Innate Immunity
Present in tears shed during an emotional response, this enzyme breaks β-1,4 linkages between NAG and NAM in bacterial cell walls.
What is lysozyme?
Naïve mature B cells enter the primary follicle of a lymph node through this specialized vessel.
What is high endothelial valve (HEV)?
The serum concentration of this maternal immunoglobulin falls around 5 months after birth, creating a temporary window of increased susceptibility to infection.
What is IgG?
This type of cytokine is primarily produced by leukocytes?
What are interleukins?
The alternative pathway begins with this process in which C3 is spontaneously hydrolyzed to C3a and C3b before C3b can covalently bind to a microbe.
What is tickover?
During recombination of the heavy chain, template-independent N nucleotide addition occurs by this enzyme.
What is terminal-deoxynucleotide-transferase (TdT)?
These sentinels of the immune system take their job seriously and will report back to secondary lymphoid tissues to present antigen to naive T-cells.
What are dendritic cells?
A mature B cell undergoes affinity maturation that decreases the affinity of its B-cell receptor, effectively sealing this fate for the cell.
What is apoptosis?
Grab the EpiPen! Tommy has a severe peanut allergy. This cytokine stimulates class switching to the immunoglobulin isotype responsible for mast cell degranulation.
What is IL-4?
Sensitivity to environmental allergens is mediated by this vasoactive amine that is released when mast cells are degranulated.
What is histamine?
C5a is an anaphylatoxin and potent chemoattractant for these immune cells with multilobed nuclei.
What are neutophils (PMNs)?
This enzyme complex recognizes recombination signal sequences and initiates double-stranded DNA breaks during V(D)J recombination.
What is RAG1/2?
This high-affinity IgE receptor found on tissue-resident mast cells triggers rapid degranulation and release of cytokines and leukotrienes following antigen cross-linking.
What is FcεRI?
A germinal center B cell acquires a high-affinity BCR but does not induce BLIMP-1 expression. Rather than becoming a plasma cell, it is likely to differentiate into this long-lived cell type.
What is a memory B cell?
B-1 cells are primarily produced in the fetal liver and characteristically produce high levels of this surface immunoglobulin.
What is IgM?
Mutations in this intracellular protein complex can result in excessive IL-1 production and autoinflammatory disease.
What is the inflammasome?
More common in males than females, a deficiency of this protein causes susceptibility to Neisseria infections due to an inability to stabilize the C3 convertase of the alternative pathway.
What is properdin?
IL-5 and IL-6 secreted by Tfh cells induce differentiation into a CD27⁺, CD138⁺ cell that primarily resides in the innermost region of this secondary lymphoid organ.
What is a lymph node?
Inflammatory cytokines act on the hypothalamus, leading to production of this lipid mediator that causes fever by raising the body's temperature set point.
What is prostaglandin?
A specialized lymphocyte has undergone affinity maturation in a secondary follicle of the spleen and secretes IgM antibody while residing in this spleen structure.
What is the marginal zone?
Deficiency of this cytokine impairs class switching to IgA, reducing the passive mucosal immunity a mother can provide through breast milk.
What is TGF-β?
Secreted by dendritic cells and macrophage, this cytokine promotes TH1 differentiation and stimulates IFN-γ production in NK and T cells.
What is IL-12?
Recruitment and polymerization of this zymogen within the membrane attack complex forms stable transmembrane pores that promote osmotic lysis of microbes.
What is C9?
An IL-5 secreting T cell that is effective against a cestodes and is involved in allergic response belongs to this T cell subset.
What is CD4+ Th2?
Following chemokine-induced activation, LFA-1 undergoes a conformational change that allows firm adhesion through binding to this endothelial ligand.
What is ICAM-1?
IgG is a major mediator of opsonization, marking pathogens for phagocytosis through binding to this Fc receptor on phagocytes.
What is Fcγ?
Will accept FcγRI, FcγRIIA, FcγRIIC, FcγRIIIB.
During antibody-dependent cellular cytotoxicity, this NK-cell receptor binds the Fc region of IgG coating infected cells and triggers perforin and granzyme release.
What is FcγRIII (CD16)?
This cytokine interacts with GCPRs and attracts neutrophils to the site of infection by increasing integrin affinity.
What is IL-8 (CXCL8)?
To evade alternative pathway activation, Protein M of Streptococcus pyogenes recruits this complement regulatory protein that serves as a cofactor for Factor I-mediated degradation of C3b.
What is Factor H?
What is CDR/Hypervariable?
Deficiency of the gene encoding this shared β subunit of LFA-1 and Mac-1 causes Leukocyte Adhesion Deficiency Type I, characterized by recurrent infections and absent pus formation.
What is CD18?
During fetal development, this receptor facilitates transportation of IgG across the syncitiotrophoblast.
What is FcRn?
This surface immunoglobublin can be found on mature unswitched B cells but is absent from immature B cells.
What is IgD?
Besides contributing to fever, this cytokine promotes Th17 differentiation and increases neutrophil production in the bone marrow.
What is IL-6?
C1qr2s2 can be sequestered by this regulatory complement protein before binding to IgG/IgM in the classical pathway, and without it, hereditary angiodema may occur.
What is C1 INH?
A 17-year-old patient is found to have absent germinal centers and impaired class-switch recombination due to failure of AID induction. This finding suggests deficiency of this T cell-B cell costimulatory interaction.
What is CD40-CD40L?
A physician discovers that a patient with recurrent infections, partial oculocutaneous albinism, neuropathy, and bleeding has phagocytes with large lysosomes due to a lysosomal trafficking regulator protein deficiency typical of this congenital disease.
What is Chediak-Higashi Syndrome?
To transport dimeric IgA across mucosal epithelium, the polymeric immunoglobulin receptor recognizes this component of the antibody.
What is the J-chain?
A 2-month-old infant presents with recurrent pyogenic bacterial infections. Evaluation reveals deficiency of this receptor, which transports maternal immunoglobulin from breast milk across mucosal epithelium.
What is pIgR?
This pentraxin, secreted by hepatocytes, recognizes phosphatidylethanolamine on apoptotic cells and bacterial membranes.
What is serum amyloid protein (SAP)?
Immune complex-mediated nephritis can result from deficient clearance of circulating antigen-antibody complexes due to lack of this complement component that binds CR1 on erythrocytes.
What is C3b?
Following somatic hypermutation, a germinal center B cell enters the light zone where whole antigen is displayed by follicular dendritic cells. These antigen-presenting cells are derived from this multipotent stem cell type found in bone marrow.
What is mesenchymal?