Immune Responses Overview

A group of proteins in the blood that work together to destroy pathogens. They are activated in a cascade, leading to the formation of fragments of C3 and C5, which promote inflammation and phagocytosis.

Proteins that are activated when they bind to specific molecules on microbial surfaces. They initiate the alternative and lectin pathways of complement activation.

The process by which microbes are engulfed and destroyed by phagocytes. This is a key function of innate immunity.

Specialized immune cells that engulf and destroy pathogens. Examples include neutrophils and macrophages.

A type of immune cell that is abundant in the blood and is the first line of defense against infection.

A type of immune cell that resides in tissues and is involved in both innate and adaptive immunity. They are effective phagocytes and also produce cytokines.

Small signaling molecules that are produced by cells of the immune system. They help to regulate immune responses, such as inflammation.

A type of cytokine that is produced by macrophages, DCs, and other innate immune cells. It induces inflammation and helps to recruit other immune cells to the site of infection.

Immune system cells that recognize and engulf pathogens, triggering the adaptive immune response.

Cytokines secreted by APCs that activate and differentiate T cells into effector T cells, enhancing their function.

Complement fragments, part of the innate immune system, that act as second signals for B cell activation and antibody production.

A key regulatory cytokine that inhibits the activation of macrophages and DCs, preventing excessive inflammation.

They are glycoproteins produced by B lymphocytes, consisting of two heavy chains and two light chains, forming the basic antibody structure.

Antibodies serve as receptors on B cells, triggering activation upon antigen binding.

They neutralize microbes and toxins, and engage effector mechanisms to eliminate antigens, providing humoral immunity.

These regions within the antibody molecule are highly variable, allowing for millions of different antibodies with distinct antigen specificities.

MHC molecules present peptides to T cells, with class I MHC presenting peptides to CD8+ T cells and class II MHC presenting to CD4+ T cells.

MHC molecules bind only one peptide at a time, but they can bind multiple peptides with similar structural features.

MHC molecules have specific pockets that interact with complementary residues on the peptide.

The peptide-binding cleft of Class I MHC is smaller than Class II MHC, allowing Class I to bind shorter peptides and Class II to bind longer peptides.

Class I MHC is expressed on all nucleated cells, while Class II MHC is mainly expressed on antigen presenting cells (APCs).

The process of converting native proteins into MHC-associated peptides for presentation to T cells.

For Class I MHC, proteins are degraded in the proteasome, generating peptides that are transported to the ER via TAP and bind to MHC.

Both extracellular and intracellular proteins can be sampled by antigen processing pathways, allowing for surveillance of both self and foreign proteins.

A process where specialized antigen-presenting cells (APCs), primarily dendritic cells (DCs), engulf virus-infected or tumor cells, and transport their antigens into the cytosol for presentation by MHC class I molecules.

A protein complex within the endoplasmic reticulum (ER) that helps load peptides onto newly synthesized MHC class I molecules.

A small peptide remnant of the invariant chain (Ii) that initially occupies the peptide-binding cleft of MHC class II molecules. It must be removed by DM molecules before antigen peptides can bind.

A molecule that facilitates the exchange of CLIP with antigenic peptides in the MHC class II pathway. It is crucial for antigen presentation by MHC class II.

Molecules that act as 'signposts' on the cell surface, displaying fragments of proteins (peptides) from within the cell to T cells.

A class of T cells that recognizes antigens presented by MHC class I molecules and targets infected cells for destruction.

A class of T cells that recognizes antigens presented by MHC class II molecules and helps activate other immune cells to fight infections.

A rapid immune response triggered by allergens that involves mast cells, basophils, and the release of histamine and other inflammatory mediators.

A severe, life-threatening allergic reaction characterized by widespread vasodilation, vascular leakage, airway obstruction, and reduced blood volume.

Chronic inflammatory airway disease characterized by bronchial inflammation and episodes of reversible bronchoconstriction, often triggered by allergens.

Inflammation of the nasal mucosa caused by allergens, often resulting in sneezing, runny nose, and itchy eyes.

A delayed immune response that occurs several hours after an initial exposure to an allergen. It is characterized by an influx of neutrophils and eosinophils.

Inherited predisposition to develop allergic diseases, involving variations in specific genes that influence immune responses.

Treatment involving controlled exposure to allergens with the aim of reducing the body's allergic response by potentially suppressing Th2 cell activity and decreasing allergen-specific IgE production.

A type of medication used to manage allergic diseases that targets cytokines, their receptors, or IgE.

The process where a cell's DNA is rearranged to create unique antibody or TCR genes, leading to a vast diversity of immune receptors.

Early B cell precursors that haven't undergone Ig gene rearrangement. They have the original, germline configuration of their Ig genes.

The transition from pro-B to pre-B cells involves the completion of V-D-J recombination at the Ig heavy chain locus. This generates a mature mRNA, which is translated into the µ heavy chain protein.

A receptor formed by pairing the µ heavy chain with surrogate light chains. It helps signal for survival and proliferation, ensuring only productive clones survive.

The process where a B cell's genes are modified to remove self-reactive antibodies. If successful, the B cell differentiates into a mature B cell.

The process where thymocytes, the immature T cells, undergo TCR gene rearrangement and express CD3, TCR, CD4, and CD8 molecules. This occurs in the outer cortex of the thymus.

A stage where the thymocyte completes V-D-J recombination at the TCR β chain locus, resulting in the production of TCR β chain polypeptides.

Cells that express both CD4 & CD8 coreceptor molecules. These cells undergo further selection and differentiation in the thymus.