Immunology Lesson 4 Quiz

A series of protein activations that leads to pathogen destruction, limited by control proteins.

Proteins that regulate the activation cascade, preventing excessive or widespread activation.

A component of the classical complement pathway; binds antibodies to initiate the cascade.

Six globular heads, requiring two antibodies for activation, preventing inappropriate activation and ensures sufficient antibody levels.

Proteolytic enzymes activated by C1q; they cleave the subsequent complement components (C4 and C2).

Complement components cleaved by activated C1r and C1s, forming C4b and C2a.

The larger fragment formed by cleaving C4; forms a bond to target.

The larger fragment of C2; associates with C4b to form C3 convertase.

The enzyme formed by the combination of C4b and C2a; cleaves C3.

The splitting of C3 into C3a and C3b, with C3b being the larger fragment

Creating a membrane pore to lyse pathogens, leading to osmolarity lysis

The most abundant enzyme in the complement system, found in blood and bodily fluids. It plays a critical role in the complement cascade.

An enzyme that cleaves C3 into C3a and C3b. It's crucial for initiating the complement cascade.

C4b2a3b, an enzyme formed during the complement cascade, that cleaves C5 into C5a and C5b. This step sets the stage for the Membrane Attack Complex (MAC).

A complex of complement proteins that creates pores in the membrane of pathogen cells, leading to cell lysis (destruction).

A complement activation pathway triggered by antibodies (IgM and IgG3) bound to pathogens.

A complement activation pathway triggered by proteins (MBP and Ficolin) binding to pathogen sugars (carbohydrates).

A protein in the lectin pathway that recognizes specific sugars on pathogen surfaces and initiates complement activation.

A family of proteins in the lectin pathway for activating the complement system, similar to MBP in function, recognizing pathogen sugars.

A process where antibody-antigen complexes are cleared from the body before they trigger excessive complement activation, which could lead to damage.

C3b binds to antibodies in immune complexes, allowing their removal via red blood cells to spleen/liver for phagocytosis.

The control mechanisms that prevent excessive or runaway complement activation.

A protein that inhibits the activation of the complement's first component (C1), preventing uncontrolled activation.

A genetic condition resulting from a deficiency in C1 inhibitor, leading to uncontrolled complement activation and swelling.

The oldest complement pathway, triggered by C3 hydrolysis, leading to pathogen destruction

C3's self-cleavage exposing its thioester domain allowing the pathway to start.

Presence of a pathogen stabilizes C3b, allowing complement activation, binding to Factor B.

A complement protein that binds to C3b, crucial for activation.

Cleaves Factor B into Ba and Bb fragments activating the next steps.

Forms the short-lived C3 convertase, initiating further cleavage.

A complement protein that prolongs C3 convertase activity, formed by neutrophils.

The enzyme created by Properdin and other proteins, essential for cleaving C5 and initiating membrane attack complex.

Glicoproteins belonging to the immunoglobulin family, found on cell surfaces in vertebrates. They are crucial for presenting internal cell contents.

MHC molecules are categorized into three classes (I, II, and III). Classes I and II are vital for presenting internal cell contents; Class III plays a role in the immune response but not in presentation

Similar to classical MHC genetically, but do not participate in antigen presentation.

A cluster of genes that create MHC molecules; it's polygenic, polymorphic, and codominant.

The MHC locus contains multiple genes that code for MHC molecules.

The MHC locus has various variations (alleles) in a population for each gene, leading to unique proteins.

Both the maternal and paternal copies of MHC genes are expressed simultaneously.

Human leukocyte antigen; a specific set of MHC genes.

The process by which MHC molecules display fragments of proteins on the cell surface to stimulate the immune system.

Molecules similar to classical HLA class I, but with genes located outside the complex. They have an alpha chain, globular chain, and beta2 microglobulin.

Some non-classical molecules activate NK cells (like ULBP) or inflammation; others activate T cells and show bacterial lipids.

The CD1 complex activates gamma delta T cells and other cells, recognizing bacterial lipids.

FCRn (neonatal Fc receptor) transports maternal immunoglobulins to the fetus.

C1 molecules contain alpha chains and beta2-microglobulin, binding glycolipids.

C1 complex activates non-classical T cells (alpha-beta), dendritic cells and macrophages, like classical HLA class I.

Heterodimer composed of alpha and beta chains with a transmembrane and short cytoplasmic domain.