Editing DNA vaccine (section)

=== Antigen presentation by bone marrow-derived cells ===

[[Image:Dendritic cell.JPG|thumb|right|A dendritic cell]]

Studies using [[Chimera (genetics)|chimeric]] mice have shown that antigen is presented by bone-marrow derived cells, which include dendritic cells, macrophages and specialised [[B-cells]] called professional [[antigen presenting cells]] (APC).<ref name=Iwasaki1997 /><ref name=Corr1996>{{cite journal | vauthors = Corr M, Lee DJ, Carson DA, Tighe H | title = Gene vaccination with naked plasmid DNA: mechanism of CTL priming | journal = The Journal of Experimental Medicine | volume = 184 | issue = 4 | pages = 1555–1560 | date = October 1996 | pmid = 8879229 | pmc = 2192808 | doi = 10.1084/jem.184.4.1555 }}</ref> After gene gun inoculation to the skin, transfected [[Langerhans cell]]s migrate to the draining [[lymph node]] to present antigens.<ref name=Robinson2000 /> After IM and ID injections, dendritic cells present antigen in the draining lymph node<ref name=Casares1997 /> and transfected macrophages have been found in the peripheral blood.<ref name=Chattergoon1998>{{cite journal | vauthors = Chattergoon MA, Robinson TM, Boyer JD, Weiner DB | title = Specific immune induction following DNA-based immunization through in vivo transfection and activation of macrophages/antigen-presenting cells | journal = Journal of Immunology | volume = 160 | issue = 12 | pages = 5707–5718 | date = June 1998 | doi = 10.4049/jimmunol.160.12.5707 | pmid = 9637479 | s2cid = 33499198 | url = http://www.jimmunol.org/cgi/content/abstract/160/12/5707 | doi-access = free }}</ref>

Besides direct transfection of dendritic cells or macrophages, cross priming occurs following IM, ID and gene gun DNA deliveries. Cross-priming occurs when a bone marrow-derived cell presents peptides from proteins synthesised in another cell in the context of MHC class 1. This can prime cytotoxic T-cell responses and seems to be important for a full primary immune response.<ref name=Robinson2000 /><ref name=Torres1997>{{cite journal | vauthors = Torres CA, Iwasaki A, Barber BH, Robinson HL | title = Differential dependence on target site tissue for gene gun and intramuscular DNA immunizations | journal = Journal of Immunology | volume = 158 | issue = 10 | pages = 4529–4532 | date = May 1997 | doi = 10.4049/jimmunol.158.10.4529 | pmid = 9144463 | s2cid = 45069087 | url = http://www.jimmunol.org/cgi/pmidlookup?view=long&pmid=9144463 | doi-access = free }}</ref>