The complement system is an innate immune defense machinery comprising components that deploy rapid immune responses and provide efficient protection against foreign invaders and unwanted host elements. The complement system is activated upon recognition of pathogenic microorganisms or altered self-cells by exclusive pattern recognition molecules (PRMs), such as collectins, ficolins and pentraxins. Recent accumulating evidence shows that the different classes of effector PRMs build up a co-operative network and exert synergistic effects on complement activation. In this review, we describe our updated view of the crosstalk between previously unlinked PRMs in complement activation and the potential pathogenic effects during infection and inflammation.
Collectins ; Complement Activation* ; Complement System Proteins* ; Inflammation

BACKGROUND AND OBJECTIVES: Surfactant protein-A (SP-A) is a member of the collectin family, and plays an important role in the first-line airway defense. The purpose of study was to examine the expression of SP-A mRNA and protein in human salivary glands, and to investigate its up-regulation during inflammatory conditions of salivary glands. MATERIALS AND METHOD: Reverse transcription-polymerase chain reaction was performed on salivary gland tissues from ten patients with chronic sialadenitis and ten samples of normal salivary gland tissue. The expression levels of SP-A to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) transcripts were semi-quantified by densitometry. We also characterized the cellular localizations of SP-A protein immunohistochemically. RESULTS: SP-A mRNA and protein were detected in normal and chronic sialadenitis glands. The expression levels of SP-A mRNA in salivary glands with chronic sialadenitis was significantly increased as compared with normal salivary glands. Immunohistochemical staining revealed SP-A immunoreactivity in the ductal epithelia of normal salivary glands and chronic sialadenitis, and stronger immunoreactivity was observed in chronic sialadenitis tissues. CONCLUSION: SP-A is present in the human salivary gland epithelium and is up-regulated during chronic sialadenitis. These results suggest that salivary gland SP-A may play an important role in the innate host defense of human salivary glands.
Collectins ; Densitometry ; Epithelium ; Humans ; Pulmonary Surfactant-Associated Protein A ; RNA, Messenger ; Salivary Glands ; Sialadenitis* ; Up-Regulation*

The grass carp (Ctenopharyngodon idella) collectin gene was cloned from mixed liver and kidney cDNA library. The full length sequence of grass carp collectin was 1128 bp, contained a 5' untranslated region of 229 bp and a 3' untranslated region of 104 bp. The open reading frame of grass carp collectin was 795 bp which could code a 264 amino acids polypeptide, including a terminal codon. Phylogenetic analyses showed that grass carp collectin shared the highest homology with that of zebrafish (Danio rerio). To understand the function of grass carp collectin, we expressed and purified the recombinant protein (P(CRD)) that comprised carbohydrate recognition domain (CRD). Agglutination of Aeromonas hydrophila and Staphylococcus aureus etc. and sugars inhibition experiments showed that: galactose, glucose, mannose and maltose could inhibit the agglutination of Aeromonas hydrophila. Maltose could lower the agglutination of Staphylococcus aureus, whereas peptidoglycan and glucose inhibited it well. In addition, the activity of grass carp collectin could not dependent on Ca(2+).
Amino Acid Sequence ; Animals ; Base Sequence ; Carps ; genetics ; Cloning, Molecular ; Collectins ; genetics ; physiology ; Fish Proteins ; genetics ; physiology ; Molecular Sequence Data ; Phylogeny ; Zebrafish ; genetics

OBJECTIVETo investigate the relationship between codon 54 gene polymorphism of the host defense molecule, mannose-binding protein (MBP), and the patterns of glomerular immune deposition in IgA nephropathy (IgAN).

METHODSIgAN patients with different patterns of glomerular immune deposition were selected and divided into two groups. Group A consisted of 77 patients with glomerular IgA and C3 deposits, and Group AGM consisted of 70 patients with glomerular IgA, IgG, IgM, C3 and Clq deposits. Clinical features and laboratory relevant data of all patients were collected. One-hundred and forty healthy adults were recruited as normal controls. The MBP gene codon 54 GGC/GAC polymorphism was investigated by using polymerase chain reaction and restriction fragment length polymorphism.

