A characteristic of all IgGs is glycosylation in the CH2 domain at Asn297 [12], which is necessary for structure recognition and stability [13], and several effector functions, such as complement binding and activation, and interactions with Fc receptors [14] [18].
Activated microglia can wield several effector functions, such as phagocytosis, inflammatory responses and antigen presentation [ 32].
Neutrophils have several known effector functions against invading pathogens, including phagocytosis, release of antimicrobial molecules, production of reactive oxygen species (ROS), and release of neutrophil extracellular traps (NETs 12.
TCR engagement activates several CTL effector functions that contribute to antitumour immunity (Chavez-Galan et al, 2009).
We report the surprising finding that RF inhibits several RTX effector functions (complement dependent cytoxicity, FcR-mediated trogocytosis of CD19).
Findings from the few myeloid inhibitory receptors studied suggest, however, that these proteins are able to suppress several phagocyte effector functions, including phagocytosis, migration and cytokine production [ 7].
In the K/B×N transfer arthritis IgG1 antibodies against G6PI induce several different effector functions of the innate immune system; the alternative pathway of the complement cascade is triggered, resulting in chemotactic activity (but not the membrane attack complex) [ 70, 71].
However, in contrast to conventional Th cells, several NKT cell effector functions (such as cytotoxity and CXCR3 expression), which can be modulated in conventional T cells, were not responsive to polarizing cytokine signals or forced expression of TFs.
The inhibition by MICL of MSU-induced early signaling events is consistent with the known mode of action of inhibitory receptors and is strongly suggestive that MICL may regulate several MSU-induced neutrophil effector functions driven by downstream signaling events.
IgG antibodies, however, may co-engage the inhibitory FcγRIIb on several effector cell types, which can downregulate effector functions (Clynes et al, 2000; Hamaguchi et al, 2006; Minard-Colin et al, 2008).
Therefore, MSCs depend on a complex cross talk with several elements to inhibit the effector functions of T lymphocytes.
