Functional characterization of partial recombinant goat conglutinin: Its role as innate immunity marker and use as antigen in sandwich ELISA.

Conglutinin, a liver synthesized versatile innate immune marker consisting C-type lectin domain belongs to collectin superfamily of proteins. The protein, first detected in bovine serum as soluble pattern recognition receptor (PRR) has wide range of antimicrobial activities. In the present study, open reading frame (ORF) encoding neck and carbohydrate recognition domain (NCRD) of goat conglutinin gene ligated to the vector pRSET-A was expressed in E. coli BL-21(pLys) cells. The 27 kDa recombinant protein (rGCGN) purified by single step Ni+2 -NTA affinity chromatography was found to cross-react with recombinant anti-buffalo conglutinin antibody raised in poultry. Further, it displayed calcium-dependant sugar binding activity towards yeast mannan and calcium-independent binding activity towards LPS. The mannan binding activity of rGCGN was inhibited in the presence of N-acetyl-glucosamine because of higher affinity towards this sugar. The recombinant protein was found to stimulate production of superoxide ions and hydrogen peroxide in goat neutrophils, which are instrumental in stimulating phagocytic activity of cells. When used as antigen in Sandwich ELISA, straight line (Y = 0.299x + 0.067, R2 = 0.997) was observed within the concentration range of 200-1000 ng/100 µl of rGCGN. Using this equation, the native conglutinin concentration in goat sera was estimated to be 0.5-7.5 µg/ml. The results indicated that prokaryotically expressed functionally active rGCGN can be used as antigen to assess native serum conglutinin levels in Sandwich ELISA and as immunomodulator in therapeutic applications to sequester unwanted immune complexes from the circulation.

Preoperative albumin-to-globulin ratio predicts survival in patients with non-small-cell lung cancer after surgery.

The prognostic value of the preoperative albumin-to-globulin ratio (AGR) has not been investigated in non-small-cell lung cancer (NSCLC). Therefore, we aimed to assess the clinical applicability of the preoperative AGR to predict the prognosis in patients with NSCLC. We retrospectively enrolled 545 patients with stage I/II/III NSCLC who underwent surgery at our institution. The cutoff value for preoperative AGR was calculated by using a receiver operating characteristic curve analysis. A low AGR was associated with several clinicopathological variables related to tumor progression. In the multivariate analyses, the preoperative AGR was identified as an independent prognostic factor for disease-free survival (DFS; P = 0.003) and overall survival (OS; P = 0.005). For patients with stage II and III with a preoperative AGR ≤ 1.43, the surgery plus chemotherapy group had a significantly longer DFS and OS than the surgery alone group (P = 0.002 and P = 0.001, respectively); however, a significant difference in DFS and OS between these two groups was not observed in patients with stage II and III with an AGR > 1.43 (P = 0.808 and P = 0.842, respectively). The preoperative AGR is an independent, significant predictor of DFS and OS in patients with NSCLC. Our results also demonstrate that the preoperative AGR might be a predictive marker of the therapeutic effect of postoperative chemotherapy in patients with stage II and III NSCLC.

Collectins and galectins in the abomasum of goats susceptible and resistant to gastrointestinal nematode infection.

