Microbio Exam 3 Vocab

Epitope

Antigen determinant, the specific surface portion of an antigen recognized by the immune system—antibodies, B cells, or T cells—to trigger an immune response. Linear (contiguous amino acids) or conformational (folded 3D structures)

Major histocompatibility complex (MHC)

Polymorphic cluster of genes that encodes surface proteins responsible for presenting peptide antigens to T cells. On chromosome 6 in humans, distinguish self from non self

Endotoxin

Potent, heat stable, pro inflammatory toxin found in the outer membrane of Gram-negative bacteria. Shields bacteria from chemical attacks

Exotoxin

Potent, protein based toxin secreted by Gram-positive bacteria and some Gram-negative bacteria. Type I (superantigens), Type II (membrane-damaging toxins) and Type III (A-B toxins)

Pathogen-associated molecular pattern

(PAMP)

Small, conserved molecular motifs found on microbes (viruses, bacteria, fungi) that are recognized by the innate immune system. Act as danger signals that bind to Pattern Recognition Receptors like Toll-like receptors to trigger rapid immune responses, inflammation and pathogen elimination

Toll-like receptor (TLR)

Essential proteins in the innate immune system that act as a first line of defense, recognizing structurally conserved molecules derived from microbes (PAMPs).

Adaptive Immunity

Specialized, antigen-specific immune response mediated by both T and B lymphocytes that develops over time. Gives long-lasting protection against pathogens through immunological memory

B cell

Specialized white blood cells that are key components of the adaptive immune system. Give humoral immunity by producing pathogen-specific antibodies

Cytokine

Small signaling proteins released by immune and non immune cells that act as a chemical messenger to regulate immunity, inflammation and hematopoiesis (process of creating new blood cells)

Denitrification

Microbial mediated process that converts nitrate (NH3-) to gaseous compounds like N2 and N2O

Innate immunity

Body’s first line of defense, gives immediate, non-specific protection against pathogens from birth

Lymph

Colorless, watery fluid that contains white blood cells that circulates through the lymphatic system to maintain fluid balance, absorb fat from the intestines and remove bacteria and waste

Nitrification

Two step aerobic process that converts ammonia (NH3, NH4+) into nitrate (NO3-) via nitrite (NO2-), mainly driven by specialized bacteria in both soil and aquatic systems

Thymus

Specialized, primary lymphoid organ located in the upper chest behind the breastbone that matures T-cells to build the immune system, particularly during childhood

Vaccine

Biological preparations that give acquired immunity to infectious diseases by training the immune system to recognize and fight pathogens.