Basic Concepts

Immunology is the study of resistance to infection and rejection of foreign substances. Man's immune system is based on several concepts.

1. Memory: first contact with a foreign antigen imprints memory, through the production of memory T and B lymphocytes, so that the body will recognize and attack the antigen when it is encountered in the future.

2. Specificity: the protection is usually specific, i.e., directed only against the original infecting organism.

3. Recognition of non-self: the immune system has the ability to recognize only antigens that are foreign or "non-self". Self-tolerance is something our immune system presumably develops during fetal life.

Tolerance

Immune tolerance occurs when persons fail to make an antibody even though they are exposed to foreign antigens. This can occur for a number of reasons, including too low a dose of the foreign antigen; poor immunogenicity of an antigen; immune response genes which make the person a poor responder. Immune paralysis is a type of immune tolerance in which the immune system becomes paralyzed because it is overwhelmed with seeing too many foreign antigens all at once. Self tolerance is the basic rule of immunity in which a person only makes antibody against foreign antigens (but not self-antigens).

Enrichment activity #1

There are many educational sites on the WWW dealing with immunity. Visit humoral immunity and based on the information, answer the following questions. E-mail responses to Pat.

1. How does the author define these terms?

   (a) epitope

   (b) antigen

   (c) paratope

   (d) hapten

   (e) immunogenicity

2. Innate and acquired immunity discusses how the body protects against micro-organisms. What are the characteristics of innate immunity?

3. How does innate immunity differ from adaptive (acquired) immunity?

4. Which type of immunity is involved when patients form antibodies to red cell antigens?

Basic Concepts