An introduction to the vertebrate immune system with emphasis on molecular and cellular events. Topics include organization of the immune systems, structure and function of immunoglobulins, genetics of immunoglobulin diversity, clonal selection theory, complement-mediated processes, the major histocompatibility complex, cell-mediated responses, immunization, innate immunity, autoimmunity, and immunodeficiency. Non-laboratory course. This course cannot be taken for credit if the student has already received credit for BIOL 330. Prerequisite: BIOL 233 and BIOL 243.