Course # DL-981: An Overview of the Immune System, Part Two: The Generation & Evaluation of Immune Responses
by Elizabeth Crabb Breen, M.T. (ASCP), Ph.D. – Associate Professor – Norman Cousins Center for Psychoneuroimmunology - David Geffen School of Medicine at UCLA
Approved for 3.0 CE/Contact Hours
Level of Difficulty: Intermediate
CAMLT is approved by the California Department of Health Services as a CA CLS Accrediting Agency (#0021) and this course is is approved by ASCLS for the P.A.C.E.® Program (#519)
Notification of Distance Learning Deadline
This is a reminder that all the continuing education units required to renew your license/certificate must be earned no later than the expiration date printed on your license/certificate. If some of your units are made up of Distance Learning courses, please allow yourself enough time to retake the test in the event you do not pass on the first attempt. CAMLT urges you to earn your CE units early!
Completion of this course requires downloading the Acrobat Version (link above). You may then print a copy or view the downloaded file on your computer to see the course material. Only the Objectives and Introduction appear below.
After completing this course the participant will be able to:
• List the four hallmarks of antigen-specific immune responses
• Identify which innate white blood cells can serve as antigen-presenting cells in adaptive immune responses
• Match the appropriate class of MHC molecule to the T cell subset that requires it for antigen presentation
• Describe the role of CD4-expressing T helper cells in humoral and cell-mediated antigen-specific responses
• List one clinical laboratory technique that enumerates lymphocyte subsets, and at least one additional technique that provides information on immune system function
The immune system is constantly challenged to protect individuals from the enormous array of foreign materials to which they are exposed. The protection provided by the human immune system is a collaborative one, calling on both innate immunity, which is present in some form in all multicellular plants and animals, and adaptive immunity, which is a relatively recent product of evolution found in more advanced vertebrates (1). As reviewed in a previous course (2), the innate immune system prevents foreign materials, known as antigens, from gaining entry to the body through a variety of physical and chemical barriers. If a toxin, foreign protein, pathogen, or any other antigen succeeds in breaching these barriers, it would soon encounter a host of innate system cells and cellular defenses capable of preventing infection and/or eliminating pathogens and antigens from the body. While these cellular defenses can recognize and respond to foreign antigens, the innate immune system is relatively non-specific, i.e., it is not sufficiently specialized to discriminate between different types of foreign molecules. Although it is a highly-effective first line of defense against most infections and toxic exposures, the innate system does not always succeed in preventing disease. When disease is the outcome, the innate immune response serves as the critical first step in generating a more sophisticated and exquisitely specific adaptive, or acquired, immune response. Adaptive immunity is designed to recognize and eliminate a particular antigen in a very specific fashion, and to remember the antigen so as to be able to protect against it in the future. It is this combination of initial adaptive response and development of antigen-specific memory which is responsible for immunity as we know it.
Immunity is defined as “ the state of protection from infectious disease” (1). The concept is an ancient one, dating back to an epidemic, “The Plague of Athens,” in 430 BC, when an historian (Thucydides) observed that only those who had recovered from the disease could nurse the sick without becoming sick again themselves. The root of the word immunity is the Latin immunis, meaning “exempt,” reflecting the early understanding of exemption or protection from recurrent disease. Over the centuries, especially during the twentieth century and into the twenty-first century, scientists’ understanding of how the immune system accomplishes this feat has become more and more detailed. The primary goal of this course is to describe how the different types of white blood cells (WBC) interact with antigen and with each other to bring about adaptive antigen-specific immunity. In addition, the course will provide an overview of some of the specialized ways in which the status of the immune system can be evaluated in the clinical laboratory.