Bounds on new Majoron models from the Heidelberg-Moscow experiment.
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Journal Article↗
Biomedical subjects
F Petry
Publications and source records attributed to F Petry.
The mouse C1q genes are clustered on chromosome 4 and show conservation of gene organization.
Mouse complement component C1q is a serum glycoprotein which consists of six A chains, six B chains and six C chains. The three polypeptides are 223, 228, and 217 residues long, respectively, and are encoded by three genes. DNA probes for mouse C1q A, B, and C chains were hybridized to Southern blots of DNA obtained from various inbred mouse strains. On the basis of fragment length polymorphisms, two different alleles of each of the genes could be identified. The distribution of these alleles was determined in the BXD and LXPL recombinant inbred strain series. Comparison with previously reported strain distribution patterns shows that the genes encoding mouse C1q map to the same locus on distal chromosome 4. Overlapping clones spanning the entire gene cluster of C1q were isolated from genomic libraries using specific cDNA probes. The three genes C1qA, C1qB, and C1qC are closely arranged on a 19 kilobase stretch of DNA in the 5' to 3' orientation A-C-B. Each gene consists of two exons separated by one intron. Sequence comparison of C1q from three different species have shown that the B chains have the strongest similarity. Southern blot analysis of chromosomal DNA from 14 vertebrate species demonstrated highest similarity between the C1qB genes, followed by C1qC and finally C1qA.
Amino Acid Sequence↗
Non-sense and missense mutations in the structural genes of complement component C1q A and C chains are linked with two different types of complete selective C1q deficiencies.
To shed light on the molecular basis of two different types of complete C1q deficiency, we performed extensive Southern blot analysis and sequenced all exons of the genes coding for the A, B, and C chains of C1q on two groups of deficient patients. In one family with three cases of complete C1q deficiency we found a point mutation in the codon for glutamine (CAG) at position 186 of the A chain that led to a termination codon (TAG). No gene products of any of the three genes were found in the patients' sera, indicating that full length polypeptides of the A, B, and C chains are required to form and secrete functional C1q. A second point mutation was found in a patient with a complete functional C1q defect. The abnormal C1q molecule had been shown to have a low m.w. of approximately 150,000 and a sedimentation coefficient of below 7S. The mutation occurred in the codon for glycine in position 6 of the C chain where a single base exchange (G-->A transition) has led to an arginine residue. In the parents and son of patient G we could demonstrate the heterozygous state of the mutation by the occurrence of both bases in question, G and A. The interruption of the collagen-like triplet motif Gly-X-Y and, even more likely, the introduction of a large positively charged side chain at the N-terminus of the polypeptide may inhibit the assembly of three structural subunits consisting of two A-B dimers and one C-C dimer to form the 11S C1q macromolecule.
Adult↗
Follicular dendritic cells, interdigitating cells, and cells of the monocyte-macrophage lineage are the C1q-producing sources in the spleen. Identification of specific cell types by in situ hybridization and immunohistochemical analysis.
In a mouse model, we have shown previously that macrophages are the principal source of complement C1q. Furthermore, spleen, heart, and brain were found to contain substantial levels of murine C1q-specific mRNA, whereas liver, kidney, lung, and small intestine contained only trace amounts of C1q-specific mRNA. This work addresses the identification of C1q-expressing spleen cells in the rat, using Northern blotting and in situ detection of rat C1q mRNA combined with immunohistochemical analysis. The complete sequence of mRNA encoding the B chain of rat C1q was established. The cloned cDNA was found to hybridize primarily with spleen-derived mRNA of 1.2 kb, and additionally with a novel mRNA species of 3 kb. In situ hybridization together with immunohistochemistry revealed most of the C1q-expressing cells to be located in the red pulp of the spleen, and to be mainly of the monocyte-macrophage lineage, as indicated by coexpression of ED-1, an established marker for this type of cell. In addition, C1q was expressed in S-100-positive but ED-1-negative cells, in germinal center follicular dendritic cells, and in some interdigitating dendritic cells of the periarteriolar lymphatic sheath (PALS). These results indicate that the spleen, containing the above APCs that are all involved to a major extent in the adaptive immune response and are all capable of synthesizing C1q that is involved intimately in the innate immune response, may provide the site at which the innate and adaptive immune systems merge.
Amino Acid Sequence↗
Expression of C1q, a subcomponent of the rat complement system, is dramatically enhanced in brains of rats with either Borna disease or experimental allergic encephalomyelitis.