Originally described in cattle, conglutinin belongs to the collectin family and is involved in innate immune defense. It is thought that conglutinin provides the first line of defense by maintaining a symbiotic relationship with the microbes in the rumen while inhibiting inflammatory reactions caused by antibodies leaking into the bloodstream. Due to the lack of information on the similar lectins and sequence detection in goats, we characterized the goat conglutinin gene using RACE and evaluated the differences in its gene expression profile, as well as in the gene expression profiles for surfactant protein A, galectins 14 and 11, interleukin 4 and interferon-gamma in goats. We used Saanen and Anglo Nubian F2 crossbred goats monitored over a period of four months and characterized them as resistant (R) or susceptible (S) based on the average values of EPG counts. Goat conglutinin was similar to bovine conglutinin, but its gene expression varied among different tissues. However, as with bovine conglutinin, it was most highly expressed in the liver. Variation in conglutinin (R=24.3±3.9; S=23.5±2.6, p=0.059), protein surfactant A (R=23.8±5.2, S=24.4±2.3, p=0.16), galectin 14 (R=15.9±3.5, S=14.7±6.2, p=0.49) and galectin l1 gene expression (R=25.4±2.6, S=25.8±3.7, p=0.53) was not significant between groups. However, there were weak correlations between interleukin 4 and the protein surfactant A gene (r=0.459, p=0.02) and between interleukin 4 and galectin 11 (r=0.498, p=0.01). Strong correlation between interferon-gamma and galectin 14 (r=0.744, p=0.00) was observed. Galectin 14 was negatively correlated with the number of nematodes in the goat (r=-0.416, p=0.04) as well as the EPG count (r=-0.408, p=0.04). This is the first study to date that identifies the gene expression of conglutinin, surfactant protein A and galectins 14 and 11 in the goat abomasum. In conclusion, we present evidence that lectin is involved in the immune response to gastrointestinal nematodes, which suggests that collectins and galectins are involved in the molecular recognition of helminths.

Pharmacokinetic and Pharmacodynamic Investigations of ION-353382, a Model Antisense Oligonucleotide: Using Alpha-2-Macroglobulin and Murinoglobulin Double-Knockout Mice.

To investigate the pharmacokinetics (PKs) and pharmacodynamics (PDs) for ION-353382, an antisense oligonucleotide (ASO) targeting scavenger receptor class B type I (SRB1) mRNA, using alpha-2-macroglobulin (A2M), murinoglobulin double-knockout (DKO), and wild-type mice. Wild-type and DKO homozygous mice were administered a single subcutaneous injection of ION-353382 at 0, 5, 15, 30, and 60 mg/kg. Mice were sacrificed at 72 h with plasma and organs harvested. Both liquid chromatography-mass spectrometry (LC-MS) and enzyme-linked immunosorbent assay (ELISA) were used to determine ASO exposure with real-time PCR for SRB1 expression. Immunohistochemistry was evaluated to explore hepatic uptake of ASOs. The total plasma protein binding and profiling was assessed. Finally, two-dimensional gel electrophoresis identified protein expression differences. PK exposures were comparable between wild-type and DKO mice in plasma, liver, and kidney, yet a near twofold reduction in EC50 was revealed for DKO mice based on an inhibitory effect liver exposure response model. Total plasma protein binding and profiling revealed no major dissimilarities between both groups. Plasma proteome fingerprinting confirmed protein expression variations related to A2M. Histological examination revealed enhanced ASO distribution into hepatocytes and less nonparenchymal uptake for DKO mice compared to wild-type mice. Knocking out A2M showed improved PD activities without an effect on total plasma and tissue exposure kinetics. Binding to A2M could mediate ASOs to nonproductive compartments, and thus, decreased binding of ASOs to A2M could potentially improve ASO pharmacology.

Prokaryotic expression of ovis aries conglutinin encoding neck and carbohydrate recognition domain and its functional characterization.

Conglutinin, a soluble pattern recognition receptor of innate immune system in bovines is known for its potential defensive activity against microorganisms either by direct agglutination in the presence of calcium or by acting as opsonin. In the present study, sheep (Ovis aries) conglutinin encoding neck and carbohydrate recognition domain (rSCGN) was expressed in the E coli BL21 expression host. The recombinant conglutinin revealed molecular weight of 27 kDa in SDS PAGE and also in western blotting using antibuffalo conglutinin polyclonal serum. The protein was characterized further for its functional activity in various assays. In ELISA based sugar and LPS binding assay, the rSCGN revealed its high binding activity toward N-acetyl glucosamine and E. coli LPS in the presence and the absence of calcium ions, respectively. Hemagglutination of chicken red blood cells caused by Newcastle disease virus was not inhibited in the presence of rSCGN as it lacked complete collagenous region present in the native protein. In virus neutralization test, the recombinant protein was found to reduce multiplication of bovine herpes virus-1 propagated in MDBK cells. This prokaryotically expressed 27 kDa recombinant sheep conglutinin can serve as antigen in future studies to develop sandwich ELISA for assessing the level of native conglutinin in sheep serum.

