Question

how do antibodies combat with antigen?

Answer 1

When antibodies bind to foreign antigens they perform a number of immune functions.

First, they activate the complement cascade. If the pathogen is cellular (bacterial) the complement can form a membrane attack complex which lyses the cell. Complement also attracts immune cells called phagocytes that ingest and destroy pathogens. Antibodies mark the pathogen for ingestion by phagocytes in a process known as opsonization.

In addition to phagocytes, antibodies bound to pathogens will also activate other immune cells such as mast cells, neutrophils, and natural killer cells. These cells either attack the pathogen or release chemicals that further activate elements of the immune system.

Lastly, antibodies that bind to pathogens can cause them to stick together (agglutinate). By coating the pathogens and causing agglutination, they can disable a pathogen or toxin.

Answer 2

Antibodies, also called immunoglobulins, are proteins manufactured by the body that help fight against foreign substances called antigens. When an antigen enters the body, it stimulates the immune system to produce antibodies. ... The antibodies attach, or bind, themselves to the antigen and inactivate it.