Immune Responses

When B cells or T cells become activated after first encountering the antigens for which they are specialized to react, their actions constitute a primary immune response. During such a response, plasma cells release antibodies (IgM, followed by IgG) into the lymph (fig. 16.22). The antibodies are transported to the blood and then throughout the body, where they help destroy antigen-bearing agents. Production and release of antibodies continues for several weeks.

Following a primary immune response, some of the B cells produced during proliferation of the clone remain dormant and serve as memory cells (fig. 16.22). If the identical antigen is encountered in the future, the clones of these memory cells enlarge, and they can respond rapidly with IgG to the antigen to which they were previously sensitized. These memory B cells along with the previously discussed memory T cells produce a secondary immune response. Cells in lymph nodes called follicular dendritic cells may help memory by harboring and

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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