T Cell Effector Function Flashcards
What are the 4 possible effector T cell types?
Th1 - activates macrophages
Th2 - B cell isotype switching
Th17 - Promote inflammation by neutrophils
Treg - Inhibit T cell functions
What are the effector functions of T Helper cells?
Activate CTL and macrophages
Help in antibody production
Help maintain inflammation
Help get rid of parasites
What are the effector functions of cytolytic T lymphocytes?
Kill cells harboring intracellular pathogens
Distinguish uninfected from infected cells
Secrete cytokines
Kill tumor cells
What is the difference between activation of naive T cells and effector T cells?
Activation requires costimulation with CD80/86
Effector function only requires MHC/TCR binding
How do CTL cause cell death?
CTL induced apoptosis
What proteins are contained within the CTL graunules?
Perforin - form pores
Granzymes - serine proteases
Granulysin - induce apoptosis
How are T cells inactivated?
As pathogen is cleared, T cells begin to express CTLA4 which binds with high affinity to CD80/86 (B7) on APC
This inhibits T cell activation
What cells can inhibit a T cell response?
Suppressor T cells (Tregs) - secrete IL-10 and TGFB
Myeloid Derived Suppressor Cells - arginase production and TGFB
What are memory T cells?
Generated at the end of the adaptive response, at the point where the pathogen is cleared
What are the functions of IL-2 and IL-7/15?
IL-2: Proliferation of T cells following antigen exposure
IL-7/15: survival of T cells following activation
What are the three types of memory T cells?
Central - remain in lymphoid tissue (lymphoid and spleen)
Effector - Migrate to tissue, circulate
Resident - don’t recirculate like the other two, remain at the site of exposure
How are macrophages activated?
Interaction between class II proteins on the macrophage and TCR of helper T cells (Th1 effector cells)
What changes do activated macrophages undergo?
Increase expression of CD40 and TNF receptors
Secrete increased amounts of TNFa (autocrine stimulation)
Autocrine stimulus synergizes with IFN-y
What do macrophages do to increase their antimicrobial activity after activation?
Increased NO production
Increased superoxide production
Increased B7 expression
Increased MHC II expression
How do B cells produce antibodies?
BCR binds antigen and the complex is internalized
Following cytokine release, a modified form of the BCR is transcribe and translated and secreted
What division of immunity is generation of antibodies considered?
Humoral immunity, a part of the adaptive response
What part of immunity do antibodies provide their function in?
The innate immune response
Can the antibody response improve?
Yes, affinity maturation occurs along with isotype switching
What is the T-independent antibody response?
Does not require interaction with a T cell or an APC
B1 cells bind pathogen and gets turned on directly
Usually IgM against bacteria, function in innate responses
What is T-dependent antibody response?
Must interact with Tfh that has been activated by a DC
B2 cells
Majority of antibody
What are the differences in antibodies produced from the T-independent and T-dependent response?
T-independent: IgM, natural antibodies that function early in innate immunity
T-dependent: IgM, IgG, IgA, IgE, each have a specific structure and function
