Immunity may be passive or active. During passive immunity, antibodies made in another person or animal enter the body and the immunity is short-lived and Active Immunity: In the case of active immunity, antigens enter the body and the body responds by making its own antibodies and B-memory cells. In this case, immunity is longer lived although duration depends on the persistence of the antigen and the memory cells in the body. Both passive and active immunity can be either naturally or artificially acquired.
Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS)