Blood Composition and Key Parameters

Rearrangement of the immunoglobulin gene segments, a critical step in B cell development. If successful, the cell survives and progresses to the Pre-B cell stage. Failure results in apoptosis.

The enzyme that catalyzes the recombination of immunoglobulin gene segments in the Pro-B cell. It's crucial for generating the diverse antibody repertoire.

A protein that ensures B cell commitment, promoting the development of B cells and suppressing other cell lineages.

A checkpoint during Pre-B cell development. This receptor, comprised of a surrogate light chain and a heavy chain, assesses if the newly assembled heavy chain is functional. It's essential for cell survival.

The process of rearranging the light chain immunoglobulin gene segments in Pre-B cells. This occurs after the heavy chain has successfully assembled and provides a chance to create a functional antibody by combining both chains.

A genetic disorder where a defect in the Bruton's Tyrosine Kinase (Btk) protein prevents Pre-B cells from maturing. This results in an inability to produce antibodies.

The process where immature B cells are tested against self-antigens within the bone marrow. It ensures B cells don't produce antibodies against the body's own tissues.

B cells that encounter self-antigens in the periphery and become unresponsive, thereby preventing autoimmunity. These cells are characterized by high IgD expression and a short lifespan.

The process of generating a diverse and specific repertoire of antigen receptors by rearranging gene segments during lymphocyte development.

The key enzyme complex responsible for cutting and joining DNA segments during V(D)J recombination, specifically the RAG-1 and RAG-2 proteins.

The specific DNA sequences that flank the variable, diversity, and joining gene segments, guiding the RAG enzymes during recombination.

This enzyme adds random nucleotides to the ends of the cut DNA fragments during V(D)J recombination, further increasing diversity.

A type of T cell that recognizes antigens presented by MHC class II molecules and helps activate other immune cells.

A type of T cell that recognizes antigens presented by MHC class I molecules, and directly kills infected or cancerous cells.

A specialized type of immune cell (like dendritic cells, macrophages, and B cells) that captures and processes antigens, presenting them to T cells to initiate an immune response.

A specialized compartment within cells where proteins are broken down into smaller peptides, preparing them for MHC presentation.

Specialized cells that engulf and destroy pathogens and cellular debris. They can also present antigens to T cells, initiating an immune response.

WBCs that produce antibodies, which specifically target and neutralize pathogens. They are crucial for humoral immunity.

A group of genes responsible for encoding proteins that present antigens to T cells. They are highly diverse, ensuring a wide range of immune responses.

The process by which T cells learn to distinguish between self and non-self antigens in the thymus.

A type of T cell that is restricted to recognizing antigens presented by MHC class I molecules. They are involved in killing infected cells.

A type of T cell that is restricted to recognizing antigens presented by MHC class II molecules. They help activate other immune cells, like macrophages and B cells.

A signaling molecule produced by immune cells that can influence the activity of other cells. They are important for coordinating the immune response.

The ability of the immune system to recognize and destroy pathogens without harming the body's own cells.

An enzyme that converts cytosine to uracil in single-stranded DNA, leading to mutations during repair, primarily affecting the complementary determining regions (CDRs) of antibody genes.

The process of enhancing the affinity of antibodies for their antigen via mutations introduced by AID. It ensures antibodies become progressively more effective in binding and neutralizing their target.

A mechanism that allows B cells to switch their antibody class (e.g., IgM to IgG, IgA, or IgE) by recombining switch regions upstream of different constant region genes.

A genetic disorder caused by a deficiency in CD40 ligand, preventing B cell activation and class switching. It results in elevated IgM levels and recurrent infections.

A genetic disorder characterized by an inability to undergo somatic hypermutation and class switching, leading to low antibody affinity and diversity. It is caused by a deficiency in AID.

The regions within the variable domains of antibody genes that are particularly prone to mutations during affinity maturation. These mutations directly impact antibody-antigen binding.

Follicular lymphoma is a type of cancer that arises from B cells in the germinal centers, the sites of rapid proliferation and high mutation rates. It's one example of how uncontrolled proliferation can lead to malignancy.

A potential consequence of errors in the selection process of B cells during affinity maturation. Self-reactive B cells may escape elimination, leading to autoimmune disorders.

A subset of CD4+ T cells that primarily activate macrophages and promote the production of IgG antibodies, crucial for controlling intracellular pathogens.

A subset of CD4+ T cells that primarily drive humoral immunity, activating B cells to produce antibodies and stimulating eosinophils to combat parasites.

A subset of CD4+ T cells that promote inflammation and maintain epithelial barrier integrity, crucial for protecting against extracellular pathogens.

A subset of CD4+ T cells that help regulate B cell development and antibody production, crucial for a balanced immune response.

A subset of CD4+ T cells that suppress the activation of self-reactive T cells and promote immune tolerance, effectively preventing autoimmune responses.

The immune response upon secondary exposure to an antigen, characterized by faster activation, greater magnitude, and enhanced antibody production compared to the initial response.

Long-lived T cells that retain specificity for a particular antigen, allowing the immune system to mount a rapid and robust response upon re-exposure.

A type of memory T cell that expresses CCR7 and L-selectin, allowing them to reside in lymph nodes and readily proliferate upon antigen encounter.

A condition where B cells fail to differentiate into plasma cells or memory B cells despite expressing surface IgA.

A condition where B cells fail to mature properly, resulting in impaired immunoglobulin (Ig) production, especially of IgG, IgA, and IgM.

A severe combined immunodeficiency (SCID) that affects both T and B cell function. It's often life-threatening in infancy.

A condition caused by a deficiency or a defect in complement proteins C1, C2, or C4. This leads to decreased C3b and C4b, which are crucial for removing immune complexes.

A condition resulting from deficiencies in complement regulatory proteins (CRPs) like DAF, CD59, and HRF.

A rare inherited disorder resulting from defects in the gene responsible for anchoring complement regulatory proteins (CRPs) to cell membranes.

A genetic condition characterized by the absence or malformation of the thymus, often accompanied by other organ defects like heart, head, and neck abnormalities, and parathyroid problems.

A rare genetic disorder affecting both T and B cell function. Various causes exist, including mutations in genes for IL-2Rγ, ADA, JAK3, and other factors.