Mod2 Imm / Atopy Flashcards
Describe the two forms of immunity.
Innate- Immediate, General Protection, Non-specific, delivers unchanging effect, activates…. Adaptive Adaptive - Both cell-mediated and humoral immunity, customised responses, also protective responses via memorising foreign antigens.
Innate immune cells ?
Phagocytes - Macrophages(long lasting), Neutrophils (short lasting), APC/Dendritic cells (!).
Granulocytes - Eosinophils (helminths, watch !), Basophils (proteases, cytokines, HISTAMINE), Mast (HISTAMINE)
What cells are involved in Adaptive immunity ?
T Cells CD4+ and CD8+ in proportions of 60-70%CD4s. And B cells which go beyond just protein antigens.
But activated CD4+s via APCs then specialise into Th1 Th2 Th17 and Th22s ! They all produce cytokines called Interleukines that recruit the Innate immune cell groups !
Describe the effects of each of the T Helper cell sub-types
Th17 - IL-17A –> recruits neutrophils suring up mucosal barriers.
Th22- IL-22 –> recruits APCs/ inflammation, autoimmunity, tumours.
Th1 - IFNgamma & TNFbeta & IL-2 –> involved in inflammatory responses.
Th2 - IL 4,5,10,13s - assists humoral responses of Masts, B cells, Eosinophils, to produce antibodies called immunoglobulins !
Prime purpose of cytokines IL-4 and IL-13 ?
Th2 cells plus their 4/13 cytokines activate naive B cells to differentiate into Plasma Cells that produce IgEs…. migrate to INNate cells granulocytes ! These latter cells then release protein molecules: heparin, proteases and….HISTAMINE, that all drive pruritis.
So how do the Th2 cytokines affect the epidermis ?
IL4 IL13 - cause LESIONS —>
- Binding directly to keratinocytes that decreases differentiation !!! and so hyperplasia;
- Reduces filaggrin expression by keratinocytes;
- Th2 imbalances—-> indirectly floods/ induces infiltration of more immune cells into lesion that will produce more cytokines !!! ;
- Slows lows production of epidermal structural proteins and AMPs.