In situ hybridization, RT-PCR and Northern blot analysis as well immunohistochemistry were used to examine the expression of C1q, a subcomponent of the rat complement system, in brains of rats infected with Borna disease virus (BDV) and rats afflicted with experimental allergic encephalomyelitis (EAE) induced by the adoptive transfer of myelin basic protein specific T cells. C1q mRNA, which was not detected in normal brain, became clearly detectable using RT-PCR analysis by d14 post infection (p.i.) with BDV. Maximal levels of C1q mRNA were reached 21 days p.i. when inflammatory reactions in the brain were also at a peak. Similarly, C1q mRNA was elevated when the clinical symptoms of EAE became evident 5 days following cell transfer. C1q positive cells, as identified by immunohistology, were preferentially localized in grey and white matter of the hippocampus and basolateral cortex. The C1q positive cells resembled microglial cells in morphology. The correlation of C1q expression with the development of neurological disease as well as the dramatic increase of C1q within brain regions with inflammatory lesions suggest that local biosynthesis of C1q may play a role in the pathogenesis of Borna virus induced and autoimmune encephalomyelitis.
Animals↗
Localization of parasite antigens in Cryptosporidium parvum-infected epithelial cells using monoclonal antibodies.
An immunogold ultrastructural study was made of Cryptosporidium parvum-infected intestinal cells from SCID mice to locate parasite antigens recognized by monoclonal antibodies raised against sporozoite or oocyst wall antigens. The results suggested that these antigens were present in more than one life-cycle stage and demonstrated that the intracellular parasite modified the parasitophorous vacuole membrane and villous membrane surrounding the parasite. In an immunofluorescence antibody test monoclonal antibody (MAb) 1B5 reacted with the oocyst wall, MAb 2C3 with the whole sporozoite and MAb 2B2 with the sporozoite surface. Western and dot-blot studies demonstrated that different carbohydrate epitopes were recognized by the respective sporozoite-reactive antibodies. In the ultrastructural examination MAb 1B5 reacted with macro- and microgametocytes as well as the oocyst wall. In the macrogametocyte MAb 1B5 recognized the large electron-dense bodies characteristic of this stage and, in some parasites, the parasitophorous vacuole and the parasite pellicle. The sporozoite-reactive MAbs were able to bind to all developmental stages. These antibodies recognized the parasite cytoplasm and, additionally, MAb 2B2 produced substantial labelling of the parasite membrane. Significantly, both these antibodies also detected antigen in the parasitophorous vacuole membrane and, to a lesser extent, the villous membrane surrounding the parasite.
Animals↗
Murine infection model for maintenance and amplification of Cryptosporidium parvum oocysts.
Propagation of Cryptosporidium parvum is problematic because in vitro development of the parasite is poor and animals are only briefly susceptible as neonates. At present oocysts of the parasite are usually procured by passage in neonatal sheep or cattle. In the present study, large numbers of oocysts of C. parvum could be isolated following infection of dexamethasone-treated adult C57BL/6 mice. The amount of immunosuppressive drug and the regimen of administration were critical for successful maintenance of the parasite, however. Routinely, 10 mice (age, 8 to 12 weeks) were injected four times on alternate days with 1.0 mg of dexamethasone, and the last injection was given on the same day as oral inoculation with 10(6) oocysts. By using a simplified procedure for oocyst purification from mouse feces, approximately 10(9) oocysts were obtained. This model is inexpensive and comparatively safe to handle, and the numbers of animals inoculated can be varied to obtain the required number of oocysts. Thus, this murine infection model would be a suitable alternative to the use of neonatal calves or sheep for efficient oocyst propagation.
Animals↗
Modulation of mRNA expression and secretion of C1q in mouse macrophages by anti-inflammatory drugs and cAMP: evidence for the partial involvement of a pathway that includes cyclooxygenase, prostaglandin E2 and adenylate cyclase.
Isolated BALB/c mouse thioglycollate-elicited (inflammatory) peritoneal macrophages release at least 10 times more C1q than do isolated resident peritoneal macrophages. Addition of non-steroidal anti-inflammatory drugs (NSAID) to thioglycollate-elicited macrophages in culture inhibited the release of C1q and reduced levels of C1q-specific mRNA. Contrastingly, the NSAID were found to enhance C1q-specific mRNA levels in resident macrophages, although no increase in C1q levels secreted was observed. This suggests that the response of macrophages to NSAID, with respect to C1q synthesis, reflects the developmental stage of the macrophage. The gold salt auranofin (AFN) was found to enhance markedly C1q synthesis at both transcriptional and secretory levels in thioglycollate-elicited macrophages whilst, conversely, AFN reduced mRNA levels in resident macrophages. This indicates that AFN and the NSAID may work via the same or similar biochemical pathway, but with opposing effects. The glucocorticoid hydrocortisone (HC) greatly enhanced C1q-specific mRNA levels in both thioglycollate-elicited and resident macrophages, although no parallel increases in C1q secreted were observed. The data on inhibition of C1q biosynthesis by NSAID in thioglycollate-elicited macrophages are supported by the enhancement of C1q biosynthesis following addition of prostaglandin E2 (PGE2) or dibutyryl cyclic AMP (dBcAMP) to the cultures. From these experiments, it is concluded that C1q biosynthesis is controlled, at least in part, by a pathway involving cAMP.
