Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology
Antibodies (immunoglobulins, Ig)
There are 5 immunoglobulin classes remembered by the mnemonic GAMED: Ig G, A, M, E, D.
Greatest serum concentration, half-life and number of sub-classes
Macro -- largest Ig
Aggregates -- 2 units linked together
Alternative pathway of complement
Fc gamma receptors for IgG: CD 16, 32, 64 (double).
Fc gamma receptors for IgG (CD 16, 32, 64) are labeled in "reverse" order:
CD 16 - FcR III - low-affinity
CD 32 - FcR II - intermediate-affinity
CD 64 - FcR I - high-affinity
CD 16 and CD 56 are present on NK cells.
Fc II receptors:
CD 32 - Fc gamma II
CD 23 - Fc epsilon II, Fc receptors for IgE
CD32 down-regulates IgG. Binding of FcγRIIb is the proposed mechanism of action of IVIG.
Downregulation of IgG
Thirty-two, CD 32
Two, FcR gamma II
Turns downs (down regulates) IgG
CDs on Different Cells
T cells have CD 3, 4 and 8 (double, 4 x 2)
B cells have CD 19, 20 and 40 (double 20 x 2)
Stem cell CD 34+
Plasma cell CD 38+
Stem cell CD 34
Wiskott-Aldrich CD 43 defect
Interleukins: Hot T-Bone stEAk
IL-1: fever (Hot)
IL-2: stimulates T cells
IL-3: stimulates Bone marrow
IL-4: stimulates IgE
IL-5: stimulates IgA
B Cell Types (click to enlarge the image).