THE IMMUNE RESPONSE

HONORS A&P

LEMON BAY HIGH SCHOOL

THE IMMUNE RESPONSEIMMUNITY:

• “FREE FROM BURDEN”

• ABILITY OF AN ORGANISM TO RECOGNIZE AND DEFEND ITSELF AGAINST SPECIFIC PATHOGENS OR ANTIGENS.

IMMUNE RESPONSE:

• THIRD LINE OF DEFENSE

• INVOLVES PRODUCTION OF ANTIBODIES

• GENERATION OF SPECIALIZED LYMPHOCYTES AGAINST SPECIFIC ANTIGENS.

ANTIGEN:

• MOLECULES FROM A PATHOGEN OR FOREIGN ORGANISM THAT PROVOKE A SPECIFIC IMMUNE RESPONSE.

THE IMMUNE SYSTEM IS THE THIRD LINE OF DEFENSE

AGAINST INFECTION

T - Lymphocyte activation

B - Lymphocyte activation and Production of

antibodies

COMPONENTS OF HUMAN IMMUNITY

CLASSIFICATION OF ACQUIRED IMMUNE

RESPONSES•NATURAL OR ARTIFICIAL•HOW WAS IMMUNE RESPONSE GAINED?

•CELL-MEDIATED OR HUMORAL•HOW IS THE BODY REACTING?

NATURAL VS. ARTIFICIAL

ACQUIRED IMMUNITYNATURAL: GAINED IN THE COURSE OF DAILY LIFE

NATURAL ACTIVE

•ANTIGENS/PATHOGENS ENTER THE BODY.

•BODY GENERATES AN IMMUNE RESPONSE.

•CAN BE LIFELONG (CHICKENPOX) OR TEMPORARY INFLUENZA).

NATURAL PASSIVE

•ANTIBODIES PASS FROM OTHER TO FETUS (PLACENTA) OR MOTHER TO BABY (BREAST MILK).

•NOT RESPONDING TO ANTIGENS.

•TEMPORARY ~ 8 WEEKS.

ACQUIRED IMMUNITYARTIFICIAL: GAINED THROUGH VACCINATION OR IMMUNE SERUM.

ARTIFICIAL ACTIVE

•ANTIGENS INTRODUCED THROUGH VACCINATION.

•BODY GENERATES AN IMMUNE RESPONSE TO THE ANTIGEN.

•CAN BE LIFELONG (POLIO) OR TEMPORARY (TETANUS).

ARTIFICIAL PASSIVE

•PREFORMED ANTIBODIES (ANTISERUM) INTRODUCED BY INJECTION.

•HOST IMMUNE SYSTEM DOES NOT RESPOND TO ANTIBODIES.

•TEMPORARY ~ 3 WEEKS

CELL-MEDIATED VS. ANTIBODY-MEDIATED

ANTIBODY-MEDIATED (HUMORAL) IMMUNITY• INVOLVES PRODUCTION OF ANTIBODIES AGAINST FOREIGN ANTIGENS.• ANTIBODIES ARE A CLASS OF PROTEINS PRODUCED BY B-CELL LYMPHOCYTES.• ANTIBODIES ARE FOUND IN EXTRACELLULAR FLUIDS (BLOOD PLASMA, LYMPH, MUCUS, ETC.) AND ON THE SURFACE OF B CELLS.• DEFENSE AGAINST BACTERIA, BACTERIAL TOXINS, AND VIRUSES THAT CIRCULATE FREELY IN BODY FLUIDS, BEFORE THEY ENTER CELLS.• ALSO CAUSE CERTAIN REACTIONS AGAINST TRANSPLANTED TISSUE.

ANTIBODIES ARE PROTEINS THAT RECOGNIZE SPECIFIC ANTIGENS

ANTIBODIES ARE PRODUCED BY B-CELL LYMPHOCYTES

T-CELL LYMPHOCYTES ARE PRODUCED IN THE THYMUS GLAND EARLY IN LIFE.

CELL MEDIATED IMMUNITY• INVOLVES T-CELLS LYMPHOCYTES THAT RECOGNIZE FOREIGN ANTIGENS.• T-CELLS REGULATE PROLIFERATION AND ACTIVITY OF OTHER CELLS OF THE IMMUNE SYSTEM.• DEFENSE AGAINST:• BACTERIA AND VIRUSES THAT ARE INSIDE HOST CELLS AND ARE INACCESSIBLE TO ANTIBODIES.• FUNGI, PROTOZOA, AND WORMS• CANCER CELLS• TRANSPLANTED TISSUE

ANTIGEN- ANTIBODY REACTIONS

CONSEQUENCES OF ANTIGEN-ANTIBODY BINDING

ANTIGEN-ANTIBODY COMPLEX: FORMED WHEN AN ANTIBODY BINDS TO AN ANTIGEN IT RECOGNIZES.

1. AGGLUTINATION: ANTIBODIES CAUSE ANTIGENS (MICROBES) TO CLUMP TOGETHER.• EXAMPLE: HEMAGGLUTINATION:

AGGLUTINATION OF RED BLOOD CELLS.

2. OPSONIZATION: ANTIGEN (MICROBE) IS COVERED WITH ANTIBODIES THAT ENHANCES ITS INGESTION AND LYSIS BY PHAGOCYTIC CELLS.

OVERVIEW OF THE IMMUNE

RESPONSE