Adenylyl Cyclases↗
Investigation of the Majoron-accompanied double-beta decay mode of 76Ge.
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Journal Article↗
Complete functional C1q deficiency associated with systemic lupus erythematosus (SLE).
A complete functional deficiency of C1q is described in a patient suffering from SLE. From reduced plasma C1 activity of the parents a hereditary trait was assumed. The defective C1q molecule was haemolytically inactive, did not bind to immune complexes, and was not recognized by the monocyte C1q receptor. C1 activity in the patient's serum could be restored by the addition of purified C1q. Analysis by gel-filtration and ultracentrifugation experiments revealed an immunoreactive molecule of about 150 kD mol. wt, corresponding to one structural subunit of the C1q macromolecule, containing two A chain-B chain dimers and a C-C chain dimer. Applying Southern blot analysis with cDNA clones encoding for the three individual chains of the C1q molecule, no restriction fragment length polymorphism was detected, ruling out possible major alterations of the genetic information.
Adult↗
C1 associated and related proteins: sequence data.
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Amino Acid Sequence↗
The phylogeny and evolution of the first component of complement, C1.
Extensive study of the phylogeny and evolution of the complement system has always been hampered by the difficulties involved in functional assays. These tests rely on the compatibility of the components from different species. Whereas all mammalian species appear to have almost identical classical, alternate and lytic pathways, non-mammalian vertebrates show minor differences. The source of the immunoglobulin molecule used to demonstrate classical pathway activation has also been shown to be crucial. The use of antibodies directed against complement components has been beneficial in the study of relationships, but cross-reactivity with non-complement proteins limited their use. The isolation and purification of complement components and the biochemical characterisation including amino acid analysis and peptide sequencing resulted in an enormous increase in our knowledge of the evolution of the complement system. Amino acid sequence analysis together with gene cloning of all human complement components finally revealed a number of sofar unknown features concerning the domain structure of the components and the relation of certain motifs and repeats to other proteins. The use of cDNA probes in Southern blot analysis of chromosomal DNA from various species enabled an extension of our scope of the phylogeny of complement. In this article we summarized the data on the phylogeny and evolution of the first component of complement and the associated molecules. We provide evidence for the conservation of the classical pathway and C1q in particular which appears to predate the divergence of the cartilaginous fish from the higher vertebrates. The possibility that the classical pathway could predate the alternate pathway is discussed.
Amino Acid Sequence↗
Isolation, sequence analysis and characterization of cDNA clones coding for the C chain of mouse C1q. Sequence similarity of complement subcomponent C1q, collagen type VIII and type X and precerebellin.
A mouse macrophage lambda gt11 cDNA library was screened using a genomic DNA clone coding for the C-chain gene of human C1q. Approximately 600,000 recombinant phage plaques were hybridized with peroxidase-labeled human C-chain probe and detected by enhanced chemiluminescence. Five positive clones were obtained. The size of the full-length cDNA is 1019 bp. The sequence identity of the nucleotide sequence with human C1q C chain is 79%, the identity of the deduced amino acid sequences is 73%. The mouse C1q C chain exhibits the same structural features as the human C chain, e.g. conservation of the cysteine residues. Like the mouse A chain, the mouse C chain has an RGD sequence that may be recognized by receptors of the integrin family. No RGD sequences have been found in any of the human C1q chains. The size of the C-chain mRNA (1.2 kb) and its tissue distribution (macrophages being the cell type with the highest mRNA concentration) are identical to the mRNA of the mouse A and B chains. Alignment of human and mouse C1q A, B and C chains exhibits two blocks of highly conserved residues within the C-terminal globular regions. Three other proteins, collagen type VIII and type X and precerebellin share this similarity with C1q, indicating the structural and probably functional importance of these regions within the non-collagenous domains of the molecules.
Amino Acid Sequence↗
Gene expression of the A- and B-chain of mouse C1q in different tissues and the characterization of the recombinant A-chain.
