Biophysical Immunology Laboratory Thomas Vorup-Jensen Institute for Medical Microbiology and...

Biophysical Immunology Laboratory

Thomas Vorup-JensenInstitute for Medical Microbiology and

ImmunologyUniversity of Aarhus

[email protected]

Innate ImmunityJaneway’s Immunobiology Chapter 2&3

Lecture II:(mainly) Soluble (humoral) factors

Important messages:

Important soluble molecules supporting innate immunity effectorfunctions

Connection between molecular structure and function in the immuneSystem

Connection between cellular and humoral innate immunity

2

The (very) basic order of events in complement activation:three steps to inflammation

Complement factors insolution (plasma) Surface bound

complement factors

Pathogen

Cascade deposition:positive amplificationloop

Conformationalchange?

Recruitment of inflammatory cells

EnhancedPhagocytosis

(faster clearing!)

Direct killingby lysis

3

”Target-binding” complement proteins are larger than the rest….

Vorup-Jensen & Boesen (2011) Adv. Drug Discov. Rev. 63:1008-19

35 nm

…but why?

Tanaka et al. (2010)

J Infect Chemother 16:383–387



Important messages:

The classical pathway is activated through antibodies:Major molecular species involved are C1, C2 and C4 supportingto C3 activation

13



Important messages:

The alternative pathway is activated spontaneous depostion of C3on cell surface. Failure to down-regulate C3 activation leads toopsonization of microbes.

19

Dong et al. J. Immunol. (2007) 178:3016-22

SAXS solution structure of MBL

Trimer of carbohydrate-recognitiondomains

23

Atomic Force Microscopy

Mingdong Dong, Sailong Xu & Flemming BesenbacheriNANO, University of Aarhus

24

Constructing a MBL ligand-coated surface suitable for AFM

Mannose-amine immobilized on mica through coordination bonds

NH3

O

NH3

O

NH3

O

SiO3-

Min

eral

(m

ica)

str

uctu

re

25

AFM imaging of rhMBL(I) on a mannosamine-coated surfacein liquid

Dong et al. J. Immunol. (2007) 178:3016-2226

BSA BSA BSA

BSA BSA BSA

BSA

BSA

BSASI = 600 RU

SI = 1600 RU

SI = 4000 RU

1,000 RU 1 ng protein/mm2

0.005 mcBSA molecules/mm2



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Surface density of ligandschange MBL bindingkinetics

60 nm

KD 10-10 M and kd 10-6 s-1

d ~ 14 nm

d ~ 9 nm

d ~ 6 nm

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Organization of the cell wall of S. aureus: a nm-scaled pattern?

Touhami A et al. (2004) J. Bacteriol. 186: 3286–3295.

50 nm

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Primary immunodeficiencyin the innate immune system

Induced deficiencyin neutrophils

31



Important messages:

The lytic pathway may serve to from pores in target membranes. Thepore formation will eventually leads to cellular lysis.

35

Time

(adaptive immunity)39



Important messages:

The complement system is an important mediator of cross-talk betweeninnate and adaptive immunity by mediating antigen uptake.

41

iC3b is ”inactive” with regard to C3 conversion but may bindComplement receptors 3 & 4

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Hereditary angioedema: lack of C1INH

Treatment: blood transfusion or C1INH protein

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48

Systemic Lupus Erythematosus (SLE)

trialx.com



Important messages:

Failure to control complement activation leads to significanthealth problems

49


Lectures I & II

Important messages:

Important soluble molecules supporting innate immunity effectorFunctions

Cytokines & complement

Connection between molecular structure and function in the immunesystem

Pattern recognition, conformational changes in MBL

Connection between cellular and humoral innate immunityOpsonization facilitates antigen presentation to lymphocytes

50

Biophysical Immunology Laboratory Thomas Vorup-Jensen Institute for Medical Microbiology and...

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