Give diagrammatic scheme of type 2 hypersensitivity reaction with name related to it
Type II Hypersensitivity - Antibody-Mediated (Cytotoxic) Reaction
KEY CONCEPT
Antibodies (IgG or IgM) directed against antigens on cell surfaces or extracellular matrix cause cell destruction through three main mechanisms.
DIAGRAM 1 - Mechanisms of Antibody-Mediated Injury (Robbins Pathology)
DIAGRAM 2 - Antibody-Dependent Cytotoxicity (Roitt's Essential Immunology)
SCHEMATIC OVERVIEW
ANTIGEN on Cell Surface / Extracellular Matrix
|
▼
IgG / IgM Antibody Binds
|
┌─────────┼──────────────┐
▼ ▼ ▼
MECHANISM A MECHANISM B MECHANISM C
Opsonization Complement Antibody-Mediated
& Phagocytosis Activation Cellular Dysfunction
| | |
▼ ▼ ▼
Fc receptor C1→C3→C5 Anti-receptor
on phagocyte activation antibody
| | |
▼ ┌────┴────┐ ▼
Phagocytosis ▼ ▼ Blocks/stimulates
of opsonized C5a→ C5b-9→ normal receptor
cells Neutrophil MAC function
recruitment |
↓ ▼
Inflammation Cell Lysis
Tissue Injury
THREE MECHANISMS IN DETAIL
A. Opsonization & Phagocytosis
- Antibody coats (opsonizes) the cell
- Phagocytes recognize via Fc receptors (IgG) or C3b receptors (complement)
- Cell is ingested and destroyed
- Mainly occurs in the spleen
B. Complement Activation + Inflammation
- IgG/IgM binds antigen on cell or tissue
- Classical complement pathway activated: C1 → C4 → C2 → C3
- C3 cleaved into C3b (opsonin) + C3a (anaphylatoxin)
- C5 cleaved into C5a (chemotaxis, anaphylatoxin) + C5b
- C5b-C9 forms MAC (Membrane Attack Complex) → cell lysis
- C5a attracts neutrophils → degranulation → tissue injury
C. Antibody-Dependent Cellular Cytotoxicity (ADCC)
- Target cells coated with IgG are killed by NK cells, monocytes, neutrophils, eosinophils
- Effectors bind via FcγR receptors (not phagocytosis)
- Extracellular killing - important for large targets (parasites, tumors)
DISEASES ASSOCIATED WITH TYPE II HYPERSENSITIVITY
| Disease | Target Antigen | Mechanism | Manifestation |
|---|---|---|---|
| Autoimmune Hemolytic Anemia | RBC membrane proteins | Opsonization + phagocytosis | Hemolysis, anemia |
| Hemolytic Disease of Newborn (Erythroblastosis fetalis) | Rh antigen on fetal RBCs | Maternal IgG crosses placenta, destroys fetal RBCs | Fetal anemia, jaundice |
| Transfusion Reaction (ABO mismatch) | ABO blood group antigens | Complement lysis + phagocytosis | Acute hemolysis |
| Autoimmune Thrombocytopenia | Platelet GpIIb:IIIa integrin | Opsonization + phagocytosis | Bleeding |
| Goodpasture Syndrome | Collagen IV in GBM and alveoli | Complement + Fc-mediated inflammation | Nephritis, lung hemorrhage |
| Myasthenia Gravis | Acetylcholine receptor (NMJ) | Antibody blocks receptor; complement injury | Muscle weakness, paralysis |
| Graves' Disease | TSH receptor on thyroid | Antibody stimulates receptor (mimics TSH) | Hyperthyroidism |
| Pemphigus Vulgaris | Desmoglein (epidermal junctions) | Protease activation, loss of cell adhesion | Skin bullae |
| Acute Rheumatic Fever | Streptococcal Ag cross-reacts with myocardial Ag | Inflammation, macrophage activation | Myocarditis, arthritis |
| Pernicious Anemia | Intrinsic factor (gastric parietal cells) | Neutralization of IF → ↓ Vit B12 absorption | Megaloblastic anemia |
KEY POINTS FROM YOUR NOTES (Confirmed)
- RBCs have intrinsic Ag on surface - correct (e.g., ABO, Rh antigens)
- B cells & T cells get activated - B cells produce the IgG/IgM antibodies
- IgG/IgM production - the effector antibodies of Type II
- C3, C3b, C5 - complement cascade cleavage products
- C5a, C4a, C5a attract neutrophils - chemotactic fragments
- Neutrophils are cytotoxic to cells via degranulation
- Type II = Hypersensitivity rxn - confirmed
- Examples noted: Rheumatic fever, Erythroblastosis fetalis, petty (petechiae in ITP)
