Patients with multiple myeloma (MM) are at an increased risk for infections with bacteria that require opsonization with complement. Because Streptococcus pneumoniae is the most frequently encountered pathogen in these patients, we investigated the ability of serum from patients with MM to mediate the binding of C3b, the major opsonin of the complement system, to S. pneumoniae. S. pneumoniae ty...

The slow but spontaneous and ubiquitous formation of C3(H2O), the hydrolytic and conformationally rearranged product of C3, initiates antibody-independent activation of the complement system that is a key first line of antimicrobial defense. The structure of C3(H2O) has not been determined. Here we subjected C3(H2O) to quantitative cross-linking/mass spectrometry (QCLMS). This revealed details ...

Ethylene cross-bridged tetraamine macrocycles are useful chelators in coordination, catalytic, medicinal, and radiopharmaceutical chemistry. Springborg and co-workers developed trimethylene cross-bridged analogues, although their pendant-armed derivatives received little attention. We report here the synthesis of a bis-carboxymethyl pendant-armed cyclen with a trimethylene cross-bridge (C3B-DO2...

A receptor for fluid phase human complement (C) components C3 and C3b (1, 2) was found on the surface membranes of human lymphoblastoid cells. No other C proteins or serum factors were needed to mediate binding of C3 or C3b to this receptor. In studying its biological importance, we demonstrated that Raji cells cultured in medium containing fresh normal human serum (NHS) 1 and cobra venom facto...

T h e third c o m p o n e n t of complemen t (C) ~ has a central role in the activation of both the classical and al ternat ive pathways. C3 also has a variety o f di f ferent functions that are expressed e i ther a f ter C3 activation or dur ing the normal b reakdown o f the molecule. These functions of C3 are dependen t upon the exposure within C3 o f binding sites for o ther se rum proteins ...

Factor H (FH) is the major plasma regulator of the central complement protein C3b in the alternative pathway of complement activation. The elucidation of the FH interactions with five major ligands (below) is complicated by their weak μM dissociation constants K(D) and FH multivalency. We present the first survey of all the K(D) values for the major FH-ligand interactions and critically review ...

Alternative complement pathway C3 convertase formation involves the cleavage of C3b-associated factor B into fragments Ba and Bb. Whereas Bb, in complex with C3b, has proteolytic specificity toward native C3, the function of the Ba moiety in the formation and/or decay of alternative complement pathway C3 convertase is uncertain. Therefore, we have examined the effect of purified Ba fragment on ...

Component C3 is the central protein of the complement system. During complement activation, the thioester group in C3 is slowly hydrolysed to form C3u, then the presence of C3u enables the rapid conversion of C3 into functionally active C3b. C3u shows functional similarities to C3b. To clarify this mechanism, the self-association properties and solution structures of C3 and C3u were determined ...

IntroductionFHR1 is a member of Factor H (FH) protein family involved in complement to regulate the innate immune response. FHR1 shares with FH highly conserved C-terminal region and considered act as competitor cause induction. also an inflammatory mediator able inhibit terminal activation. Homozygous deletion FHR1, found occur 10% healthy population, strongly associated pathologies like atypi...

Glycoprotein C (gC) from herpes simplex virus (HSV) facilitates virus entry by attaching the virion to host cell-surface heparan sulfate (HS). Although gC from HSV-1 (gC1) and from HSV-2 (gC2) bind to heparin, gC2 is believed to play a less significant role than gC1 in attachment of virus to cells. This attachment step is followed by the binding of gD to one of several cellular receptors. gC al...