Immune response

The immune response is a defensive or protective reaction against foreign substances called antigens. There are two types of immune responses: nonspecific and specific.

Nonspecific Immune Response

The nonspecific response occurs against many antigens. For example, phagocytosis is a nonspecific immune reaction.

Specific Immune Response

The specific response targets a specific antigen. During this process, lymphocytes secrete immunoglobulins called antibodies into the blood, lymph, and mucus. These antibodies circulate, specifically recognize, and destroy the antigen. Mammalian bone marrow and the bursa of Fabricius in birds form lymphocytes. B cells attach surface immunoglobulins to their membrane.

Types of Immune Response

Depending on the mechanisms that remove the antigen, the specific immune response is classified as either humoral or cellular. Both immune responses involve various white blood cells, including lymphocytes, neutrophils, eosinophils, basophils, and monocytes, as well as tissue macrophages, dendritic and mast cells, and platelets.

Humoral Immune Responses

In humoral immune responses, antibodies participate as circulating molecules in the blood. These antibodies can destroy the antigen and can be transferred with blood plasma or serum. B lymphocytes, responding to the antigen, transform into antibody-producing cells that trigger humoral immune responses.

Cellular Immune Responses

In cellular immunity, specific lymphocytes recognize and eliminate the antigen. T lymphocytes induce cellular immune responses. Two different groups of lymphocytes are involved in humoral and cellular immune responses: T and B lymphocytes.

By understanding these different components and mechanisms, we can better grasp how the immune system defends the body against various threats.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė