Freshly isolated mouse 4F7⁺ splenic dendritic cells process and present exogenous antigens to T cells

Abstract

The antibody 4F7 was reported to recognize an epitope expressed on dendritic cells (DC) from various tissues. To study the ability of splenic 4F7+ dendritic cells to process antigen for presentation to CD4+ T cells, DC were enriched using a separation procedure avoiding overnight culture which could lead to an altered phenotype. These DC were used as antigen-presenting cells (APC) in stimulation cultures of major histocompatibility complex class II-restricted T cells. It was found that they induce antigen-dependent lymphokine production by T cells and therefore could present exogenous antigens. These processing takes place intracellularly, because fixation abrogates presentation to T cells. Moreover, antigen presentation needs intracellular processing within endo- or lysosomes as chloroquine-treatment prevents T cell activation. Titration of APC numbers revealed that contaminating APC most likely did not account for antigen-specific T cell activation by DC. No evidence was found for release of antigenic peptides or for partial antigen processing possibly done by cell surface located enzymes on DC. In conclusion, these results indicate that freshly enriched DC are able to process antigens similarly to other APC.

Peptides Identified through Phage Display Direct Immunogenic Antigen to Dendritic Cells

“…Staining was decreased during the next 20 h at 37°C (Fig. 2D) consistent with Ag uptake by DC (15,22). Importantly, DC remained viable during this period.…”

“…After restriction digestion, the PCR product was inserted into compatible sites in plasmid pET24d (Novagen, Madison, WI). The forward primer encoded NS4A [21][22][23][24][25][26][27][28][29][30][31][32] peptide and thus was fused at the 5Ј end of the NS3 coding region to enhance the stability of the protein (18). To generate the final construct, the NS4A 21-32 -NS3 coding region was ligated to DNA encoding peptide 3 or control peptide, each of which was followed by a vector-encoded C-terminal histidine 6-coding sequence.…”

Comparison between the phenotype and function of maturing dendritic cells from spleen and lymph nodes

“…7 Other studies show that splenic DC cultured in vitro show up-regulation of B7 co-stimulatory molecules and develop the capacity to stimulate T-cell proliferation. 17 DC freshly isolated from spleens without culture were reported to process antigens. 17 They can stimulate T-cell proliferation of secondary responses and show increased capacity to stimulate T cells after in vitro culture.…”

“…17 DC freshly isolated from spleens without culture were reported to process antigens. 17 They can stimulate T-cell proliferation of secondary responses and show increased capacity to stimulate T cells after in vitro culture. 3,4 This effect is enhanced by the addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) during the culture period.…”

Oral Cavity-Associated Immune System: What is New?

“…They ingest antigens via several mechanisms that include phagocytosis [31] and receptor-mediated endocytosis [32]. DC internalize, process and present immunogenic peptides to various T-cell types [33,34]. The ability of DC to initiate and orchestrate immune responses is a consequence of their localization within tissues and their specialized capacity for mobilization [35].…”