List and describe 4 ways antibodies aid in immunity?

1. Antibody neutralization: Antibodies can prevent pathogens from infecting cells by binding to them and blocking their entry. For example, antibodies against the spike protein of SARS-CoV-2 can prevent the virus from binding to ACE2 receptors on human cells, thereby preventing infection.

2. Opsonization: Antibodies can bind to pathogens and make them more visible to immune cells, such as macrophages and neutrophils. This process is called opsonization. Opsonized pathogens are more likely to be phagocytized and killed by immune cells.

3. Complement activation: Some antibodies can activate the complement system, which is a group of proteins that work together to kill pathogens. Complement activation can lead to the formation of pores in the pathogen's cell membrane, causing cell death.

4. Antibody-dependent cell-mediated cytotoxicity (ADCC): ADCC is a mechanism by which antibodies can trigger the killing of infected cells by immune cells, such as natural killer (NK) cells and monocytes. Antibodies bind to antigens on the infected cell, and then the immune cells bind to the antibodies and release cytotoxic molecules that kill the infected cell.

These are just four of the ways antibodies aid in immunity. They are essential components of the immune system and play a vital role in protecting the body against infection.