Immune Cells

Erythrocyte

Red blood cell that transports oxygen throughout the body

Neutrophil

Granulocyte and phagocyte serving as the most abundant immune cell in the body and first line of defense in acute inflammation that is involved in Type III hypersensitivity and ejects chromatin to NET pathogens

Eosinophil

Granulocyte fighting parasites and mediating allergic reactions

Basophil

Blood granulocyte releasing inflammatory mediators during allergic reactions

Mast Cell

Tissue-resident granulocyte releasing inflammatory mediators during allergic reactions

Megakaryocyte

Bone marrow precursor cell that produces platelets

Dendritic Cell

Phagocytic antigen-presenting cell patrolling peripheral tissues

Monocyte or Macrophage

Phagocytic antigen-presenting cell capable of activation with specialized tissue-specific types

Kupffer Cells

Specialized macrophages residing in the liver

Microglial Cells

Specialized macrophages residing in nervous tissue

Mesangial Cells

Specialized macrophages residing in the kidneys

B Cell

Lymphocyte producing antibodies and utilizing membrane-bound IgD or IgM as its antigen receptor

Plasma Cell

Fully activated B lymphocyte that secretes large amounts of antibodies

Helper T Cell (Th)

CD4+ lymphocyte directing adaptive immunity by releasing cytokines

Cytotoxic T Cell (Tc)

CD8+ lymphocyte destroying target cells via granzymes and perforin in the kiss of death

Regulatory T Cell (Treg)

T lymphocyte regulating immune responses and maintaining antigen tolerance using distinct cytokines

Natural Killer (NK) Cell

Innate lymphocyte destroying virally infected cells and tumor cells

IgM

Monomeric form acts as a BCR on B cells but functions as a pentamer when secreted to participate in complement activation and neutralization and agglutination

IgD

Membrane-bound antibody acting primarily as the B cell receptor or BCR

IgG

Most abundant antibody class in serum capable of crossing the placenta to mediate complement activation and neutralization and opsonization and agglutination

IgE

Antibody facilitating allergic reactions and inflammation and parasitic responses by triggering eosinophils to release antiparasitic molecules and basophils to release histamine

IgA

Dimeric antibody abundant in secretions such as mucous membranes or breast milk with primary functions in neutralization and agglutination

Type I Hypersensitivity

Immediate IgE-mediated allergic reaction occurring within seconds to minutes after exposure with example including asthma

Type II Hypersensitivity

Cytotoxic reaction where cells are destroyed by complement and IgM or IgG antibodies with examples including hemolytic disease of the newborn and drug-induced hypersensitivity

Type III Hypersensitivity

Immune-complex mediated reaction causing tissue damage due to the buildup of antigen-antibody complexes with examples including rheumatoid arthritis and lupus and hypersensitivity pneumonitis and glomerulonephritis

Type IV Hypersensitivity

Cell-mediated reaction with delayed onset taking 24 to 48 hours with examples including tuberculin response and allergic contact dermatitis from poison ivy or latex and graft rejection

Allergens

Specific antigens that trigger Type I immediate hypersensitivity reactions