting that the induction of a Th2 response to Asc components concomitant to OA immunization has a strong suppressive effect on the priming stage of OA‐specific Th1 type response.
A Novel Antibody Directed Against a Three‐Dimensional Configuration of a 95‐kDa Protein in Patients with Autoimmune Hepatic Diseases
Authors: Miyachi  , Matsushima  , Hankins  , Hirakata  , Mimori  , Hosaka  , Amagasaki  , Miyakawa  , Kako  , Shibata  , Onozuka  , Ueno
Published: March 2003

Sera from patients with primary biliary cirrhosis recognize various cellular components, such as mitochondria, centromere, nuclear envelope, and multiple nuclear dot antigens. There also appears to be a novel antibody reacting with a particular protein in these sera. The presence of this antibody was investigated by double immunodiffusion using rat liver cytoplasmic antigens, by immunoprecipitation of [35S]‐methionine labelled HeLa cell extracts, and by immunoblot using disrupted HeLa cell extracts. Test sera were obtained from 491 patients with various liver diseases. Nine of the 491 sera were found to react with a 95‐kDa protein as determined by immunoprecipitation of [35S]‐methionine labelled HeLa cell extracts and by double immunodiffusion using a rat liver microsomal preparation. However, these same nine sera showed no reaction in the immunoblot assay. On the basis of its molecular mass and its presence in the cytoplasmic fraction, this antigen was named p95 C. This anti‐p95 C antibody was detected in six of 50 (12%) sera from patients with primary biliary cirrhosis, and in three of 31 (9.7%) sera from patients with autoimmune hepatitis, but not in any of the remaining 410 sera obtained from patients with other hepatic diseases. It is concluded that anti‐p95 C antibody reacts primarily with the native form of the 95‐kDa protein, and represents another possible analyte for diagnosing autoimmune liver diseases.
Decreased Expression of Signal‐Transducing CD3 ζ Chains in T Cells from the Joints and Peripheral Blood of Rheumatoid Arthritis Patients
Authors: Matsuda  , Ulfgren  , Lenkei  , Petersson  , Ochoa  , Lindblad  , Andersson  , Klareskog  , Kiessling
Published: March 2003

Although T cells from patients with rheumatoid arthritis (RA) have previously been determined to have poor proliferative responses to a variety of stimuli, the underlying mechanism is not known. We have investigated the expression of the signal‐transducing ζ molecule in subsets of T cells and natural killer (NK) cells derived from the peripheral blood mononuclear cells (PBMC) and synovial fluid mononuclear cells (SFMC) of RA patients using quantitative flow cytometry, Western blot analysis and immunohistochemistry. A decrease of ζ expression was apparent in all investigated lymphocyte subsets from the PBMC and SFMC of RA patients, as compared to the corresponding subsets from healthy age‐ and sex‐matched controls. A less pronounced reduction of cell surface‐located CD3 ε, CD4 and CD8 was also located in T cells from SFMC as compared to PBMC from RA patients. Biochemical demonstration of the low or absent CD3 ζ in PBMC from patients with RA was achieved by Western blot analysis. Immunohistochemical staining and image analysis also confirmed the low expression of ζ chains in synovial tissue of RA patients. The possibility that the decreased expression of ζ and of immune functions of T cells from RA patients may be related to the presence of free oxygen radiclals, as we have previously reported in cancer patients, should be considered.
Early T‐Cell Apoptosis and Fas Expression During Antiretroviral Therapy in Individuals Infected with Human Immunodeficiency Virus‐1
Authors: Aries  , Weyrich  , Schaaf  , Hansen  , Dennin  , Dalhoff
Published: March 2003

