PNB 2265 Lecture 21: Defense part 3
16 Mar 2017
School
Department
Course
Professor
Document Summary
Antibody mediated - defends against free bacteria and viruses in body uids. Cell-mediated - defends against abnormal cells (cancer cells, viral infections, foreign cells, protozoa, fungi: antigen encounter and recognition by lymphocyte, lymphocyte activation and clonal expansion, attack. Both categories require activation of speci c helper t cells. Active acquired immunity: speci city, versatility, memory, tolerance. Regulatory function in both cell-mediated and antibody-mediated immunity. Give rise to antibody secreting plasma cells. 2 chained proteins which cannot bind antigen unless antigen is complexed to mhc proteins. Immunoglobin is copy of antibody that cell can produce. Confers speci city and versatility to speci c immune system. Igg -> typical antibody (80%), can cross placenta. Igm -> rst to appear after antigen. Iga -> saliva, tears, mucus, colostrum, breast milk, role in protecting mucosal surfaces. Histocompatibility - major histocompatibility complex proteins identify self . Recognized by cytotoxic t cells (cd8 receptors) Antigen presenting cells for helper t cells.
