Editing DNA vaccine (section)

=== Humoral (antibody) response ===

[[Image:Antibody.svg|thumb|right|Schematic diagram of an antibody and antigens]]
Antibody responses elicited by DNA vaccinations are influenced by multiple variables, including antigen type; antigen location (i.e. intracellular vs. secreted); number, frequency and immunization dose; site and method of antigen delivery.

==== Kinetics of antibody response ====

Humoral responses after a single DNA injection can be much longer-lived than after a single injection with a recombinant protein. Antibody responses against [[hepatitis B]] virus (HBV) envelope protein (HBsAg) have been sustained for up to 74 weeks without boost, while lifelong maintenance of protective response to influenza [[haemagglutinin]] was demonstrated in mice after gene gun delivery.<ref name=Justewicz1996>{{cite journal | vauthors = Justewicz DM, Webster RG | title = Long-term maintenance of B cell immunity to influenza virus hemagglutinin in mice following DNA-based immunization | journal = Virology | volume = 224 | issue = 1 | pages = 10–17 | date = October 1996 | pmid = 8862394 | doi = 10.1006/viro.1996.0501 | doi-access = free }}</ref> Antibody-secreting cells (ASC) migrate to the [[bone marrow]] and [[spleen]] for long-term antibody production, and generally localise there after one year.<ref name=Justewicz1996 />

Comparisons of antibody responses generated by natural (viral) infection, immunization with recombinant protein and immunization with pDNA are summarised in Table 4. DNA-raised antibody responses rise much more slowly than when natural infection or recombinant protein immunization occurs. As many as 12 weeks may be required to reach peak titres in mice, although boosting can decrease the interval. This response is probably due to the low levels of antigen expressed over several weeks, which supports both {{Clarify | text = primary and secondary phases of antibody response. | date = November 2021 | reason = The terms 'secondary phase' and 'antibody response' don't even show up on google search.}} DNA vaccine expressing HBV small and middle envelope protein was injected into adults with chronic hepatitis. The vaccine resulted in specific interferon gamma cell production. Also specific T-cells for middle envelop proteins antigens were developed. The immune response of the patients was not robust enough to control HBV infection<ref>{{cite journal | vauthors = Mancini-Bourgine M, Fontaine H, Bréchot C, Pol S, Michel ML | title = Immunogenicity of a hepatitis B DNA vaccine administered to chronic HBV carriers | journal = Vaccine | volume = 24 | issue = 21 | pages = 4482–4489 | date = May 2006 | pmid = 16310901 | doi = 10.1016/j.vaccine.2005.08.013 }}</ref>

{| class="wikitable"
|+ Table 4. Comparison of T-dependent antibody responses raise by DNA immunisations, protein inoculations and viral infections
! rowspan=2| &nbsp;

! colspan=3| Method of Immunization
|-
! DNA vaccine
! Recombinant protein
! Natural infection
|-
! Amount of inducing antigen
| ng
| μg
| ? (ng-μg)
|-
! Duration of antigen presentation
| several weeks
| < 1 week
| several weeks
|-
! Kinetics of antibody response
| slow rise
| rapid rise
| rapid rise
|-
! Number of inoculations to obtain high [[avidity]] [[IgG]] and migration of {{abbr |ASC| antigen-secreting cell }} to bone marrow
| one
| two
| one
|-
! Ab isotype (murine models)
| C’-dependent or C’-independent
| C’-dependent
| C’-independent
|}

Additionally, the titres of specific antibodies raised by DNA vaccination are lower than those obtained after vaccination with a recombinant protein. However, DNA immunization-induced antibodies show greater affinity to [[Native state|native]] epitopes than recombinant protein-induced antibodies. In other words, DNA immunization induces a qualitatively superior response. Antibodies can be induced after one vaccination with DNA, whereas recombinant protein vaccinations generally require a boost. DNA immunization can be used to bias the TH profile of the immune response and thus the antibody isotype, which is not possible with either natural infection or recombinant protein immunization. Antibody responses generated by DNA are useful as a preparative tool. For example, polyclonal and monoclonal antibodies can be generated for use as reagents.{{Citation needed | date = October 2021 | reason = These last two statements probably need a citation or need clarification.}}