Expert-level immunology covering innate and adaptive immunity, antibody structure and function, T cell biology, immune evasion, vaccines, autoimmunity, and immunotherapy.
Physical barriers: skin, mucosa, cilia, antimicrobial peptides. Pattern recognition: PRRs (TLRs, NLRs, RLRs, CLRs) detecting PAMPs and DAMPs. Innate cells: neutrophils, macrophages, NK cells, dendritic cells, mast cells. Complement system: classical, lectin, alternative pathways — C3, C5, MAC. Inflammation: cytokines (IL-1, IL-6, TNF), chemokines, acute phase response.
Lymphocyte development: B cells (bone marrow), T cells (thymus). Antigen presentation: MHC-I (CD8+ T cells), MHC-II (CD4+ T cells). Clonal selection: antigen-specific receptor triggers proliferation and differentiation. Immunological memory: long-lived plasma cells, memory T cells.
Structure: two heavy chains, two light chains, Fab (antigen binding), Fc (effector). Isotypes: IgM (first response), IgG (main serum), IgA (mucosal), IgE (allergy). Affinity maturation: somatic hypermutation in germinal centers. Class switching: same variable region with different constant region. Effector functions: neutralization, opsonization, ADCC, CDC.
CD4+ helper: Th1 (cellular), Th2 (humoral), Th17 (mucosal), Treg (suppression). CD8+ cytotoxic: perforin/granzyme, Fas-FasL killing of infected cells. TCR signaling: CD3 complex, ZAP-70, LAT, PLC-gamma — calcium, MAPK, NF-kB. Checkpoints: PD-1, CTLA-4, TIM-3 — prevent autoimmunity, exploited by tumors.
Vaccine types: live attenuated, inactivated, subunit, mRNA, viral vector. Adjuvants: alum, MF59, AS01 — enhance innate activation and APC maturation. Checkpoint inhibitors: anti-PD-1, anti-CTLA-4 — reinvigorate exhausted T cells. CAR-T cells: engineered T cells with chimeric antigen receptor for cancer.
| Pitfall | Fix |
|---|---|
| Conflating innate and adaptive timelines | Innate: minutes-hours, Adaptive: days-weeks |
| Ignoring Treg suppression | Always check Treg compartment in autoimmunity studies |
| Assuming mouse data translates to human | Many cytokine functions differ between species |
| Overlooking non-classical MHC | NKT cells, MAIT cells use non-classical presentation |