Palivizumab 100mg powder and solvent for solution for injection vials

Receptor for the invariable Fc fragment of immunoglobulin gamma (IgG). Optimally activated upon binding of clustered antigen-IgG complexes displayed on cell surfaces, triggers lysis of antibody-coated cells, a process known as antibody-dependent cellular cytotoxicity (ADCC). Does not bind free monomeric IgG, thus avoiding inappropriate effector cell activation in the absence of antigenic trigger .
PMID:11711607 PMID:21768335 PMID:22023369 PMID:24412922 PMID:25786175 PMID:25816339 PMID:28652325 PMID:8609432 PMID:9242542

Mediates IgG effector functions on natural killer (NK) cells.

Binds antigen-IgG complexes generated upon infection and triggers NK cell-dependent cytokine production and degranulation to limit viral load and propagation. Involved in the generation of memory-like adaptive NK cells capable to produce high amounts of IFNG and to efficiently eliminate virus-infected cells via ADCC .
PMID:24412922 PMID:25786175
Regulates NK cell survival and proliferation, in particular by preventing NK cell progenitor apoptosis .
PMID:29967280 PMID:9916693
Fc-binding subunit that associates with CD247 and/or FCER1G adapters to form functional signaling complexes. Following the engagement of antigen-IgG complexes, triggers phosphorylation of immunoreceptor tyrosine-based activation motif (ITAM)-containing adapters with subsequent activation of phosphatidylinositol 3-kinase signaling and sustained elevation of intracellular calcium that ultimately drive NK cell activation.

The ITAM-dependent signaling coupled to receptor phosphorylation by PKC mediates robust intracellular calcium flux that leads to production of pro-inflammatory cytokines, whereas in the absence of receptor phosphorylation it mainly activates phosphatidylinositol 3-kinase signaling leading to cell degranulation .
PMID:1825220 PMID:23024279 PMID:2532305

Costimulates NK cells and trigger lysis of target cells independently of IgG binding .
PMID:10318937 PMID:23006327
Mediates the antitumor activities of therapeutic antibodies. Upon ligation on monocytes triggers TNFA-dependent ADCC of IgG-coated tumor cells .
PMID:27670158
Mediates enhanced ADCC in response to afucosylated IgGs PMID:34485821

Serine protease component of the complement C1 complex, a multiprotein complex that initiates the classical pathway of the complement system, a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system .
PMID:17996945 PMID:19473974 PMID:29449492

C1R catalyzes the first enzymatic step in the classical complement pathway: it is activated by the C1Q subcomplex of the C1 complex, which associates with IgG or IgM immunoglobulins complexed with antigens to form antigen-antibody complexes on the surface of pathogens .
PMID:29449492 PMID:34155115
Immunoglobulin-binding promotes the autocatalytic cleavage and activation of C1R .
PMID:11445589 PMID:11673533 PMID:17996945 PMID:20178990 PMID:6254570 PMID:6271784

Activated C1R then cleaves and activates C1S, the second protease of the classical complement pathway .
PMID:11445589 PMID:11673533 PMID:6271784

It is unclear if C1R activates C1S within single, strained C1 complexes or between neighboring C1 complexes on surfaces PMID:28104818 PMID:29311313 PMID:29449492

Core component of the complement C1 complex, a multiprotein complex that initiates the classical pathway of the complement system, a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system .
PMID:12847249 PMID:19006321 PMID:24626930 PMID:29449492 PMID:3258649 PMID:34155115 PMID:6249812 PMID:6776418

The classical complement pathway is initiated by the C1Q subcomplex of the C1 complex, which specifically binds IgG or IgM immunoglobulins complexed with antigens, forming antigen-antibody complexes on the surface of pathogens: C1QA, together with C1QB and C1QC, specifically recognizes and binds the Fc regions of IgG or IgM via its C1q domain .
PMID:12847249 PMID:19006321 PMID:24626930 PMID:29449492 PMID:3258649 PMID:6776418

Immunoglobulin-binding activates the proenzyme C1R, which cleaves C1S, initiating the proteolytic cascade of the complement system .
PMID:29449492
The C1Q subcomplex is activated by a hexamer of IgG complexed with antigens, while it is activated by a pentameric IgM .
PMID:19706439 PMID:24626930 PMID:29449492

The C1Q subcomplex also recognizes and binds phosphatidylserine exposed on the surface of cells undergoing programmed cell death, possibly promoting activation of the complement system PMID:18250442