In the case of type II hypersensitivity, which antibodies are primarily involved?

Type II hypersensitivity reactions involve the immune system's response to antigens that are present on the surface of cells. In this type of hypersensitivity, antibodies, specifically IgG and IgM, play a central role.

When these antibodies bind to the antigens on cell surfaces, they activate the complement system and promote inflammatory responses that can lead to cell destruction or damage. This mechanism is commonly seen in conditions like autoimmune hemolytic anemia and transfusion reactions, where the body mistakenly targets its own cells or reacts against foreign cells due to mismatched blood types.

The other types of antibodies mentioned, such as IgA and IgE, are associated with different immune functions. IgA plays a crucial role in mucosal immunity, while IgE is primarily involved in allergic reactions and responses to parasitic infections. Therefore, while these antibodies have important roles in the immune system, they are not directly involved in the mechanism of type II hypersensitivity.