Priming (immunology)
Priming is the first contact that antigen-specific T helper cell precursors have with an antigen. It is essential to the T helper cells' subsequent interaction with B cells to produce antibodies.[1] Priming of antigen-specific naive lymphocytes occurs when antigen is presented to them in immunogenic form (capable of inducing an immune response). Subsequently, the primed cells will differentiate either into effector cells or into memory cells that can mount stronger and faster response to second and upcoming immune challenges.[2] T and B cell priming occurs in the secondary lymphoid organs (lymph nodes and spleen).
Priming of naïve T cells requires dendritic cell antigen presentation. Priming of naive CD8 T cells generates cytotoxic T cells capable of directly killing pathogen-infected cells. CD4 cells develop into a diverse array of effector cell types depending on the nature of the signals they receive during priming. CD4 effector activity can include cytotoxicity, but more frequently it involves the secretion of a set of cytokines that directs the target cell to make a particular response. This activation of naive T cell is controlled by a variety of signals: recognition of antigen in the form of a peptide: MHC complex on the surface of a specialized antigen-presenting cell delivers signal 1; interaction of co-stimulatory molecules on antigen-presenting cells with receptors on T cells delivers signal 2 (one notable example includes a B7 ligand complex on antigen-presenting cells binding to the CD28 receptor on T cells); and cytokines that control differentiation into different types of effector cells deliver signal 3.[2]
Cross-priming
Cross-priming refers to the stimulation of antigen-specific CD8+ cytotoxic T lymphocytes (CTLs) by dendritic cell presenting an antigen acquired from the outside of the cell. Cross-priming is also called immunogenic cross-presentation. This mechanism is vital for priming of CTLs against viruses and tumours.[3]
Immune priming (invertebrate immunity)
Immune priming is a memory-like phenomenon described in
Mechanism of immune priming
Results of immune priming research commonly find that mechanism conferring defense against a given pathogen is dependent on the kind of insect species and microbe used for given experiment. That could be due to
Trans-generational immune priming
Trans-generational immune priming (TGIP) describes the transfer of parental immunological experience to its progeny, which may help the survival of the offspring when challenged with the same pathogen. Similar mechanism of offspring protection against pathogens has been studied for a very long time in vertebrates, where the transfer of maternal antibodies helps the newborns immune system fight an infection before its immune system can function properly on its own. In the last two decades TGIP in invertebrates was heavily studied. Evidence supporting TGIP were found in all colleopteran, crustacean, hymenopteran, orthopteran and mollusk species, but in some other species the results still remain contradictory.[10] The experimental outcome could be influenced by the procedure used for particular investigation. Some of these parameters include the infection procedure, the sex of the offspring and the parent and the developmental stage.[10]
References
- PMID 15630955.
- ^ ISBN 978-0-8153-4123-9.
- S2CID 25318142.
- PMID 30186286.
- ^ PMID 4625204.
- S2CID 3325561.
- ^ PMID 27350318.
- S2CID 86132301.
- ISBN 978-0-19-177474-4.
- ^ PMID 31475001.