Several lines of evidence suggest that Fas‐mediated apoptosis is involved in the CD4 T‐cell depletion in human immunodeficiency virus‐1 (HIV‐1) infection. To investigate this, we studied changes in peripheral blood, early T‐cell apoptosis and Fas expression after initiation of antiretroviral therapy (ART) in 18 HIV‐1‐infected individuals. Flow cytometric analysis was performed with ApostainTM and CD4, CD8 and Fas staining. Fas expression was quantified by standardized beads. The levels of CD4 and CD8 T cells with early apoptosis were increased comparably in HIV‐1‐infected individuals. Despite elevated CD4 T cell counts, no decline in early T‐cell apoptosis could be detected during the first 8 weeks of ART. However, after 26 weeks of ART in five patients that showed a sustained reduction of viral replication there was a marked decrease in T cells with features of early apoptosis. No difference was found for Fas expression on early apoptotic T cells. Fas expression on CD4 and CD8 T cells was reduced after initiation of ART; this was independent of the CD4 T‐cell trend and indicates that the immediate CD4 T‐cell expansion during ART is probably not the result of a decreased rate of early apoptosis among peripheral blood CD4 T cells. However, preliminary data imply a long‐term reduction of early T‐cell apoptosis and Fas expression in patients who show a sustained reduction of viral replication.
Recurrent Herpes Simplex Virus‐Induced Erythema Multiforme: Different HLA‐DQB1 Alleles Associate with Severe Mucous Membrane Versus Skin Attacks
Authors: Malo  , Kämpgen  , Wank
Published: March 2003

In some individuals a local herpetic lesion precipitates a generalized inflammation of the skin, designated as erythema multiforme (EM). We determined the frequencies of the immune response genes of the HLA system by molecular HLA class II typing in 46 patients with EM and in many of their family members. Allele frequencies were correlated with disease form and disease‐inducing factors. We found that specific complications of HSV infection occur preferentially in patients with certain HLA‐DQB1 alleles. In 21 of the 46 patients EM was induced by recurrent HSV infection. Thirteen of these patients showing only minor or no involvement of mucous membranes had the HLA allele DQB1*0302 (phenotype frequency 61.9% versus 18.8% in controls, p corr = 0.0008) and all three patients with major involvement of mucous membranes had the rare HLA allele DQB1*0402 (phenotype frequency in controls 6,4%, p corr = 0.017).
Production of Interleukin‐4, Interferon (IFN)‐γ and IFN‐α in Human Immunodeficiency Virus‐1 Infection: An Imbalance of Type 1 and Type 2 Cytokines may Reduce the Synthesis of IFN‐α
Authors: Hober  , Benyoucef  , Chehadeh  , Chieux  , De La Tribonniere  , Mouton  , Bocket  , Wattre
Published: March 2003

Interferon‐α (IFN‐α) is an important molecule in the antiviral response, but cells from HIV‐1‐infected individuals show a reduced ability to secrete IFN‐α. We investigated an association between an imbalance of type 1/type 2 cytokines and the production of IFN‐α in HIV‐1 infection. We used whole blood culture to study the cytokine production profile, interferon‐γ (IFN‐γ) and interleukin‐4 (IL‐4), in response to HIV‐1 antigens and to study the Sendai Virus and HSV‐1‐induced‐production of IFN‐α in seven HIV‐1‐infected patients. An impaired synthesis of IFN‐α was obtained in patients with a predominant IL‐4 production (IL‐4 > IFN‐γ), and we found a positive correlation between the ex vivo production of IFN‐α and the IFN‐γ/IL‐4 ratio but not with the HIV RNA copy number in plasma. We investigated the role of T‐cell‐derived cytokines in the in vitro production of IFN‐α by PBMC from eight healthy donors, activated with Sendai Virus or HSV‐1. Whereas type 2 cytokines (IL‐4, IL‐13) inhibited virus‐induced IFN‐α synthesis, on the contrary, type 1 cytokines (IL‐2, IFN‐γ) enhanced it. A disarray in the T‐cell‐derived cytokine response may play a role in the defect of IFN‐α production in HIV‐1‐infected individuals. Further investigations are needed to explore this hypothesis.
Non‐Responsiveness to Mercury‐Induced Autoimmunity in Resistant DBA/2 Mice is not Due to Immunosuppression or Biased Th1‐Type Response
Authors: HU  , MÖLLER  , ABEDI‐VALUGERDI
Published: March 2003

Mercury can induce systemic autoimmunity in susceptible mouse strains characterized by a T‐cell‐dependent polyclonal B‐cell activation, increased serum levels of IgG1 and IgE antibodies, production of autoantibodies, and the formation of immune complexes in the kidneys. However, certain resistant mouse strains do not show any of the autoimmune manifestations after mercury injection. Th1/Th2 dichotomy has been proposed to be responsible for resistance and susceptibility, respectively. Immunosuppression has also been suggested in resistant animals after mercury injection. To test whether immunosuppression or a biased Th1‐type response was induced by mercury in resistant DBA/2 mice, we injected DBA/2 mice with mercury for 1 or 3 weeks and then immunized the mice with horse red blood cells (HRBCs) to study whether the subsequent humoral response to HRBCs was inhibited or skewed to the production of antibodies of IgG2a isotype switched by Th1‐type cytokines. We found that there was no reduction of the number of splenic antibody‐producing cells in the subsequent response to HRBCs compared with saline‐treated mice. By haemagglutination tests, the titers of HRBC‐specific antibodies were the same after HRBCs injection in both mercury‐ and saline‐treated DBA/2 mice. There was no increase in total serum IgG2a antibody. Sera of both mercury‐ and saline‐treated mice immunized with HRBCs showed high titres of specific IgM, IgG1 and IgG2a anti‐HRBCs antibodies. Surprisingly, 3‐week treatment with mercury induced a reduction in the titres of specific IgG2a anti‐HRBCs antibodies in DBA/2 mice after immunization with HRBCs. Our results demonstrated that mercury did not induce a general immunosuppression or a biased Th1‐type immune response in resistant DBA/2 mice. The nonresponsiveness in mice resistant to mercury‐induced autoimmunity must be due to some other unknown mechanism(s).
Influence of Intestinal Microflora on Murine Bone Marrow and Spleen Macrophage Precursors
Authors: Nicaise  , Gleizes  , Sandre  , Forestier  , Kergot  , Quero  , Labarre
Published: March 2003

To investigate the adjuvant effect of intestinal flora on macrophage–colony‐stimulating factor‐responsive macrophage progenitors from spleen and bone marrow, we compared progenitor numbers and phenotypic characteristics of in vitro matured macrophages in germ‐free and flora‐associated mice (conventional, Escherichia coli‐monoassociated and conventionalized mice). The data obtained show that the flora affected differentially bone marrow and spleen progenitors. It increased the numbers of progenitors in the spleen but not in the bone marrow. It did not modify the expression of F4/80, Mac‐1 and major histocompatibility complex (MHC) class II on bone‐marrow‐derived macrophages (BMDM), while it clearly up‐regulated MHC class II expression on spleen‐derived macrophages (SDM). This effect was more pronounced in flora‐associated ex germ‐free mice than in conventional mice and it was greatly enhanced in the absence of M‐CSF. In vitro stimulation by lipopolysaccharide had no effect on marker expression of BMDM, while it decreased F4/80 and enhanced MHC class II molecules on SDM from germ‐free and flora‐associated mice. However, the expression of MHC class II remained lower in germ‐free mice. Enhancement of MHC class II molecule expression on SDM may contribute to the protective role of flora, because successful immune responses are dependent on the expression of these molecules.
Antibodies against Macaque Monoclonal Immunoglobulin G in Rheumatoid Arthritis
Authors: FORTENFANT  , GARRETTE‐GASTON  , OKSMAN  , FOURNIÉ  , BLANCHER
Published: March 2003

The presence of rheumatoid factors (RF) in the serum of rheumatoid arthritis (RA) patients is commonly evidenced by agglutination tests: the Waaler–Rose assay, based on the use of human red blood cells (RBCs) coated with rabbit anti‐RBC antibodies, and the latex test, which uses latex particles coated with denatured human immunoglobulin G (IgG). The aim of the present study was to characterize the RF able to agglutinate human RBCs coated with macaque antihuman RBC IgG antibodies secreted from macaque–mouse heterohybridomas (two from rhesus monkey and one from crab‐eating macaque). Human RBCs coated with macaque monoclonal antibodies (MacMoAbs) were used for agglutination tests and these were carried out in parallel with standard tests (Waaler–Rose and latex agglutination tests) on sera from 82 RA patients, 86 patients with other forms of inflammatory chronic arthritis and 47 healthy human subjects. MacMoAb‐coated RBCs identified RF in the sera of 66% patients with RA. By contrast, the frequency of positive sera in other inflammatory diseases was 5% and all 47 healthy controls were negative. Antimacaque IgG antibodies were found to be more specific for RF than standard tests, in the sera of patients with RA.
Alterations in Expression and in Serum Activity of Dipeptidyl Peptidase IV (DPP IV, CD26) in Patients with Hyporectic Eating Disorders
Authors: Hildebrandt  , Rose  , Mayr  , Schüler  , Reutter  , Salama  , Klapp
Published: March 2003

The notion that patients with eating disorders maintain a functional immunosurveillance in spite of severe malnutrition has attracted researchers for years. Dipeptidyl peptidase IV (DPP IV), a serine protease with broad tissue distribution and known activity in serum, operates in the cascade of immune responses. Membrane‐bound DPP IV expressed on lymphocytes, also known as the leucocyte antigen CD26, is considered to participate in T‐cell activation. We hypothesized that the activity of DPP IV in serum and expression of CD26 in lymphocytes may be altered in patients with eating disorders. Serum DPP IV activity and the number of CD26 (DPP IV)‐positive peripheral blood lymphocytes were measured in 34 patients [anorexia nervosa (AN): n = 11, bulimia (B): n = 23] in four consecutive weekly analyses. In addition, the expression of CD25 (interleukin‐2 receptor α chain) was evaluated to estimate the degree of T‐cell activation. The same analyses were carried out in healthy female volunteers (HC, n = 20). CD2‐CD26‐positive cells were reduced in patients compared with healthy controls [mean 40.2% (AN) and 41.1% (B) versus 47.4% (HC), P < 0.01], while the DPP IV activity in serum was elevated [mean 108.4 U/l (AN) versus 91.1 U/l (B) and 80.3 U/l (HC), P < 0.01]. The potential implications of our observations on, and beyond, immune function are discussed.
Is There a Maternally Induced Immunological Imprinting Phase à la Konrad Lorenz?
Authors: Lemke  , Lange
Published: March 2003

In mammals, IgG antibodies are transferred from mothers to the offspring. Since these maternal antibodies result mainly from thymus‐dependent immune responses which have undergone immune maturation through somatic hypermutations, they represent the highest quality of the collective maternal immunological experience. Maternal antibodies not only confer passive immunity as long as the newborn's immune system has not fully developed, but also exert an active stimulation as indicated by their regulatory influence on isotype expression, long‐term idiotypic alterations, determination of the adult B and T cell repertoire, induction of antigen reactive IgM as well as an affinity enhancement of a proportion of early primary antibodies. The fact that several of these features can only be induced during limited sensitive periods shortly after birth is reminiscent of the behavioural imprinting as defined by Konrad Lorenz. We therefore propose that during early ontogeny there is an immunological imprinting phase with characteristics analogous to behavioural imprinting: (i) the internal imprinting effect is induced by external signals, (ii) in contrast to normal learning, immunological imprinting is also only possible during certain development phases and (iii) it is characterised by an (almost) irreversible result. Hence, if particular immunological experiences are only possible during such sensitive phases, maternal immunoglobulins and consequently the mother's immunological experience is of prime importance for the start of the ontogenetic development of the immune system.
Invertebrates versus Vertebrates Innate Immunity: In the Light of Evolution (‘Nothing in biology makes sense except in the light of evolution’ T. Dobzhansky, Amer Biol Teacher 1973;35:125–9)
Authors: Rinkevich
Published: March 2003

Invertebrates use a nonadaptive, innate immunity, the expression of germline encoded receptors, to identify the allogeneic and xenogeneic attributes. Vertebrates also have the capacity to express ontogenically related adaptive immunity which is a somatically selected gene rearrangement process. Several commonly accepted generalizations are utilized to explain the enigmatic lack of the adaptive immunity in invertebrates. All point to the primitive nature of the innate immunity and the primitive organization of the body plan and the life history patterns of invertebrates. Seven of the most common generalizations are reviewed and confuted by virtue of a biased literature presentation. Subsequently, three evolutionary puzzles are raised and the accepted paradigm that the vertebrate immunity is pathogenically directed is further challenged. This leads to an alternative idea suggesting that preserving the individuality against the threat of invading conspecific cells might have been the original function of the immune system. This ancient system has been co‐opted later on to serve as a defence mechanism against pathogens. The secondary role arose in the form of a multiplicity of newly developed phenomena, one of them being the vertebrate adaptive immunity. This proposal is supported by the fact that vertebrates still exhibit two distinct but common types of naturally occurring transplantation events (natural chimerism) and by a variety of recent studies, providing evidence for the crucial role of the vertebrate's innate immunity in signalling and triggering the acquired effector mechanisms.
Demonstration of Expression of Six Proteins of the Mammalian Cell Entry (mce1) Operon of Mycobacterium tuberculosis by Anti‐Peptide Antibodies, Enzyme‐Linked Immunosorbent Assay and Reverse Transcription–Polymerase Chain Reaction
Authors: Harboe  , Christensen  , Haile  , Ulvund  , Ahmad  , Mustafa  , Wiker
Published: March 2003

