T Cell Types and Functions and their role in immunity.pptx

T_Cell_Types_and_Functions

1. Types of T Cells and Their Functions

2. T Cell Types and Functions Type of T Cell Subtypes (if any) Function Key Features Helper T Cells (CD4⁺) Th1 Activate macrophages and cytotoxic T cells to fight intracellular pathogens Secretes IFN-γ, enhances phagocytosis Th2 Stimulate B cells for antibody production, especially IgE Secretes IL-4, IL-5, IL-13; involved in allergic responses Th17 Enhances neutrophil response to fight extracellular bacteria and fungi Secretes IL-17, IL-22; linked to autoimmune diseases Tfh (Follicular Helper T Cells) Assist B cells in germinal centers for antibody production Express CXCR5, secrete IL-21 Treg (Regulatory T Cells) Suppress immune overactivation to prevent autoimmunity Secretes IL-10, TGF-β; maintains immune tolerance Cytotoxic T Cells (CD8⁺) - Kill virus-infected and cancerous cells Use perforin and granzymes to induce apoptosis Memory T Cells - Provide long-term immunity after infection Rapidly respond to previously encountered antigens Gamma Delta (γδ) T Cells - Bridge innate and adaptive immunity Recognize antigens without MHC restriction Natural Killer T Cells (NKT) - Recognize lipid antigens and regulate immune responses Share properties of T cells and NK cells