General concepts
This immunological principle explains why a second exposure to the same pathogen typically generates a faster and stronger immune response
What is immunological memory?
Antibodies are produced and secreted by these fully differentiated B lymphocytes.
What are plasma cells?
These immune cells are often the first responders to infection and are specialized in phagocytosing bacteria.
What are neutrophils?
This process generates enormous diversity in antigen receptors by rearranging gene segments in B and T cells.
What is somatic recombination?
This scientist is famous for developing the first successful vaccine against rabies in 1885.
Who is Louis Pasteur?
This type of immunity develops after exposure to a pathogen or vaccination and involves immunological memory.
When enzymatically digested, this region of antibodies is responsible for antigen recognition
What is the Fab fragment?
These germline-encoded receptors recognize conserved pathogen structures such as lipopolysaccharide and viral RNA.
What are pattern-recognition receptors?
These enzymes initiate V(D)J recombination by introducing double-strand DNA breaks at recombination signal sequences.
What are RAG1/RAG2?
This lymphoid organ, often removed in patients with abdominal trauma, plays a major role in filtering blood-borne pathogens.
What is the spleen?
These category of immune cells present processed antigen fragments on MHC molecules to activate T lymphocytes.
What are Antigen Presenting Cells (APCs)?
This antibody isotype is the most abundant in human serum and is the main antibody involved in secondary immune responses.
What is IgG?
This family of receptors includes 10 members in humans; it plays a central role in detecting pathogens in innate immunity.
What are TLRs?
This is the first chain to rearrange in cells undergoing B-cell development.
This technology, awarded the 2018 Nobel Prize in Chemistry, allows rapid evolution of proteins such as antibodies in the laboratory.
What is phage display?
This class of molecules is present in all nucleated cells, and is in charge of presents endogenous intracellular peptides to CD8⁺ cytotoxic T cells.
What is MHC class I?
This antibody isotype forms pentamers and is usually the first antibody produced during a primary immune response.
What is IgM?
What is the alternative complement system?
This enzyme adds non-templated nucleotides at junctions during V(D)J recombination, increasing receptor diversity.
What is TdT?
Fundamental discoveries in this immune process granted the 2025 Nobel prize to Mary Brunkow, Fred Ramsdell and Shimon Sakaguchi.
What is peripheral immune tolerance?
This term describes the immune system’s ability to distinguish between the body’s own molecules and foreign molecules.
What is self-tolerance?
This process changes the antibody isotype (for example from IgM to IgG or IgA) without altering antigen specificity.
These innate lymphocytes kill virus-infected or tumor cells but they are part of our innate immunity branch.
What are NK cells?
In addition to combinatorial diversity, this genetic rearrangement process explains how the immune system can generate billions of unique antigen receptors from a limited number of genes.
What is junctional diversity?
Genetic defects in these genes impair V(D)J recombination and can lead to severe combined immunodeficiency.
What are RAG1/2 genes?