Final answer:
IgG1 and IgG3 can recruit phagocytic cells like macrophages and neutrophils to ingest pathogens. This is due to opsonization, where IgG antibodies coat pathogens, enhancing phagocyte binding and facilitating the destruction of the pathogen. Complement fixation further increases this process.
Step-by-step explanation:
Once bound to antigen, IgG1 and IgG3 can directly recruit phagocytic cells to ingest pathogens.
Antibodies, such as IgG1 and IgG3, play a crucial role in the immune system's ability to clear infections. They do so by marking pathogens for destruction through a process known as opsonization. This involves the coating of pathogens with antibodies that enhance the ability of phagocytes to bind and engulf the pathogens. These phagocytic cells, such as macrophages and neutrophils, have receptors that specifically bind to the Fc portion of the IgG molecules. This interaction facilitates the attachment of the phagocyte to the pathogen, leading to its ingestion and destruction.
The binding of IgG antibodies to pathogens also triggers other immune responses such as complement fixation, which further amplifies the opsonization process. Complement proteins bind to the antibodies that have attached to antigens, which enhances the clearance of these pathogens from the body.