RESULTSThe genotype frequency of GGC/GAC heterozygotes was significantly higher in Group AGM as compared with that of Group A (41.4% vs 19.5%, P < 0.01) or normal subjects (41.4% vs. 26.4%, P < 0.05), while no difference was found in the distribution of MBP genotypes between Group A and normal subjects. GAC allele frequency was also higher in Group AGM than that in Group A (0.24 vs. 0.14, P < 0.05) or normal subjects (0.24 vs. 0.15, P < 0.05). The variant allele (GAC) was markedly associated with Group AGM (OR = 1.95, 95% CI: 1.06 - 3.58). In both Group A and Group AGM, more patients carrying the variant allele had episodes of upper respiratory or gastrointestinal infections prior to the onset of IgAN than those with wild homozygotes (GGC/GGC).

CONCLUSIONSGenetic variation of the host defense molecule, MBP, may be involved in the formation of the diverse patterns of glomerular immune deposition in IgAN. The variant allele of the MBP gene may partially account for abundant immune deposits in some IgAN patients.

Adult ; Alleles ; Carrier Proteins ; genetics ; Collectins ; DNA ; genetics ; Female ; Gene Frequency ; Genetic Variation ; Genotype ; Glomerulonephritis, IGA ; genetics ; immunology ; Humans ; Kidney Glomerulus ; immunology ; pathology ; Male ; Polymorphism, Restriction Fragment Length

Endometritis is one of the primary reasons for reproductive failure. In order to investigate endometritis-associated marker proteins, proteomic analysis was performed on bovine endometrium with endometritis. In bovine endometritis, desmin, alpha-actin-2, heat-shock protein (HSP) 27, peroxiredoxin-6, luteinizing hormone receptor isoform 1, collectin-43 precursor, deoxyribonuclease-I (DNase-I), and MHC class I heavy chain (MHC-Ih) were up-regulated. In contrast, transferrin, interleukin-2 precursor, hemoglobin beta subunit, and potassium channel tetramerisation domain-containing 11 (KCTD11) were down-regulated in comparison to normal endometrium. The proteomic results were validated by semiquantitative-PCR and immunoblot analysis. The mRNA levels of desmin, transferrin, alpha-actin-2, HSP27, KCTD11, and MHC-Ih were up-regulated by over 1.5-fold, and showed a pattern similar to their proteomic profiles. Desmin and alpha-actin-2 protein showed positive correlations between proteomic analysis and immunoblot analysis. These results suggest that desmin and alpha-actin-2 may play important roles in endometritis-related function, and could be useful markers for the diagnosis of bovine endometritis.
Actins ; Collectins ; Desmin ; Endometritis ; Endometrium ; Female ; Heat-Shock Proteins ; Hemoglobins ; Interleukin-2 ; Potassium Channels ; Proteins ; Proteomics ; Receptors, LH ; RNA, Messenger ; Transferrin

PURPOSE: Collectin family is an important component of innate immunity, of which surfactant protein (SP)-D and mannose-binding lectin (MBL) are the most characterized. We examined SP-D and MBL in young children with acute respiratory syncytial virus (RSV) bronchiolitis. METHODS: Sixty-three children (< or =24 months of age) admitted with the first RSV bronchiolitis during 2 epidemics and followed for 1 year after discharge were enrolled. The patients were defined as severe group when they had 2 of followings during admission: hypoxemia (<92% oxygen saturation), rapid breathing (and/or lower chest wall indrawing), and >7 days of hospital stay. All children were evaluated if they had recurrent wheezing during follow-up. SP-D and MBL were measured using enzyme-linked immunosorbent assay in serum collected on admission and compared with controls. Their levels were evaluated in relation to the symptom severity during admission and recurrence of wheezing after discharge. RESULTS: Serum SP-D increased significantly in the patients (P<0.01), but MBL showed no difference compared to the controls. SP-D levels were significantly higher in severe group compared with nonsevere group (P<0.05). SP-D levels in the patients with recurrent wheezing after discharge were significantly higher than in those without (P<0.05). MBL showed no difference in relation to the symptom severity or recurrence of wheezing. CONCLUSION: Our study showed that serum SP-D was associated with the severity of RSV bronchiolitis and suggests that it might be a biomarker of lung injury and recurrence of wheezing illnesses in the young children admitted with their first RSV bronchiolitis.
Anoxia ; Bronchiolitis ; Child ; Collectins ; Enzyme-Linked Immunosorbent Assay ; Follow-Up Studies ; Humans ; Immunity, Innate ; Infant ; Length of Stay ; Lung Injury ; Mannose-Binding Lectin ; Oxygen ; Pulmonary Surfactant-Associated Protein D ; Recurrence ; Respiration ; Respiratory Sounds ; Respiratory Syncytial Viruses ; Thoracic Wall

BACKGROUND AND OBJECTIVES: Collectins (surfactant protein A and D) are proteins with collagen tails and globular lectin domains that appear to play an important role in the first line of host defense in mammalians. However, it is not known if collectins are also present in human nasal mucosa. The purpose of this study was to investigate the expression of collectin proteins in human nasal mucosa and to compare the expressions of SP-A and D mRNA in the normal nasal mucosa and in chronic inflammatory nasal diseases. MATERIALS AND METHOD: Ten chronic rhinosinusitis patients were recruited and ten normal nasal mucosae were used as normal controls. Reverse transcriptase-polymerase chain reaction was performed to detect SP-A and SP-D mRNA. The level of collectin and GAPDH (glyceraldehyde-3-phosphate dehydrogenase) transcripts were semi-quantified with the desitometry. We have characterized the cellular localization of SP-A and SP-D protein using immunohistochemistry. RESULTS: SP-A2/GAPDH mRNA ratio in chronic rhinitis nasal mucosa is greater compared with that in normal nasal mucosa (p<0.05). SP-A protein was expressed in the nasal epithelium and in the epithelial cells of the submucosal glands. SP-D mRNA and protein were not expressed in the nasal mucosa. CONCLUSION: These data provide the first evidence of the presence of collectins in the human nasal mucosa. These results suggested that up-regulation of collectin in chronic rhinosinusitis may be a protective response for the nasal mucosa.
Collagen ; Collectins* ; Epithelial Cells ; Humans* ; Immunohistochemistry ; Nasal Mucosa* ; Nose Diseases ; Pulmonary Surfactant-Associated Protein A ; Pulmonary Surfactant-Associated Protein D ; Pulmonary Surfactants ; Rhinitis ; RNA, Messenger ; Sinusitis ; Staphylococcal Protein A ; Up-Regulation

Conglutinin is a high molecular-weight lectin originally detected in bovine serum. It belongs to the family of collectins that bind sugar residues in a Ca(2+)-dependent manner and are effector molecules in innate immunity. Conglutinin appears to play an important role in immune defense mechanisms, showing antiviral and antibacterial activities when tested in vivo and in vitro. The present study evaluated the effect of conglutinin on the respiratory bursts in bovine peripheral phagocytes. Using nitroblue tetrazolium and hydrogen peroxide assays, we showed that sugar ligand-bound conglutinin stimulated the production of superoxide and H2O2 in granulocytes whereas the non-sugar-bound form of conglutinin inhibited these processes. These results indicate that both forms of conglutinin are able to interact with surface leukocyte receptors but have opposite effects on phagocytic activity. Our findings suggest that conglutinin bound to sugar residues on microbial surfaces can induce oxygen burst in phagocytes, and thereby mediates the elimination of pathogens and prevents the spread of infection.
Animals ; Cattle/*immunology ; Collectins/*pharmacology ; Enzyme-Linked Immunosorbent Assay/veterinary ; Female ; Granulocytes/*drug effects/immunology ; Hydrogen Peroxide/immunology ; Immunity, Innate/drug effects/immunology ; Phagocytosis/immunology ; Reactive Oxygen Species/*immunology ; Respiratory Burst/*drug effects/immunology ; Serum Globulins/*pharmacology ; Statistics, Nonparametric ; Superoxides/immunology