The Question - QUIZ
An important defense against disease in vertebrate animals is the ability to eliminate, inactivate, or destroy foreign substances and organisms. Explain how the immune system achieves all of the following.

1. Provides an immediate nonspecific immune response

The human body has three levels of defense. The first two levels are both nonspecific, really. The skin, mucous lysosomes, and pathogen trapping philia are the first "line of defense" (UIC, The Immune System, uic.edu). The second line of defense is what is called the nonspecific response. Upon injury or entry of foreign material, the body releases phagocytes (pathogen/cell eaters), macrophage (which eat "just about anything"), leucocytes( which have digestive juices with which to destroy pathogens), and complement proteins (which upon activation turn into pathogen piercers) (UIC, ibid). The biochemical action is accompanied by inflammation( which encourages phagocytes and allows immune agents to leak out of blood vessels) and chemokines (which attract immune agents to the wound site)

Activates T and B cells in response to an infection

T cells are immue cells that mature in the thymus (OSU, The Immune System). They float around looking for macrophages with antigens. The act of bonding with an antigen carrying macrophage triggers cell replication into effector and memory daughter cells. All the daughter cells become specifically equipped with receptors for the first antigen they found. effector daughter cells produce interleukins that signal T and B cells to reproduce.

B cells produce a single type of antibody from the moment they mature. The antibodies stick out from the cell. When The B cells received inerleukins from a T cell, it begins to rapidly replicate into effector and memory B cells. the effector B cells produce a huge amount of antibodies which stick to pathogens. 

Responds to a later exposure to the same infectious agent

The antibodies produced for a specific disease never really go away, there are antibodies drifting around in the body for each disease you've gotten. The B cells in your body also retain information on the pathogens it has fought. When the body learns that a previously encountered pathogen is in the body again, it will launch a secondary response with b cells that act specifically against said pathogen. the response is "so fast and efficient that we are not aware we have been infected" (University of New Mexico, Immune Memory).

1. Distinguishes self from non self

All T cells are prevented from being autoimmune by undergoing maturation in the thymus. Most proteins in the body go through the thymus, and are exposed to the t cells. They thus become self tolerant. If any T cells have antibodies that attach to human protein, they are censored and eliminated. B cells only start pouring out antibodies if their receptors catch above a certain threshold of proteins and if T cells give them interleukin signals to do so. If a B cell has broken down a human protein, T cells usually do not give the interleukin signal to reproduce, and the B cell dies. (University of New Mexico, Tolerance).

http://www.cs.unm.edu/~immsec/html-imm/tolerance.html

http://www.cs.unm.edu/~immsec/html-imm/memory.html

http://medicalcenter.osu.edu/patientcare/healthcare_services/infectious_diseases/immunesystem/Pages/index.aspx

http://www.morphosys.com/technologies/antibodies/antibody-development-human-body