Sequence-based appraisal of the genes encoding neck and carbohydrate recognition domain of conglutinin in blackbuck (Antilope cervicapra) and goat (Capra hircus).

Conglutinin, a collagenous C-type lectin, acts as soluble pattern recognition receptor (PRR) in recognition of pathogens. In the present study, genes encoding neck and carbohydrate recognition domain (NCRD) of conglutinin in goat and blackbuck were amplified, cloned, and sequenced. The obtained 488 bp ORFs encoding NCRD were submitted to NCBI with accession numbers KC505182 and KC505183. Both nucleotide and predicted amino acid sequences were analysed with sequences of other ruminants retrieved from NCBI GenBank using DNAstar and Megalign5.2 software. Sequence analysis revealed maximum similarity of blackbuck sequence with wild ruminants like nilgai and buffalo, whereas goat sequence displayed maximum similarity with sheep sequence at both nucleotide and amino acid level. Phylogenetic analysis further indicated clear divergence of wild ruminants from the domestic ruminants in separate clusters. The predicted secondary structures of NCRD protein in goat and blackbuck using SWISSMODEL ProtParam online software were found to possess 6 beta-sheets and 3 alpha-helices which are identical to the result obtained in case of sheep, cattle, buffalo, and nilgai. However, quaternary structure in goat, sheep, and cattle was found to differ from that of buffalo, nilgai, and blackbuck, suggesting a probable variation in the efficiency of antimicrobial activity among wild and domestic ruminants.

Association of genetic polymorphisms with histological grading of necroinflammation, staging of fibrosis, and liver function in Mexicans with chronic hepatitis C virus infection.

BACKGROUND/AIM: The aim of this work was to establish an association between the single-nucleotide polymorphisms (SNPs) of TGFB1 (rs1800471), AT (rs3789679), MMP-1 (rs17886084), MMP-3 (rs35068180), and PAI-1 (rs1799889) and the histological grading of necroinflammation, staging of hepatic fibrosis, and liver function in Mexican patients with advanced liver fibrosis due to chronic hepatitis C virus infection. METHODS: AT, MMP-1, MMP-3, and PAI-1 gene polymorphisms were analyzed by polymerase chain reaction in real time, whereas TGFB1 polymorphism was detected by polymerase chain reaction-based restriction fragment length polymorphism in 38 patients with established advanced liver fibrosis and 50 subjects from the general population. Grading of necroinflammation and staging of liver fibrosis were assessed by liver biopsy and graded according to modified histological activity index Ishak score. RESULTS: Regarding TGFB1 SNP, significant differences were found between G/G and G/C genotypes of patients with hepatic necroinflammation (P = 0.05) and hepatic fibrosis (P = 0.002). There were also significant differences among genotypes of patients with the AT SNP in hepatic necroinflammation (P = 0.01). The albumin-globulin ratio between genotypes of patients with the MMP-3 SNP gene showed significant differences (P = 0.02). CONCLUSION: Our findings demonstrate that a specific combination of genotypes associated with biochemical values and a histological high score determine more severe liver disease. The presence of the G/G genotype of TGFB1 SNP in patients was significantly associated with severity of liver necroinflammation and fibrosis. Patients with the G/G genotype of AT SNP were associated with severe necroinflammation. The albumin-globulin ratio was increased in patients with the 6A allele of MMP-3 SNP. These results might contribute to diagnosis and further establishment of liver disease treatment.

Genome-wide association study of serum albumin:globulin ratio in Korean populations.

