C2 - LESSON 2: ACQUIRED IMMUNITY Flashcards
Allows the body to recognize, remember, and respond to a specific stimulus, an antigen.
Third Line of Defense: Adaptive Immunity
Results in the elimination of microorganisms and recovery from disease and the host often acquires a specific immunologic memory which allows the host to respond more effectively if reinfection with the same microorganism occurs.
Third Line of Defense: Adaptive Immunity
Cells of the Adaptive Immune Response
- B Lymphocytes
- T Lymphocytes
- Natural Killer Cells
Lymphocytes: key cells involved in the immune response
20-40%
Lymphocytes:
: 7-10um
Typical small lymphocyte
large rounded nucleus that is indented
Lymphocytes:
Nuclear chromatic: dense and stains deep blue
Lymphocytes:
Cytoplasm stains a lighter blue
Lymphocytes:
Contains few organelles and with no granules
Lymphocytes:
➔ mature in the bone marrow and differentiate into plasma cells that produce antibodies.
B Lymphocytes
➔ Recognize via membrane bound antibodies- can recognize many different chemical structure
B Lymphocytes
B Lymphocytes ➔ Surface markers:
CD19, CD20, CD21, CD40 and MHC class II molecules
➔ Develop in the bone marrow
B Lymphocytes
➔ Found in bone marrow, spleen, lymph nodes
B Lymphocytes
➔ Identified by surface immunoglobulin
B Lymphocytes
➔ End product of activation is antibody
B Lymphocytes
➔ Located in cortical region of lymph nodes
B Lymphocytes
➔ mature in the thymus and serve a regulatory role by providing help to B cells in responding to antigens as well as by killing virally infected target cells.
T Lymphocytes
➔ can only recognize peptide fragments that are presented by Antigen presenting cells via molecules known as MhC (present on surface of APC)
T Lymphocytes
T Lymphocytes ➔ Antigens include
CD2, CD3, CD4, CD8
➔ Located in paracortical region of lymph nodes
T Lymphocytes
➔ Develop in the thymus
T Lymphocytes
➔ Found in blood (60–80% of circulating lymphocytes), thoracic duct fluid, lymph nodes
T Lymphocytes
➔ Identified by rosette formation with SRBCs
T Lymphocytes
➔ End products of activation are cytokines
T Lymphocytes
2 subsets of T cells which proliferate when stimulated
- CD4+ helper T cell
2.CD8+ cytotoxic T cell
secretes soluble molecules which helps B cell to produce antibodies and activates macrophages
- CD4+ helper T cell
secretes soluble mediators-play important role in killing virus infection and tumor cells
2.CD8+ cytotoxic T cell
Have the ability to kill target cells without prior exposure to them
Natural Killer (NK) Cells
Larger than T and B cells (15 um in diameter)
Natural Killer (NK) Cells
10-15% of the circulating lymphoid pool
Natural Killer (NK) Cells
No surface markers that are unique to NK cells
Natural Killer (NK) Cells
Play an important role as a transitional cell bridging the innate and the adaptive immune response against pathogens
Natural Killer (NK) Cells
TYPES OF ACQUIRED IMMUNITY
➔ Immunity induced by exposure to a foreign antigen
Active Immunity
➔ It is the resistance developed by an individual after contact with foreign antigens
Active Immunity
- acquired by natural clinical or subclinical infections.
Natural Active Immunity
- Long- lasting
Natural Active Immunity
- induced in individuals by vaccines
Artificial Active Immunity
- These may be live vaccines, killed vaccines, or vaccines containing bacterial products
Artificial Active Immunity
Mediated by antibodies
ACTIVE Humoral Immunity
Involves immunoglobulin (antibody) production by B lymphocytes.
ACTIVE Humoral Immunity
Complement can also be considered a humoral component because it can be activated by immunoglobulin.
ACTIVE Humoral Immunity
Principal defense mechanism against extracellular microbes
ACTIVE Humoral Immunity