It develops in the blood. The lymphocytes from various globulin proteins to destroy the different antigens.
These lymphocytes are formed from the mesodermal stem cells but some lymphocytes are also formed in the thymus gland & bone marrow.
In humoral immunity when an antigen! bacteria/virus enters into the body, the lymphocytes in lymphatic organs divide rapidly and convert into plasma cells to form required antibodies.
It protects the body from tetanus, cold, smallpox, measles, cholera etc.