Immune cells

Neutrophils

Function: Rapid phagocytosis of bacteria & fungi; Role: First responders to infection; form pus; Immunity Type: Innate immunity

Macrophages

Function: Phagocytosis; release cytokines; Role: Antigen presentation to T cells; tissue cleanup; Immunity Type: Innate immunity (bridge to adaptive)

Dendritic Cells

Function: Capture antigens; migrate to lymph nodes; Role: Primary antigen-presenting cell for activating naïve T cells; Immunity Type: Innate → activates adaptive

Natural Killer (NK) Cells

Function: Kill virus-infected cells and tumor cells; Role: Recognize cells lacking MHC I; Immunity Type: Innate immunity

Basophils

Function: Release histamine, leukotrienes; Role: Mediate allergic inflammation; bind IgE; Immunity Type: Innate immunity

Mast Cells

Function: Release histamine & granules upon IgE cross-linking; Role: Major effector in allergies & anaphylaxis; Immunity Type: Innate immunity (but interacts with adaptive IgE)

Eosinophils

Function: Kill parasites via granules; modulate inflammation; Role: Major defense against helminths; involved in allergies; Immunity Type: Innate immunity

Monocytes

Function: Circulating precursors to macrophages; Role: Enter tissues to differentiate into macrophages or dendritic cells; Immunity Type: Innate immunity

B Cells

Function: Produce antibodies; Role: Differentiate into plasma cells; antigen presentation; Immunity Type: Adaptive (humoral) immunity

Plasma Cells

Function: Secrete large amounts of specific antibody; Role: Effector stage of B cells; Immunity Type: Adaptive (humoral) immunity

Memory B Cells

Function: Long-term antibody memory; Role: Rapid, high-affinity response upon re-exposure; Immunity Type: Adaptive (humoral) immunity

CD4⁺ T Helper Cells

Function: Secrete cytokines to coordinate immune response; Role: Activate B cells, macrophages, CD8 cells; Immunity Type: Adaptive (cell-mediated + humoral coordination)

Th1 Cells

Function: Activate macrophages & cytotoxic responses; Role: Combat intracellular pathogens; Immunity Type: Adaptive (cell-mediated)

Th2 Cells

Function: Stimulate B cells to produce antibodies (especially IgE); Role: Defense against parasites; allergy mediation; Immunity Type: Adaptive (humoral)

Th17 Cells

Function: Recruit neutrophils; Role: Defense against extracellular bacteria/fungi; Immunity Type: Adaptive (cell-mediated)

Regulatory T Cells (Tregs)

Function: Suppress immune response; Role: Prevent autoimmunity; Immunity Type: Adaptive immunity

CD8⁺ Cytotoxic T Cells

Function: Kill virus-infected cells using perforin & granzymes; Role: Defense against intracellular pathogens and tumors; Immunity Type: Adaptive (cell-mediated)

Memory T Cells

Function: Long-term cellular memory; Role: Faster response on re-exposure; Immunity Type: Adaptive (cell-mediated)