Final answer:
The biological effector function of antibodies depends on factors such as affinity, avidity, and cross-reactivity. Antibodies bind to antigens, act as receptors, and circulate to label pathogens for identification. They can also trigger antibody-dependent cell-mediated cytotoxicity to enhance pathogen killing.
Step-by-step explanation:
The biological effector function of antibodies depends on several factors, including their affinity, avidity, and cross-reactivity. Antibodies with a higher affinity for a specific antigen bind more strongly and stably, allowing them to present a more effective defense against the corresponding pathogen. Additionally, antibodies can act as B cell antigen receptors or be secreted to bind and label pathogens for identification by other parts of the immune response. They can also trigger antibody-dependent cell-mediated cytotoxicity (ADCC) to enhance the killing of larger pathogens.