Antigen Presentation and T Cell Stimulation by Dendritic Cells

Abstract

Dendritic cells take up antigens in peripheral tissues, process them into proteolytic peptides, and load these peptides onto major histocompatibility complex (MHC) class I and II molecules. Dendritic cells then migrate to secondary lymphoid organs and become competent to present antigens to T lymphocytes, thus initiating antigen-specific immune responses, or immunological tolerance. Antigen presentation in dendritic cells is finely regulated: antigen uptake, intracellular transport and degradation, and the traffic of MHC molecules are different in dendritic cells as compared to other antigen-presenting cells. These specializations account for dendritic cells' unique role in the initiation of immune responses and the induction of tolerance.

Neonatal exposure to staphylococcal superantigen improves induction of oral tolerance in a mouse model of airway allergy

“…Studies have shown that APC residing both in the intestinal lamina propria and in the MLN have distinct tolerogenic properties and that their antigen presenting ability favours development of Treg [44]. A tolerogenic APC lacks the complete range of co-stimulatory molecules necessary for full T-cell activation and APC with a tolerogenic potential has the capacity to present an antigen to a naïve T cell in such a manner that it is converted to a Treg [45].…”

“…Studies have shown that APC residing both in the intestinal lamina propria and in the MLN have distinct tolerogenic properties and that their antigen presenting ability favours development of Treg [44]. A tolerogenic APC lacks the complete range of co-stimulatory molecules necessary for full T-cell activation and APC with a tolerogenic potential has the capacity to present an antigen to a naïve T cell in such a manner that it is converted to a Treg [45].In conclusion, we show here that mice neonatally pretreated with S. aureus superantigen (SEA) improve their oral tolerance mechanism. Further studies are needed to dissect the involved mechanisms behind the remarkably longlasting effect of neonatal SEA administration, which act in favour of oral tolerance.…”

Early life T cell responses to pneumococcal conjugates increase with age and determine the polysaccharide‐specific antibody response and protective efficacy

“…There is substantial evidence that the professional APC, that are crucial in T cell activation, are dysfunctional early in life [47]. Naive T cells require prolonged signaling through the TCR and increased costimulation, and are thus mainly stimulated by dendritic cells (DC) of the myeloid lineage [48,49]. Several groups have demonstrated that DC from both human cord-blood [50], and neonatal mice [51] show decreased capacity of antigen presentation and stimulation of CD4 + T cells.…”

An important role of Tyk2 in APC function of dendritic cells for priming CD8+ T cells producing IFN‐γ

“…Introduction DC, one of the earliest cell types exposed to pathogens, are the most potent APC with a unique ability to induce primary immune responses against microbial infection [1][2][3]. First, immature DC capture the pathogen via high endocytic and phagocytic activities, and then they migrate to regional LN where they develop into mature DC through interaction of TLR and the microbial products, and become APC able to activate Ag-specific naive lymphocytes [4].…”