More Objectives

I know some immunology, so what is it I am hoping to gain in the course?

I know, for example, that the immune system works to rid an organism of foreign invading organisms, including viruses.  The system has many different components, that is, different cell types that have different functions in performing this overall task.  I assume there are different types responsible for different threats.  There are cells and mechanisms involved in clearing viruses that are different from the cells and mechanisms for bacteria, and different ones for unicellular pathogens, and different ones for multicellular parasites.  There is redundancy within the system such that there are rapid responses and more long term remedies.  Immunization is the purposeful introduction of an antigen to elicit a response that is 'remembered' such that when a similar antigen from a real threat is perceived, a rapid response of the system can clear the infection before undesired consequences of infection can occur.

There are cell surface receptors and signals that 'turn on' or up-regulate the system, and others that 'turn down' or down-regulate the system.  Inflammation is one of the more obvious signs of the activated immune response.  Pathogens often have mechanisms that allows the pathogen to be undetected.  What are examples of those mechanisms?  Much is known about the immune system in undesirable function such as autoimmune diseases, sepsis, and cancer.  In autoimmune disease, the immune system attacks self.  What is the mechanism of dysfunction here?  In sepsis, an emergency response of sorts occurs such that the organism undergoes life-threatening temperature and organ failure.  How?  Why?  In cancers, rogue cells that are normally recognized and destroyed by the system are undetected and proliferate.  Why?  Cell and organ transplantation is challenged by immune response rejection.  How is this mediated?

I know about macrophages that engulf foreign matter to destroy it.  The mechanisms of destruction involve oxygen radicals, proteases, nucleases, and other degradative processes, but what are the details?  Apoptosis is a programmed cell death, but how is this process used in the immune system.  Antibodies have structures that bind to foreign antigens and are derived from shuffling variable regions of genes to generate diversity.  Through somatic cell selection, the antibodies with high affinity for the antigen are selected, and the cells proliferate to deliver antigen-binding immunoglobulins important in the immune response.  How is selection achieved?  What happens to the unselected cells?

There are a lot of questions.  Now on to some answers.