Innate immunity refers to the non-specific defense mechanisms that an individual is born with. It works by providing various types of barriers to prevent foreign agents from entering the body. Unlike acquired immunity, innate immunity is not specific to particular pathogens and does not involve memory cells that recognize previous infections.

In contrast, acquired immunity is specific to certain pathogens and involves memory cells that help recognize and respond more efficiently to repeated infections by the same pathogen. The immune response mediated by B-lymphocytes is known as humoral immunity, while the response mediated by T-lymphocytes is termed cell-mediated immunity.