Polyclonal rabbit antibodies were generated to synthetic peptides corresponding to predicted B‐cell epitopes of six proteins of the mce1 operon of Mycobacterium tuberculosis. Antipeptide antibodies reacted with Mce1A and Mce1E fusion proteins in sonicates of recombinant Escherichia coli as well as with distinct bands in sonicates, but not in culture fluids of M. tuberculosis and M. bovis bacillus Calmette–Guérin (BCG). Polyvalent rabbit antibodies generated by immunization with sonicates of BCG bacilli reacted with synthetic peptides from the six Mce1 proteins on the solid phase in enzyme‐linked immunosorbent assay (ELISA), albeit with different frequencies. The Mce1A peptide (p124–140) reacted most frequently, with seven of the nine antibodies tested, while the Mce1F peptide (p329–343) reacted with two. Used as a control, 20 polyclonal rabbit antibodies to 12 isolated proteins of M. tuberculosis and M. bovis BCG did not react with any of the six synthetic peptides, except in one case. mRNA expression of the six mce1A–mce1F genes of M. tuberculosis was demonstrated by reverse transcription–polymerase chain reaction (RT–PCR). These data indicate that all Mce1A–Mce1F proteins of the mce1 operon are expressed by in vitro‐grown M. tuberculosis and M. bovis BCG.
Dendritic Cells Induce CD4+ and CD8+ T‐Cell Responses to Mycobacterium bovis and M. avium Antigens in Bacille Calmette Guérin Vaccinated and Nonvaccinated Cattle
Authors: Hope  , Kwong  , Sopp  , Collins  , Howard
Published: March 2003

Few data are available regarding the induction of memory T‐lymphocyte responses in cattle following Bacille Calmette Guérin (BCG) vaccination. Studies of the immune response induced by BCG vaccination provide an insight into the basis of antimycobacterial immunity that could be exploited for the development of more effective vaccination strategies. We used autologous dendritic cells (DC) infected with Mycobacterium bovis Bacille Calmette Guérin (BCG) or pulsed with purified protein derivative from M. bovis (PPD‐B) or M. avium (PPD‐A) to assess responses of CD4+, CD8+ and WC1+γδ TCR+ lymphocytes from BCG vaccinated and nonvaccinated cattle. Mycobacteria‐specific CD4+ and CD8+, but not WC1+γδ TCR+, memory T lymphocytes were demonstrated in BCG‐vaccinated cattle. CD4+ and CD8+ lymphocytes proliferated and produced interferon (IFN)‐γ in response to BCG‐infected or PPD‐B‐pulsed DC. Proliferative responses were greater for CD4+ than CD8+ lymphocytes, although secretion of IFN‐γ was higher from the CD8+ T cells. Responses to PPD‐A‐pulsed DC were lower, with no CD8+ response. Lymphocytes from nonvaccinated calves were also stimulated to proliferate by BCG‐infected DC, although the magnitude of proliferation was lower. The findings suggest that immunity to M. bovis induced by BCG vaccination in cattle may involve CD8+ memory T cells which produce IFN‐γ, as well as CD4+ memory T cells.
Pax‐5 and EBF are Expressed in Committed B‐Cell Progenitors Prior to the Colonization of the Embryonic Bursa of Fabricius*
Authors: Nieminen P. , Liippo J. , Lassila O.
Published: March 2003

The committed B‐cell precursors developing from hemopoietic stem cells have been considered to differentiate through a common lymphoid progenitor stage in the mouse. In the chicken B‐cell system, however, the committed B‐cell progenitors burst as a single wave prior to the bursal colonization and most likely as direct descendants of hemopoietic stem cells. In the present report we show that prebursally committed B‐cell progenitors specifically express early B‐cell factor (EBF) and Pax‐5 transcription factors. In addition we show that the expression of these and other B‐lineage‐associated transcription factors starts early in the chicken ontogeny. Altogether our findings strongly support the model of early delineation of B‐ and T‐cell development and do not support the existence of common lymphoid stem cells.
T‐Cell Receptor Downregulation by Ceramide‐Induced Caspase Activation and Cleavage of the ζ Chain
Authors: Menné C. , Lauritsen J. P. H. , Dietrich J. , Kastrup J. , Wegener A.‐M. K. , Andersen P. S. , Ødum N. , Geisler C.
Published: March 2003