Make diagramatic scheme from my information only no extra
A clean medical diagram flowchart of Type II Hypersensitivity Reaction based on these exact notes, white background, clear black text with colored boxes and arrows: TOP SECTION - Title box: "What happens during Type II Rx?" with subtitle "Also known as: Hypersensitivity (Type-2) / Humoral - Complex mediated" STEP 1 box (light blue): "RBCs have Intrinsic Ag on their surface" with small circle labeled "RBC" showing dots on surface STEP 2 box: Arrow down → "B cells & T cells get activated" STEP 3 box: Arrow down → "Production of IgG / IgM" STEP 4 box: Arrow down → "IgG / IgM activated" then "First C1, C2 is adopted → they bind to Fc region of Ab" STEP 5 - Split into TWO BRANCHES with arrows: LEFT BRANCH (orange box): "C3 → C3b (cleavage of C3)" label: "Complement System" → then splits to: - "C5a, C4a, C5a" → "attract neutrophils" → "they are cytotoxic to cells" → "tissue damage" → "autoimmune reactions" → "Type II - Hypersensitivity Rxn" RIGHT BRANCH (pink box): "C5 → C5b-C9" → "MAC (Membrane Attack Complex)" → "lysis by complement mechanism" BOTTOM LEFT box (yellow): "Neutrophils → RBC lysis" BOTTOM EXAMPLES cloud shape: "Examples: Rheumatic fever, Erythroblastosis fetalis, Petty (ITP)" BOTTOM RIGHT note: "also known as: Humoral - Complex mediated / Motion Ab → Petty / Haemolytic anaemia" Use medical textbook style, neat flowchart with colored arrows, clear font size 14+, boxes with rounded corners
- RBCs have intrinsic Ag on their surface
- B cells & T cells get activated
- Production of IgG / IgM
- IgG / IgM activated
- First C1, C2 is adopted → they bind to Fc region of Ab
- Family of proteins that work via complement system (lysis + destroying mechanism)
- Also known as: Hypersensitivity (Type-2) / Humoral-complex mediated
- C3 → C3b → C5 → C5b-C9 (cleavage)
- C5a, C4a, C5a → attract neutrophils
- They are cytotoxic to cells → tissue damage → autoimmune reactions → Type II Hypersensitivity Rxn
- Neutrophils = RBC lysis
- Examples: Rheumatic fever, Erythroblastosis fetalis, Petty (ITP)
- Motion Ab → Petty / Haemolytic anaemia
I am asking diagram
A detailed medical science flowchart diagram on white background titled "TYPE II HYPERSENSITIVITY REACTION" at the top in bold dark blue. The diagram flows top to bottom with labeled boxes, arrows, and small illustrations: [BOX 1 - light blue rounded rectangle] RBC (draw a small red blood cell circle with dots on surface labeled "Intrinsic Ag on surface") ↓ arrow [BOX 2 - light green] B cells & T cells GET ACTIVATED (draw small lymphocyte cells) ↓ arrow [BOX 3 - light yellow] Production of IgG / IgM (draw Y-shaped antibody symbols) ↓ arrow [BOX 4 - light orange] IgG / IgM bind to Fc region of Ab First C1, C2 adopted → bind to Fc region (draw antibody binding to cell surface) ↓ arrow splits into TWO PATHS with a horizontal line: LEFT PATH (pink boxes connected downward): [C3 activated] ↓ [C3 → C3b + C3a] ↓ [C5 → C5b-C9] ↓ [MAC formed] ↓ [CELL LYSIS] (draw broken cell) Label on side: "Complement System - lysis by destroying mechanism" RIGHT PATH (orange boxes connected downward): [C5a, C4a produced] ↓ [Attract NEUTROPHILS] (draw neutrophil cell) ↓ [Neutrophils cytotoxic to cells] ↓ [Tissue Damage] ↓ [Autoimmune Reactions] ↓ [TYPE II - HYPERSENSITIVITY Rxn] BOTTOM SECTION - two cloud/bubble shapes: Left cloud: "EXAMPLES: Rheumatic fever | Erythroblastosis fetalis | Petty (ITP) | Haemolytic anaemia" Right box: "Also known as: Humoral-Complex Mediated Hypersensitivity | Motion Ab → Petty | Haemolytic anaemia" Style: clean medical textbook illustration, color-coded pathways, neat arrows, labels clearly visible, professional academic diagram