Phases of reaction: Sensitizaiton phase: The development of the DTH response begins with an initial sensitization phase of 1–2 w. after 1º contact with an Ag. Late effector phase: A 2nd. exposure to the Ag induces the effector phase of the DTH response: Th1 cells secrete cytokines that recruit and activate macrophages and other nonspecific inflammatory cells. A DTH response normally does not become apparent until 24 h after the second contac with the Ag; peaks 48-72 h after 2nd contact.
Direct and indirect activation of NK cells. The “classical” pathway of NK cell activation (A,B) results from skewing of the balance between signals transmitted via inhibitory and activating receptors. The “indirect” pathway of NK cell activation results from contact-dependent and soluble signals derived from accessory cells and T cells transmitted to activating receptors on NK cells (C).
Humeral Deficiencies (Immunoglobulins from B cells)... Hyper IgM = high IgM with low IgA and low IgG... This is caused by defective CD40 ligand... CD40 ligand usually induces the change from IgM to other immunoglobulins (class switching)... Also there will be decreased plasma/memory B cell formation and poor response to vaccines