B and T cell

what are the 2 subsets of T cells

• helper T cells(CD4)

• cytotoxic T cells (CD8)

How do T cells and B cells achieve the diversity in their receptors that allow them to recognize only one specific

VDJ recombination

what does VDJ stand for

• Variable

• diversity

• joining

In the thymus the T cells undergo an examination process to achieve what 2 things?

• ensure that each T cell responds to its antigen

• no self response

Freshly made T cells are considered ________ T cells

naive

What are 3 steps necessary to T cell activation

1. antigen presented via MHC

2. co-stimulation via accessory surface molecules

3. cytokine stimulation

The determining factor between a cell mediated response and an humoral response is ___________

the T helper cell

like macrophages and nuetrophils cytotoxic T cells can initiate direct cell killing however theirs is ___________

antigen specific

3 major mechanisms of cytotoxic T cell killing

1. perforin cell lysis

2. cytokines

3. FasL/Fas interactions

After activation and clearing of pathogen T cells die via ___________

contraction

NK cells are important in regards to killing what 3 types of cells

1. virus infected cells

2. cancer cells

3. stressed cells

without antigen specificity how can NK cells sense target cells

• downregulation of MHC 1

• antibody deposition

where does VDJ recombination occur for B cells

Bone marrow

The largest antibody and usually the first secreted during new infections is what

IgM

the main antibody present in a primary response is ____

IgM

smallest antibody and is in highest concentration in circulation and is the main antibody present in the secondary response

IgG

has a role in hypersensitivity and in parasite directed immune responses is what antibody

IgE

antibody secreted at a mucsoal surface and is present as a dimer alongside with a secretory component is _______

IgA

T helper 1 cells lead to a more __________ response

cell mediated

T helper 2 cells lead to a more __________ response

humoral

Which response is better for viruses and intracellular bacteria

cell mediated

which response is better for extracellular organisms

humoral response