Humoral Immunity Flashcards
Receptors on Mature Naive B-Cell
IgM, IgD, Ig-alpha & Ig-beta
Types of B-cells
B2
- Follicular ---- circulating in blood - Marginal ---- in spleen
B1
-Mucosa, limited specificity
What are common problems with vaccines?
1) Some specific viral epitopes can’t be used in a vaccine
2) Individual genetics
3) Allergic reactions
4) Does not work on the very young or old
Traits for a good vaccine
1) Safe
2) Provides long-lasting protection against LIVE pathogen
3) Inexpensive and easily distributed
What are some effector functions of Antibodies?
1) Opsonization and phagocytosis
2) ADCC - tagging for killing by NK
3) Direct neutralization via attaching to pathogen
4) Initiating the Classical Complement System
5) Therapeutics – IVIG for 1) rapid protection following pathogen exposure and 2) stopping autoimmune diseases by binding to Fc Receptors
What is a Follicle Dendritic cell
- Cell that resides in germinal center
- Decides which B-cell lives (high affinity) and which dies (low affinity)
- Creates Plasma cells and Memory B cells
B-Cell First Signal steps
1) Ag binds to the Ig on the B-cell
- Generally needs more than one Ag binding (cross-linking) to have stronger signal
2) Ig-alpha and Ig-beta transmit signal via phosphorylation of Syk
3) Syk phosphorylates adaptor proteins
4) Adaptor proteins initiate a signal cascade to a) GDP/GTP exchange with Ras & Rac and b) PLC-y activation ——-> NFAT, NFkB AP1 gene transcription
B-cell first signal outcomes
1) B-cell proliferation
2) Th interaction (as a result of Ag activation)
3) Migration to T-cell (upreg of CCR7)
4) Secretion of IgM
5) Increase cytokine receptors
B-Cell First signal amplifiers
1) Ag with bound C3d —- CD21 on B-cell binds to the C3d and causes enhancement of BCR signal
2) PAMP from Ag — PAMP binds to TLR and initiates TLR signal cascade that also amplifies the signal
Cytokine functions in the germinal center
1) Initiate class switching in the H chain (heavy chain)
2) Alter and proliferate B-cells into differentiated mature cells