Regulation of T‐cell receptor (TCR) cell surface expression levels is probably an important mechanism by which T‐cell responsiveness is controlled. Previously, two distinct pathways for TCR downregulation have been described. One is dependent on protein kinase C (PKC) and the leucine‐based receptor‐sorting motif (l‐based motif) of the CD3γ chain but independent of tyrosine kinases, whereas the other is dependent on the tyrosine kinase activation but independent of the PKC and the CD3γl‐based motif. In this study, we describe a new pathway for TCR downregulation distinct from both the PKC/CD3γl‐based motif‐dependent and the tyrosine kinase‐dependent pathways. This pathway is dependent on ceramide‐induced activation of caspases and correlate with caspase‐mediated cleavage of the ζ chain. Thus, a 10–15% downregulation of the TCR was induced following the treatment of the T cells with ceramide for 4 h. A close correlation between TCR downregulation, caspase activation, and cleavage of the ζ chain was found. Furthermore, the caspase inhibitors abolished the cleavage of the ζ chain and TCR downregulation in parallel with the inhibition of the caspase activity.
Sirolimus Interferes with the Innate Response to Bacterial Products in Human Whole Blood by Attenuation of IL‐10 Production
Authors: Jørgensen P. F. , Wang J. E. , Almlöf M. , Solberg R. , Okkenhaug C. , Scholz T. , Thiemermann C. , Foster S. J. , Aasen A. O.
Published: March 2003

Current immunosuppressive strategies are aimed at abrogating the allospecific T‐cell response against donor tissues or organs. However, little information is yet available on the potential influences of these drugs on innate immune responses. In order to address this, we have employed a whole blood model. Human whole blood was pretreated with sirolimus, cyclosporine A or tacrolimus in therapeutic as well as supra therapeutic doses, and subsequently stimulated with lipopolysaccharide (LPS), peptidoglycan (PepG) or lipoteichoic acid (LTA). Plasma cytokine analyses revealed a potent inhibitory effect of sirolimus on interleukin(IL)‐10 production induced by all bacterial products tested. In contrast, cyclosporine A and tacrolimus inhibited the tumour necrosis factor (TNF)‐α production in response to LPS, but not to PepG and LTA. Using a quantitative mRNA analyses, we also observed that sirolimus significantly decreased the IL‐10 mRNA accumulation to sub‐basal levels in peripheral blood mononuclear cells (PBMC). This suggests that the sirolimus inhibits IL‐10 production by interfering with the IL‐10 gene transcription. However, the molecular mechanism of this inhibition remains unclear. Based on the present study and observations by others, we postulate that the clinical use of the sirolimus may be associated with a dysregulated innate immune response to bacterial infection and thus an increased risk of hyperinflammation and sepsis.
Binding, Trafficking and Accumulation of Serum Amyloid A in Peritoneal Macrophages
Authors: Kluve–beckerman B. , Manaloor J. , Liepnieks J. J.
Published: March 2003

Murine serum amyloid A1.1 (SAA1.1) has been conjugated with the fluorophore Texas Red (TxR), and its interaction with peritoneal macrophages has been visualized by scanning confocal microscopy. Binding of TxR–SAA to cell surfaces was inhibited by an excess of unlabelled SAA indicating the involvement of saturable receptors. Internalized TxR–SAA was seen initially as small punctate signals which in some cells evolved into a fine fluorescent network, a pattern typical of tubular endosomes. Colocalization of TxR–SAA with Cy5‐labelled low density lipoprotein (LDL) but not with Oregon Green‐labelled transferrin suggested that SAA trafficked through endosomes and lysosomes for degradation rather than through recycling compartments. Consistent with this catabolic pathway, macrophages loaded with TxR–SAA lost fluorescence within several days after being shifted to a fluorophore‐free medium. In sharp contrast to this, cells maintained under amyloid‐forming conditions, i.e. in the presence of unlabelled SAA and amyloid‐enhancing factor (AEF) before and after treatment with TxR–SAA, remained brightly fluorescent over the course of 5 days. Immunocytochemistry verified the accumulation of SAA within macrophages. These findings support the hypothesis that a decreased catabolism of internalized SAA plays a role in AA amyloid pathogenesis.