Increase of vaccines adjuvanticity by succinylation of vaccine antigen
A.V. Martynov, E.M. Babych, M.V. Smelyanskaya
Mechnicov institute of microbiology and immunology, 14-Puschinskaya St., Kharkov, 61057, Ukraine
Low adjuvanticity of vaccine antigens is one of the main problems in
development of antiviral and anticancer vaccines. This situation forces
researches to use a number of adjuvants. When Freundt adjuvant was used
with diphtherial anatoxin (as vaccine antigen) maximum titer of induced
antibodies was 1:500 at injection introducton of vaccine in accordance
with Pasteur scheme. We have developed technology for increasing
vaccine antigen adjuvanticity by 100 times at oral use of such antigen.
Technology is based on partial chemical modification of vaccine protein
antigen. Protein antigen was acylated by succinic anhydride by 3% (3 mg
of succinic anhydride with 100 mg of protein, in accordance with scheme
of professor D.K.F.Meijer). Oral introduction of such antigen to
rabbits by Pasteur scheme (1, 3, 5, 9 and 12-th days by 5 mg of 1%
solution) resulted in induction of protective antibodies against herpes
simplex virus (strain L-2, C3hc4, Ring Domain) which had titer 1:5000.
The induced antibodies protected test group of rabbits during 2 years.
Peptide mapping of complexes viral antigen+antibody indicates the
formation of antigens to absolutely new 'internal' epitopes of viral
antigens. We guess that in animal intestine incomplete hydrolysis of
modified antigen occurs to rather large peptides which are soaked up
and induce high titers of antibodies. Similar results we obtained for
diphtheria toxin (modification of 3% protein mass was followed by
inactivation by formalin), Rhinovirus 14 protein (HRV14), Influenza
Virus Hemagglutinin (2VIR). Now we obtained results which give hopes on
testing chemically modified IE1 cytomegalovirus antigen. To decrease
quantity of antigen and to check the incomplete hydrolysis hypothesis
we changed the scheme of vaccine obtaining: after 3% acylation of IE1
structure the antigen obtained was treated by enzymes immobilized on
sepharose (trypsin and papain) and then introduced by subcutaneous
injection to rabbits (in dose 1 ml of 1% solution). In 2 weeks titer of
protective antibodies in animal blood was 1:500. This fact indicates
general rule: chemical modification by acylation of 3% protein mass
results in a sharp increase of vaccine adjuvanicity that is caused by
incomplete hydrolysis of protected antigen and appearance of new unique
accessible epitopes in vaccine antigen. In our opinion, the use of
similar methods will allow to create polyvalent vaccine against many
viruses and microorganisms as well as to increase adjuvanicity of
anticancer vaccines.
Key words:
adjuvanicity, oral vaccines, succinylation, cytomegalovirus, herpes simplex virus, diphtheria toxin, rhinovirus
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