Jitt # 9 Case Study Lepromatous Leprosy Flashcards
Th1 cells
From the CD4+ lineage; secrete IL-2, IFNg, and lymphotoxin (LT); enables the immune response to activate macrophages and cell-mediated immunity
Th2 cells
From the CD4+ lineage; secrete IL-4, IL-5, and IL-10; enables the response to produce antibody production only.
Th17 cells
From the CD4+ lineage; secrete IL-17
What are the four types of cells that CD4 cells can differentiate into upon recognizing a pathogen?
Th1, Th2 Th17, or Treg.
What cytokines are important for Th1 differentiation?
IL-12 and IFNg
What cytokine is important for Th2 differentiation?
IL-4
What factors influence T-cell phenotype?
cytokine(s) encountered; amount of antigen present; co-stimulation;
Positive Feedback Loop in Th1 cells.
Pathogens activate macrophages and NK cells (IFNg) , which produce IL-12; IL-12 causes Th1 differentiation; Th1 secretes IFNg; IFN g favors more Th1 development, but blocks the development of Th2 cells.
Positive Feedback loop in Th2 cells.
Pathogens, specifically parasites, cause IL-4 production by mast cells, eosinophils and thymus derived invariant NKT cells (iNKT cells), IL-4 is the cytokine that leads to Th2 differentiation; Th2 cells secrete IL-4 (more development) and IL-10 (blocks Th1 differentiation)
Symptoms of leprosy
loss of sensation (caused by bacterial infection of the schwann cells) , hypo-pigmented skin lesions (especially in the hands, ears, and buttocks) , hair-loss, nose bleeds (caused by mycobacterium infection in nasal tissue. leads to congestion and the break down of blood vessels)
Treatment for leprosy
dapsone, clofazamine, rifampin
Lepromatous Leprosy
Th1 (IL-12, IFNg)) cell mediated response is effective. If the Th2 response predominates, it is not effective; causes tissue damage;
Tuberculoid Leprosy
Associated with a vigorous cell-mediated Th1 (IL-1, IFNg, LT)response; activates macrophages to kill mycobacteria. Usually mild; lack suppressor CD8 T cells.
What organism causes lepromatous leprosy?
caused by mycobacterium leprae, which colonizes and multiplies within macrophages and other host cells; macrophages protect bacterium from attack by antibodies; can only be eliminated when macrophages are activated and produce microbicidal molecules;
What cytokines limit the response of Th1 cells? Where are they secreted from in lepromatous leprosy?
CD8 T cells secrete IL-10 and LT, which limit the immune response.