Low albumin:globulin (A/G) ratios are associated with vascular adverse events, nephrotic syndrome and autoimmune disease. Genome-wide association studies (GWASs) have been identifying genetic variants associated with total serum protein, serum albumin and globulins, but A/G ratio has never been considered the target phenotype. To identify the genetic basis of the A/G ratio, we performed a GWAS on A/G ratio in 4205 individuals from the Ansan cohort and confirmed the results in 4637 subjects from the Ansung cohort. The single-nucleotide polymorphism (SNP) genotypes of Affymetrix SNP array 5.0 were obtained from the Korean Association Resource Consortium, and we selected 290 659 common SNPs with a minor allele frequency >0.05. Genetic factors for A/G ratio were analyzed by linear regression analysis, controlling for age, sex, body mass index, smoking status and alcohol drinking status as covariates. From the GWAS of the Ansan cohort, we identified two significant genome-wide signals (P-values<5 × 10(-8)) and 36 moderate signals (P-value<1.0 × 10(-4)). These 38 signals were tested in the Ansung population. Eleven SNPs from six loci (GALNT2, IRF4, HLA-DBP1, SLC31A1, FADS1 and TNFRSF13B) were replicated, with P-values<0.05. The most compelling association was observed in the TNFRSF13B locus on chromosome 17p11.2 (SNP: rs4561508), with an overall combined P-value=7.80 × 10(-24). The other significant signal was observed on chromosome 11q12.2-the FADS1 locus (SNP: rs174548)-with an overall combined P-value=3.54 × 10(-8).

Plasma elimination kinetics for factor VII are independent of its activation to factor VIIa and complex formation with plasma inhibitors.

The mechanism for the elimination of factor VII (FVII) from the circulation is unknown, just as it is unclear how activation of FVII to FVIIa and subsequent complex formation with antithrombin III (AT) or alpha2-macroglobulin (alpha2M) affects clearance. The possibility that the clearance mechanism involves activation and inhibitor complex formation as obligatory intermediate reactions is examined in this study. Human and murine sera were spiked with human FVIIa in the absence and presence of heparin and analysed for complex formation. Complex formation in vivo was studied after intravenous injection of (125)I-VIIa in mice; and the pharmacokinetics (PK) of human and murine FVIIa was studied in normal mice. Furthermore, comparative PK studies were performed with FVII, FVIIa, active site blocked FVIIa and a preformed FVIIa-AT complex in normal and alpha2M-deficient mice. The data demonstrated that FVIIa-AT complexes and to a much lesser extent FVIIa-alpha2M-complexes accumulated in vivo after FVIIa administration. FVIIa-AT accounted for about 50% of total FVIIa antigen left in the circulation after 3 hours. All FVII derivatives studied including FVII, FVIIa and FVIIa-AT were cleared with similar rates suggesting an elimination kinetics which is unaffected by FVII activation and subsequent inactivation by plasma inhibitors.

The immune and stress responses of Atlantic cod to long-term increases in water temperature.

Sea-caged cod are limited in their movements in the water column, and thus can be exposed to large seasonal ( approximately 0-20 degrees C) temperature fluctuations. To investigate the physiological response of Atlantic cod to summer-like increases in temperature, we exposed 10 degrees C acclimated juvenile cod to a graded thermal challenge (1 degrees C increase every 5 days) and measured: (1) plasma cortisol and glucose levels; (2) the respiratory burst activity of blood leukocytes; and (3) the expression of specific immune-related genes [MHC Class I, Interleukin-1beta (IL-1beta), beta2-microglobulin (beta2-M), Immunoglobulin M (IgM)-light (L) and -heavy (H) chains] in the blood using quantitative reverse transcription-polymerase chain reaction (QRT-PCR). The experiment was stopped at 19.1 degrees C, with 26.7% of the fish surviving to this point. Plasma glucose levels increased slightly at 16 and 18 degrees C (by 1.39- and 1.74-fold, respectively), in contrast, cortisol levels were elevated significantly (by 2.9-fold) at 16 degrees C but returned to control levels thereafter. The effect of increasing temperature on the expression of immune related genes in blood cells (leukocytes) was variable and depended on the gene of interest. The expression of IgM-H remained stable for the duration of the experiment. In contrast, IL-1beta expression was increased significantly (by approximately 25-fold) at 19 degrees C as compared to time-matched control fish, and changes in the expression of beta2-M, MHC Class I and IgM-L followed a pattern similar to that seen for cortisol: increasing at 16 degrees C (by 4.2-, 5.3- and 17-fold, respectively), but returning to pre-stress levels by 19 degrees C. Interestingly, increasing temperatures had no effect on respiratory burst activity. This study is the first to examine the effects of a chronic regimen of increasing temperature on the stress physiology and immunology of a marine teleost, and suggests that immune function is influenced by complex interactions between thermal effects and temperature-induced stress (elevated circulating cortisol levels).

