Immune_responses

The Immune Responses

Functions of the Immune System  Defense  Homeostasis  Surveillance

Antigens and Antibodies  Antigens

are substances not found in the

body.  Most antigens are proteins.

What is an antigen?

RESPONSE TO INVASION  PHAGOCYTOSIS  HUMORAL  CELL

IMMUNITY

MEDIATED IMMUNITY

TYPES OF IMMUNITY  Natural-active

– body has to work  Artificial-active – body has to work  Natural-passive – body receives/no effort  Artificial-passive –body receives/no effort

HUMORAL (ANTIBODIES) IMMUNE RESPONSE  Allows

for rapid local or systemic reaction to antigens

 Response

is to a specific antigen.

Cell-Mediated Immunity  Immunity

against:

 Pathogens

that survive inside cells (viruses and some bacteria)  Fungal infections  Rejection of transplanted tissues  Tumors  Contact hypersensitivity reactions

Cell Mediated Immune Response  T-Helper

cells (CD4) carry the “antigen message” to the lymph nodes where they help retain the “memory” for the antigen.  T-Helper cells secrete cytokines that rally other cells of the immune system.

CD8 Suppressor Cells  Keep

the balance  Decrease antibody reaction and prevent immune system “in check”.

HYPERSENSITIVITY REACTIONS  TYPE

I

 TYPE

II

 TYPE

III

 TYPE

IV