Innate immunity. Peter Garred. MBL mangel og dets betydning ved lungesygdom. MBL Ficolin-1, -2 and -3 Functions of MBL. MBL attack

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1 Innate immunity Peter Garred mangel og dets betydning ved lungesygdom Pathogen-Associated Molecular Patterns -liposaccharides -glucans -bacterial DNA -viral dsdna Pattern recognition receptors -cell bound (TLRs) -intracellular (NOD/CARD) -soluble DNA acteria Ficolins and Phagocytic cell Ficolins Ficolin-, -2 and -3 Functions of CRD domain Collagen-like domain FG domain Neck region Cysteine rich region Linker region receptor? Normal cell Phagocytosis Phagocyte Complement activation Dying cell Interaction with ligands complement activation via associated serine proteases (MASPs) Clearance of Cellular debris attack Sir Frances Mcfarlane urnet, MASPs C4,C2 C3 -MASPs, 2, 3 C5a C9 C4bC2b C3b C3b C5b-8 Microorganism Membrane attack complex Nobel Laureate in 96 in medicine Probably discovered in 946 as β-inhibitor of influenza virus

2 Mannose-binding lectin history 968: deficiency of serum activity phagocytosis was observed in a little girl suffering from recurrent infections Mannose-bindinding lectin () history 978 Japanese scientists discovers in rabbit liver 987 Japanese scientists discovers that is a part of the complement system 989 English og Danish scientists discovers that the serum deficiency was caused by deficiency 989 English og American scientists clone the gene (2) 99 English scientists discovers a mutation in the 2 gene causing deficiency 992 Japanese scientists discovers the lectin pathway of complement activation 2 gene 5 Ex Ex Ex2 Ex3 Ex4 3 Promoter Promoter Three SNPs present on different 2 haplotypes result in low levels of functional serum N-terminal cysteines 25 Kd polypeptide Collagen-like domain Coiled coil neck region C-type CRD domain Mutation tetramer Codon: Name: Arg Cys Gly Asp Gly Glu D C 2 structural gene variations serum Koncentration (µg/l) A= normal type = glycine til aspartic acid 54 C= glycine til glutamic acid 57 D= arginine til cysteine 52 Promoter region and exon of the 2 gene GC box TATA box GRE HSE CCAAT box transcription start UT exon Denmark A/A A/ A/C A/D /+D/D+/D etc 6% 23% 4% 8% 5% 994 Allele: (position) H/L X/Y (- 55) (- 22) DC (codons 52,54,57) 2

3 5 A/A genotype 4 A/O genotype, O =, C or D koncentration (µg/l) koncentration (µg/l) Danes HY/HY LY/LY LX/LX HY/LY HY/LX LY/LX 995 HY LY LX Danes 995 Variant ELISA Gel filtration (Superdex 2) of sera with different 2 genotypes and subsequent testing for reactivity in ELISA OD 49 nm A/A 25 Kd oligomers - 6 OD 49 nm A/ / 5 Kd Kd 75 Kd 5 Kd OD 49 nm Kd YA/XA XA/XA XA/D YA/ /D D/D 2,5 5 7, , , ,5 Fr a c tio n s MW, 3 kd, 667 kd, 443 kd, 2 kd, 5 kd, 67 kd 23 Unreduced Reduced 23 Period of vulnerability hypothesis of function Normal level Clinical importance? Maternal IgG abs Child s IgG abs Age (months)

4 Ante-antibody hypothesis of function Primary response Secondary response Lag phase Acute Respiratory Tract Infections and Insufficiency During Early Childhood, the Greenland Study concentration Antibody concentration Sisimiut Antigen first time Antigen Days second time 989 Anders Koch et al, JAMA 2l Cumulative risk of acute respiratory tract infections by 2 genotypes in 252 children followed prospectively for 2 years relative risk 3 2,92 Common Variable Immunodeficiency CVID 2,5 2,5,5 P<.,47 A/A+YA/ XA/+/ Heterogeneous group of immunological disorders, unknown etiology, levels of serum immunoglobulins and impaired antibody responses Sisimiut, West-Greenland -5 months 6-7 months 8-24 months Anders Koch et al, JAMA 2l Pneumonia up to 2 years pre-diagnostic in CVID patients by somatic hypermutation and 2 variant alleles Mutated fraction (%) No pneumonia A/A genotype 2 pneumonia per year A/O+O/O genotypes 2 > pneumonia per year P<. Andersen et al., lood 25 Low Serum Mannose-inding Lectin Level Increases the Risk of Death due to Pneumococcal Infection Forest plot of association between mannose-binding lectin() deficiency ( level,.5 microgram/ml) and death Diamond Eisen et al., Clin. Infect. Dis. 28 4

5 Cystic fibrosis (CF) is the most common severe inherited disease among Caucasians There are about 4 CF patients in Danmark Life expectancy is about 4 years Clinical symptoms of CF Salty taste of the skin Failure to grow ulky and greasy stool (steatorrhea) Thick sputum Coughing or wheezing Frequent recurring pneumonia (spec. P. aeruginosa) The symptoms may differ with varying degree of severity and with varying prognosis Question: Are there genetic factors that may modify the course of the disease? Survival probability CF patients: annual age-specific mortality rate by 2 variant alleles A/+/ A/A Years P= time-to-event analysis showing median age with first positive P. aeruginosa bacterial culture in 393 Canadian CF patients TGF TT genotype TGF CT genotype TGF CC genotype 2 time-to-event analysis (as in last figure) plots show 3 2 genotype groups and stratifcation by TGF genotype Dorfman et al., JCI 28 Dorfman et al., JCI 28 Loss of lung function ( FEV) from 6 to 8 years dependent on 2 and TGF CC genotypes Impact of mannose binding lectin () insufficiency on the course of cystic fibrosis: a review and meta-analysis High Intermediate P<.2 Low 6 8 years James D. Chalmer et al, Glycobiology 2 5

6 Distribution of structural 2 variant alleles /, 65%,C,D A/A, 7% A/, 28% C C,,D A Wildtype Heterozygote Homozygote variant Quechua people Positive Selection for 2 Variant Alleles The high frequency of variant alleles and the dominant effect on the functional level suggests a selective advantage for heterozygotes (A/O) (heterosis) Hypothesis : heterozygosity for 2 variant alleles protect against intracellular microorganisms Risk U-formed risk curve favouring heterozygosity Low Intermediate High Hypothesis 2: heterozygosity for 2 variant alleles protect against deleterious effect of complement activation None of these theories are mutually exclusive 992 serum concentration Summary plays an important role as disease modifier in individuals with a concomitant disease Screening for 2 alleles and serum levels may be of prognostic importance in conjunction with other parameters 6