Conglutinin, CL-43 and CL-46--three bovine collectins.

Conglutinin, collectin-43 (CL-43) and collectin-46 (CL-46) are serum proteins characteristic for Bovidae. They belong to collectins--family of oligomeric proteins composed of trimeric subunits containing collagen-like sequences joined to C-type lectin domains. The genes encoding conglutinin, CL-43 and CL-46 are located on the bovine chromosome 28, and phylogenetic analysis indicates their common origin--from the lung surfactant protein D gene. Northern blot or immunocytochemical analysis confirm biosynthesis of bovine collectins mainly in the liver (conglutinin, CL-43) and in the thymus (CL-46). The level of conglutinin in the serum of dairy cows depends on many factors such as breeding, the season of the year, the stage of the reproductive cycle and infection. The collectins are involved in the innate immune defense. They bind to microbial surface carbohydrates inducing aggregation and, thereby, impeding infectivity. On the other hand the destruction of pathogens occurs due to stimulation of effector cells. CL-43 as well as conglutinin, binds to the collectin receptor (C1qR) localized on many types of cells identified as a surface variant of calreticulin. Conglutinin and CL-43 show antiviral activities towards influenza A virus and rotaviruses. Conglutinin also displays protective activity against bacterial infections.

Identification of potentially cross-reactive peanut-lupine proteins by computer-assisted search for amino acid sequence homology.

BACKGROUND: Allergic cross-reactions are an issue of major concern because of implications for public health. The molecular basis of cross-allergy is the similarity of epitopes belonging to proteins of different organisms. Lupine is an emerging cause of food allergy, which has become a 'hot topic' because of recent large-scale introduction into processed foods and frequent cross-reactions with other members of the legume family. However, no lupine allergen has been characterized thus far. Prompted by a recently reported case of peanut-lupine cross-allergy, we wished to identify the possible cross-reactive allergen(s) between the two vegetal species. METHODS: We used computer-aided amino acid sequence comparison, a well-established technique for the study of protein homology, and followed the FAO/WHO guidelines for the identification of potential allergens. We also performed a three-dimensional modeling of the suspected cross-reactive proteins to compare their molecular surfaces. RESULTS: We found a highly significant sequence homology and molecular similarity between allergen Ara h 8 of peanut and pathogenesis-related protein PR-10 of white lupine. Another protein of lupine, the beta-conglutin precursor, was found to be significantly homologous to the Ara h 1 allergen of peanut. The molecular surfaces of Ara h 8 and PR-10 were remarkably similar. CONCLUSIONS: Our in silico data allow to predict the allergenicity of PR-10 and beta-conglutin precursor of white lupine according to FAO/WHO guidelines. Amino acid sequence homology also suggests that these proteins could be responsible, at least in part, for some of the allergic cross-reactions between peanut and lupine reported in the literature.

The genes encoding bovine SP-A, SP-D, MBL-A, conglutinin, CL-43 and CL-46 form a distinct collectin locus on Bos taurus chromosome 28 (BTA28) at position q.1.8-1.9.

Collectins are a group of C-type lectins involved in the innate immune system, where they mediate and modulate clearance of pathogens. The health status of cattle is of major economical and ethical concern; therefore, the study of bovine collectins is of importance. The collectins conglutinin, CL-43 and CL-46 are only present in Bovidae and the characterization of their genes indicates that they are structural descendants of another collectin, lung surfactant protein D (SP-D). In this study, we assembled BAC clones into a contig spanning 330-1150 kb, which includes the bovine genes encoding the collectins SP-A (SFTPA), SP-D (SFTPD), mannan-binding lectin A (MBL1), CL-43 (COLEC9), CL-46 (COLEC13) and conglutinin (COLEC8). In the same contig, we also identified a gene that potentially encodes a novel conglutinin-like collectin (COLEC14). The arrangement of STFPA, SFTPD and MBL1 is homologous to the organization found in humans and mice, whereas the Bovidae-specific collectin genes, COLEC8, COLEC9 and COLEC13, extend from SFTPD. Proximal to the collectin locus at BTA28q1.8-1.9, and included in the contig, we found the microsatellite IDVGA8, which may be a valuable marker for tracking polymorphisms in the linked collectin genes.

