14.2: Specific Adaptive Host Defenses
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- 14.2.3: T Lymphocytes
- The antibodies involved in humoral immunity often bind pathogens and toxins before they can attach to and invade host cells. Thus, humoral immunity is primarily concerned with fighting pathogens in extracellular spaces. However, pathogens that have already gained entry to host cells are largely protected from the humoral antibody-mediated defenses. Cellular immunity, on the other hand, targets and eliminates intracellular pathogens through the actions of T lymphocytes, or T cells.
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- 14.2.5: Vaccines
- By artificially stimulating the adaptive immune defenses, a vaccine triggers memory cell production similar to that which would occur during a primary response. In so doing, the patient is able to mount a strong secondary response upon exposure to the pathogen—but without having to first suffer through an initial infection. In this section, we will explore several different kinds of artificial immunity along with various types of vaccines and the mechanisms that they induce artificial immunity.
Thumbnail: From left to right: erythrocyte ,platelet and lymphocyte. (Public Domain; The National Cancer Institute at Frederick ).