What are the 5 mechanisms of antibody action? 

Open a "CAN OF" antibodies:

Clumping, Activation of compliment proteins,

Neutralization, Opsonization, and Flagging 

Describe neutralization. 

Antibodies "neutralize" bacterial toxins or viruses by covering sites on toxin molecules that would otherwise interact with susceptible host cell membranes. 

Describe opsonization. 

During opsonization, antibodies coat viruses and microbes so they can be phagocytized.

Describe clumping. 

During clumping, antibodies localize the antigen, allowing defenses to be focused in one area. Clumping also makes it possible for phagocytes to engulf a number of antigens in "bite." 

Describe the activation of compliment proteins. 

The bariable region of the antibody binds to antigenic determinants. The constant region of the bound antibody activates the first compliment protein, starting a cascade of compliment protein activation resulting in chemotaxis of phagocytes, inflammation, lysing of foreign cells, etc. 

What is the special benefit of antibodies being able to activate compliment proteins? 

The enzyme is activated right where it is needed, the site where a specific antigen determinant is needed. 

Describe flagging. 

Some antibodies flag cells so that various defensive cells can efficiently find problem cells and take action. 

The presence of ___ means that the second exposure to a particular antigen will produce a more more rapid and intense immune response to that antigen. 

memory cells 

Antibody levels peak about ___ weeks after exposure. 

two 

How do antibody levels differ between first and second exposure to an antigen? 

Antibody levels rise sooner after the second exposure, reach higer levels, and they stay high longer. 

How can you account for the difference in antibody response between first and second exposures? 

The primary response produced memory cells. 

Define active immunity. 

Active immunity is the resistance to infection that results because of the presence of memory cells for a particular antigen. 

A person with memory cells for a particular antigen could have been exposed to the antigen in one of two ways. What are they? 

infection and vaccination 

What are the three forms in which vaccinations expose people to antigens? 

dead or weakened viruses, parts of bacteria and viruses, altered bacterial toxins 

Why is passive immunity temporary? 

Passive immunity is temporary because the donated antibody molecules break down in weeks or months. 

Give two examples of passive immunity. 

antibodies passed to a child through placenta or milk, and antibodies from the blood of another person or an animal 

Name three types of immune disorder. 

immunodeficiencies, allergies, auto-immune disease 

What is the difference between congenital and acquired immunodeficiencies? 

Congenital immunodeficiencies are due to genetic or developmental abnormalities; while acquired immunodeficiencies are the result of cancer or a virus. 

Define allergy. 

Allergies are abnormally vigorous immune responses during which the immune system causes tissue damage as it fights off a threat that would otherwise be harmless. 

What do we call it when a person develops an immune response to certain of their own molecules? 

auto-immune disease 

Give three examples of auto-immune disease. 

multiple schlerosis, rheumatoid arthritis, insulin-dependant diabetes mellitus 

Why do cytotoxic T-cells attach cells of donated organs. 

Cytotoxic T-cells attach cells of donated organs because they include surface molecules that are different from those of the recipient.

Why can't everyone accept a transfusion of blood from anybody? 

The surfaces of RBCs contain molecules that can be antigenic. 

Name the blood types in order of greatest prevalence. 

O, A, B, AB 

We are all exposed to antigens ___ We don't make antibodies to ___ if they are part of our own RBCs. 

A and B, A and B 

About ___% of people are Rh positive;

___% are Rh negative? 

85%, 15% 

When might an Rh- person be exposed to Rh+? 

A person might be exposed to Rh+ in the case of a blood transfusion or when a mother carries an Rh+ fetus. 

Why does an Rh person's first exposure to Rh antigen usually have no observable ill effects? 

Antibodies take a while to develop and antibody events are not high. 

Why would happen if a person with type O blood were given a transfusion from a person with type A blood? 

First, donated RBCs would be clumped by anti-A antibodies in the recipient's plasma. Then the clumped cells would block small blood vessels. Clumped RBCs would rupture and release homoglobin, which can precipitate in the kidneys and impair kidney function. 

How many human erythrocyte antigen systems are there? 

15 

How could you test blood compatibility? 

Mix RBCs from the donor with plasma from the recipient if you want to test blood compatibility. If no clumping occurs, the blood is considered an adequate match. 

In an extreme emergency, what type of blood could be administered to anyone? 

O