Immunoscreening of a mouse macrophage cDNA library with an anti-mouse C1q-antibody resulted in the isolation of cDNA clones. The deduced amino acid sequence was homologous to the A-chain of human C1q. Homology on the DNA level was found to be 76% and on the protein level 72% thus it appeared the clones coded for the mouse C1q A-chain. An immunoblot of murine serum C1q separated by SDS-PAGE was detected with an A-chain specific antibody that had been affinity purified on recombinant mouse C1q A-chain expressed in Escherichia coli. The antibody preparation reacted exclusively with the mouse C-chain (as defined by SDS-PAGE). Northern blot analysis with strand-specific cDNA probes coding for the A- and B-chain of murine C1q showed that mouse peritoneal macrophages produced the highest concentration of C1q gene transcripts. RNA from mouse spleen, thymus, heart, and brain gave substantial hybridization signals, whereas RNA preparations from liver, kidney, lung, and small intestine appeared to contain only trace amounts of C1q mRNA. In a Northern blot analysis of different guinea pig cells and tissues, only RNA preparations from peritoneal macrophages hybridized with the mouse C1q probes. These results indicate that macrophages are a major site of C1q biosynthesis.
Amino Acid Sequence↗
Molecular cloning and characterization of the complementary DNA coding for the B-chain of murine Clq.
cDNA clones coding for the B-chain of murine Clq were isolated from a mouse macrophage library. The characterized clones include the total coding region plus a leader sequence. High homology was found with human Clq B-chain in the coding region (81%). Northern blot analysis of total RNA from different tissues of Balb/c mice showed one band of approximately 1.2 kb. The highest signal was found in RNA preparations of thioglycolate-activated peritoneal macrophages. The probe also hybridized with mRNA from spleen, thymus and heart. Extremely weak signals were found in liver, kidney, lung and intestine tissues.
Animals↗
The biosynthesis of C1q, the collagen-like and Fc-recognizing molecule of the complement system.
C1q, the collagen-like and Fc-recognizing component of the complement system, is mainly synthesized in macrophages and epithelial cells. Inhibitors of collagen biosynthesis, known to inhibit the post-translational hydroxylation of proline and lysine residues, were as effective in macrophages as inhibitors of C1q synthesis and secretion as has been described for collagen. This indicates that post-translational processing of C1q is dependent upon its collagen portions and triple helical formation within the cells. The macrophage-derived C1q is immuno- and physicochemically identical with serum C1q indicating that macrophages have to be considered as a major source for serum C1q. This was recently confirmed by Northern blot analysis using a cDNA probe for the B-chain of murine C1q. In contrast, an extremely weak signal was found in kidney, lung, gut, muscle and liver RNA. Besides the 11 S C1q molecule macrophages also synthesize a low molecular weight (LMW) form of C1q. The biological function of this 4 S LMW-C1q is still unclear. Macrophage-derived and secreted C1q is reinserted into the macrophage membrane. It is unlikely that the membranous form of C1q is bound via C1q-receptors into the membrane of macrophages since the B-chain of membrane-associated C1q is structurally different to that of fluid-phase C1q. The demonstration of a distinct membrane form of C1q supports earlier functional studies which implicated C1q as a membrane-associated molecule with receptor functions for those molecules which also interact with fluid-phase C1q, such as polyanions, the Fc portions of immune complexes, and bacteria (LPS and outer membrane proteins, OMP).
Animals↗
Cyclospora cayetanensis: first imported infections in Germany.
Over the last decade increasing numbers of enteritis cases have been attributed to infection with a new coccidian species that was named Cyclospora cayetanensis in 1993. Diarrhea caused by this agent is clinically indistinguishable from cryptosporidiosis, isosporiasis and microsporidiosis, but Cyclospora infections are often very prolonged (up to 15 weeks) and may cause severe weight loss. Diagnosis of infection is important because, in contrast to diarrhea caused by Cryptosporidium and microsporidia, treatment with co-trimoxazole is effective. Here we report the cases of two female patients, aged 70 and 58 years old, respectively, who suffered from severe, prolonged diarrhea after a vacation in Singapore, Java and Bali. Routine microbiological laboratory diagnostics were unable to demonstrate the presence of known enteropathogenic bacteria. Modified Ziehl-Neelsen staining of fecal smears revealed oocysts of Cyclospora cayetanensis, and treatment of the patients with co-trimoxazole was promptly effective. We would like to increase awareness of the possibility of Cyclospora infections in patients with prolonged diarrhea who have travelled to endemic areas.
Aged↗
Epidemiological study of Cryptosporidium parvum antibodies [corrected] in sera of persons from Germany.
In a seroprevalence study including 495 sera from persons of all age-groups, the presence of anti-Cryptosporidium parvum antibodies was evaluated in an enzyme immunoassay. Despite the fact that C. parvum is only found in approximately 2% of patients with diarrhea in Germany, specific antibodies could be detected in 15.4% of all samples. This figure indicates that a substantial proportion of the German population has been confronted with this parasite and it raises the question of whether C. parvum is a potential health risk to the general population.
Adolescent↗