Genomic and molecular characterization of bovine surfactant protein D (SP-D).

Collectins are a group of C-type lectins involved in the innate host defense against pathogens. They selectively recognize non-self glyco-conjugates on the surface of microorganisms and induce lysis, agglutination, and phagocytosis to eliminate invading microorganisms. With the perspective of being able to identify surfactant protein D (SP-D) polymorphisms associated with immune-compromised phenotypes in cattle, we have characterized the gene encoding bovine SP-D and its proximal promoter. Cloning and sequencing of the bSP-D gene, including the complete 5'-untranslated sequence, reveal that the gene comprises nine exons spanning approximately 10.5 kb with an organization resembling the bovine conglutinin gene. The gene localizes to the same locus as the conglutinin gene on Bos taurus chromosome 28 at position q1.8, which also includes the genes encoding CL-43 and CL-46. Several potential cis-regulatory elements, similar to elements known to regulate the transcription of human SP-D, were identified in the 5'-upstream sequence. RT-PCR analysis revealed that bovine SP-D is heavily expressed in the lung and the trachea, but also in segments of the gastrointestinal tract, the mammary glands and the salivary glands. By genotyping we assigned two potential polymorphisms leading to variations in the amino acid composition of the carbohydrate recognition domain (242 Glu/Val and 268 Ala/Gly).

Genomic and molecular characterization of CL-43 and its proximal promoter.

Collectins are part of the innate immune system as they bind nonself glycoconjugates on the surface of microorganisms and inhibit infection by direct neutralization, agglutination or opsonization of the invaders. Conglutinin and CL-43 are serum proteins that have only been found and characterized in Bovidae. We have studied molecular and genomic characteristics of CL-43 to identify polymorphisms that might be associated with disease-susceptible phenotypes or other traits in cattle, and to elucidate how the Bovidae may benefit from possessing additional collectins. Screening a bovine cDNA library resulted in the isolation of two plasmid clones that encoded the entire translated sequence of CL-43. The 5'-untranslated end and start point of transcription were identified by 5'-RACE and showed that the mRNA transcript comprises either 1326 or 1241 nucleotides because of alternative splicing. Both transcripts encode a protein of 321 amino acids including a signal peptide of 20 residues. Characterization of two overlapping genomic lambda phage clones showed that the gene comprised seven exons spanning 8.5 kbp. The CL-43 gene, like the conglutinin gene, was mapped to Bos taurus chromosome 28 at q1.8. The CL-43 promoter has 96% identity with the conglutinin promoter recently described by us, and the assignment of potential cis-regulatory elements shows that several hepatic transcription factors may regulate transcription in the acute phase response and in response to metabolic changes.

Lung surfactant protein D (SP-D) and the molecular diverted descendants: conglutinin, CL-43 and CL-46.

Lung surfactant protein D (SP-D), conglutinin, CL-43 and CL-46 belong to a group of proteins designated collectins that, besides a common structure made of a collagen-like region and a C-type lectin domain, are important components of the innate immune defence. They all bind complex glycoconjugates on microorganisms thereby inhibiting infection, enhancing the clearance by phagocytes and modulating the immune response. In addition, SP-D inhibits the generation of radical oxygen species or the propagation of lipid peroxidation. Knock-out mice deficient in SP-D have a disturbed homeostasis of pulmonary surfactant and suffer from oxidative stress leading to pulmonary inflammation upon microbial challenge. Conglutinin, CL-43 and CL-46 have in contrast to the rest of the collectin family only been found in cattle. During the characterization of the genes encoding conglutinin, CL-43 and CL-46 we observed several features showing that the additional bovine collectins are diverted molecular descendants of an ancestral SP-D gene. Since structural similarity often associates with common functionality, some of SP-D's effector mechanisms may apply to conglutinin, CL-43 and CL-46--and vice versa. This review focus on the structural and functional relationship of this group of collectins.

Cloning of hibernation-related genes of bullfrog (Rana catesbeiana) by cDNA subtraction.

