Complement protective factors activated t and b

Complement
Protective factors
 Activated T and B lymphocytes
 Cytokines AND Antibodies

DIFFERENCE BETWEEN CELL MEDIATED & HUMORAL
T-CELLS or T-LYMPHOCYTES: come from Lymphoid Stem cells in the bone marrow. They migrate and further
mature in the THYMUS . They are considered immunocompetent but are still not fully mature cells. They migrate to
Spleen or Lymph nodes (or other secondary lymphoid organs) where they remain dormant until activated to undergo
the 2
nd
phase of maturation.
2
nd
phase of maturation = Clonal Selection occurs after they are stimulated by an Antigen Presenting Cell to further
differentiate into a T-Cell with specific receptors for a specific antigen. (antigen presenting cell can be almost any
cell that can process a given antigens inside the cell and then display a “marker” or /antigen-specific receptor on
its surface that attracts the attention of the T-cells or other immune cells.
Cell-Mediated immunity is that Immunity conferred by a variety of T-Cells with various functions. Immunity is
active against cells infected with intracellular Bacteria or Viruses .
It defends against:
 fungal
 parasitic infections
 tumors
 responsible for organ transplantation rejection.
T-Cells or T-Lymphocytes, come in different varieties and are classified by “cluster of differentiation” CD for short.
We need to know 4 types for the test. Some are commonly known by several names.
 T-HELPER CELLS (CD4 /T4cells) (HELPERS) *Important * many functions
This group of T cells helps the antigen-driven maturation of both B & T cells. They perform this task by
facilitating & magnifying the interaction between
APCs (antigen presenting cells) & the immune-competent lymphocytes.
ACTIVATES
o macrophages
o B-cells, (activate B-cells with chemical messengers CYTOKINES to mature into plasma cells that can produce antibodies)
o Cytotoxic T-cells
o other T-helper/CD4 cells.
RELEASES
o lymphokines that begin the inflammatory process .
o Subgroups of the T-helper cells/CD4 cells like, TH1 and TH2 , release the lymphokines. *in lecture notes*
MEDIATES
o Mediates delayed hypersensitivity reactions such as the TB skin test . *from lecture notes*

CYTOTOXIC-T CELLS
- (Cytotoxic cells/ CD8/T8cells/ T-killers/Tc)
KILLS: Releasing cytotoxic chemicals that destroy the cell membrane
Or inducing apoptosis
o virus infected cells
o tumor cells
o allograft cells (transplant tissue) (from his lecture)
 *Memory T-cells*:
not on his outline organizer but in his lecture( page2)
allow the host to remember antigens and respond quicker and more vigorously after the initial exposure.
They live for many years and* can reproduce themselves

T-regulatory cells
: slow or stop the immune response after invader is destroyed

EXAMPLE OF HOW CELL MEDIATED IMMUNITY WORKS.