L01_02 Innate v. Acquired Immunity

Innate & Acquired Immunity

Innate ImmunityPresent since birth (i.e. constitutive), this type of immunity is the first line of defense against foreign substances. As it is not antigen-specific its attack is the same without regards to what type of antigen is present. This also indicates the lack of "memory" of innate immunity.

Acquired Immunity Acquired immunity is not necessarily present at birth, rather it matures later in life due to its "memory" characteristic. Since it is antigen-specific, the "memory" allows for greater response against the same antigen if it were present in the body again. It must be induced for a response to occur. Includes Active and Passive immunity Active immunity involves the individual making his/her own immune products Passive immunity involves giving immune products to an individual (i.e. vaccination, antidote) Active immunity is split into Humoral and Cell Mediated Immunity Humoral Immunity contains B cells which produce antibodies against extracellular bacteria and toxins Cell Mediated Immunity contains T cells which produce cytokines against intracellular bacteria, viral infections, and cancer cells.

Steps Healthy individual, go to (2.) OR (7.) Foreign substance (FS) detected by immune system Innate immunity kicks in and attacks the FS. Recovers, go to (1.) OR FS is too much to handle, go to( 5.) FS level reaches threshold and induces an Acquired Immune Response FS is eliminated and the Acquired Immunity "remembers" its offensive/defensive tactics for the next time the same FS comes, go to (1.) FS returns, go to (5.) but with a stronger response by Acquired Immunity