Seven genes specifically expressed during hibernation in the bullfrog (Rana catesbeiana) were cloned from a subtracted cDNA library constructed from livers of winter bullfrogs. Those genes were fibrinogen alpha-subunit, fibrinogen gamma-subunit, complement component C3, alpha-1-microglobulin/bikunin precursor (AMBP), transferrin, apoferritin middle subunit and one novel gene. Northern hybridization has indicated that these seven genes were specifically induced or enhanced in winter. Above all, expression of the novel gene was specifically induced in winter in liver, though the expression of that was neither induced in bullfrog nor Xenopus laevis by cold treatment. The novel gene, which was designated as rc-hirp (Rana catesbeiana hibernation-related protein), encoded 420 base pairs length and a putative protein of 139 amino acid residues. Annual analyses of the expression of these genes have suggested that the seven winter-specific genes are playing an important role in hibernation processes.

Expression of the AMBP gene transcript and its two protein products, alpha(1)-microglobulin and bikunin, in mouse embryogenesis.

The expression pattern of the alpha(1)-microglobulin/bikunin precursor (AMBP) gene, and its two protein products were studied in mouse embryos of 8.5-15.5 days of embryonic development by in situ hybridization and immunohistochemistry. AMBP mRNA is strongly transcribed in liver parenchyma, pancreas, and intestine epithelium. Sites of weaker expression are the vessels of the umbilical cord, the developing vertebral bodies, and kidney. The alpha(1)-microglobulin and bikunin proteins are accordingly present in developing hepatocytes, pancreas, kidney, and gut. However, additional sites of protein distribution were found that do not correlate to mRNA localization: alpha(1)-microglobulin was found in myocytes and bikunin in cardiac muscle, nervous system microvasculature, and connective tissue. Both proteins were found in brain mesenchyme and meninges. Thus, a restricted expression of the AMBP mRNA in a few organs contrasts to a widespread and unique distribution of each of the two proteins.

Novel characterisation of the gene encoding conglutinin reveals that previously characterised promoter corresponds to the CL-43 promoter.

Conglutinin, a collectin found in bovine serum, is an opsonin that binds to glycoconjugates on the surface of microorganisms or on deposited iC3b, and acts in concert with phagocytes to establish a first-line of immune defense. We have isolated a genomic conglutinin phage clone and found that the 5'-flanking region shows 95.8% identity with the sequence previously published, which on the other hand shows 99.7% identity with the CL-43 promoter. We conclude that the previously published promoter corresponds to the CL-43 promoter and that the functional studies performed on it apply to transcription of CL-43. Comparison of potential cis-regulatory elements in relation to the functional studies indicates that the two genes are regulated by different mechanisms.

Increased Trypanosoma cruzi invasion and heart fibrosis associated with high transforming growth factor beta levels in mice deficient in alpha(2)-macroglobulin.

Trypanosoma cruzi proteinases are involved in host cell invasion in human patients and in mouse models. In mice, murine alpha(2)-macroglobulin (MAM) and murinoglobulin are circulating plasma proteinase inhibitors that also have important roles in inflammation and immune modulation. To define their role in experimental Chagas disease, we investigated the susceptibility to T. cruzi infection of mice that are deficient only in alpha2-macroglobulins (AM-KO) or in both MAM and monomeric murinoglobulin-1 (MM-KO), relative to the wild type (WT). Despite the high parasite load, parasitemia was lower in AM-KO and MM-KO mice than in WT mice. Nevertheless, we observed a significantly higher parasite load in the hearts of AM-KO and MM-KO mice, i.e., more amastigote nests and inflammatory infiltrates than in WT mice. This result demonstrates a protective role for MAM in the acute phase of murine T. cruzi infection. We further demonstrated in vitro that human alpha2-macroglobulins altered the trypomastigote morphology and motility in a dose-dependent way, and that also impaired T. cruzi invasion in cardiomyocytes. Finally, we demonstrated that the levels of transforming growth factor beta in AM-KO mice increased significantly in the third week postinfection, concomitant with high amastigote burden and important fibrosis. Combined, these in vivo and in vitro findings demonstrate that the MAM contribute to the resistance of mice to acute myocarditis induced by experimental T. cruzi infection.