Block Copolymers Have Differing Adjuvant Effects on the Primary Immune Response Elicited by Genetic Immunization and on Further Induced Allergy

Abstract

Block copolymers were recently used to promote gene delivery in various tissues. Using a plasmid encoding a food allergen, bovine ␤-lactoglobulin (BLG), we studied the effects of block copolymers on gene expression levels and primary immune response and on further induced allergy. Block copolymers (i.e., Tetronic 304, 908, and 1107) and various quantities of DNA were injected into the tibialis muscles of BALB/c mice. The BLG levels in injected muscle and the BLG-specific induced immune response were analyzed after injection. DNA-immunized mice were further experimentally sensitized with BLG, and the effects of block copolymer and DNA doses on allergic sensitization and elicitation were compared. We previously demonstrated that DNA immunization using the ␤-lactoglobulin (BLG) gene, one of the major cow's milk allergens, elicited a Th1-specific immune response that inhibited Th2 cell induction and prevented further allergic sensitization (2). This approach has also been successfully applied to allergens from pollen, latex, and peanut (for a review, see reference 23). However, patients with cow's milk allergy are predominantly multisensitized, i.e., they produce IgE directed against more than one cow's milk protein (22). Moreover, many allergic patients are polyallergic, i.e., they are allergic to various allergens (food, pollen, and dust). Putative use of DNA delivery in allergy would therefore imply multigene immunization, i.e., the administration of a pool of plasmids containing the cDNAs of different allergens. This suggests that decreasing quantities of DNA should be used to determine the minimal quantity of plasmid necessary to decrease the IgE level after sensitization. In this context, adjuvants such as block copolymers, which promote the expression of various reporter genes, e.g., luciferase and ␤-galactosidase genes (11,12,16), are of interest.Block copolymers are synthesized using propylene oxide (PO) and ethylene oxide (EO), which are organized as "blocks" of polyoxyethylene (POE) and polyoxypropylene (POP). These copolymers can be designed and synthesized using various amounts of PO and EO and with differential arrangements of POP and POE blocks. Block copolymers are used for their adjuvant capacities (for a review, see reference 21) and were recently found to promote gene delivery in tissues, such as skeletal and cardiac muscle (11,(15)(16)(17)(18), lung (8), and eyes (12). Copolymers can be used to increase the intensity and/or duration of the expression of reporter genes, such as those encoding green fluorescent protein (GFP) or luciferase, but also of therapeutic genes, such as those encoding erythropoietin or dystrophin. We used poloxamine block copolymers, which have a tetrafunctional structure consisting of four PEO/ POP blocks centered on an ethylenediamine moiety (15). The DNA delivery efficiencies of 3 nonionic block copolymers, i.e., Tetronic 304, 908, and 1107, with molecular masses ranging from 1,650 to 25,000 Da, were studied by monitoring in situ protein production at different time poin...

Effect of polyoxyethylene and polyoxypropylene nonionic block copolymers on performance and recruitment of immune cell subsets in weaned pigs

“…However, depending on the quantity of POE in the copolymers they may also stimulate cellular immunity [14]. Recently, the copolymers synthesized using various amonts of POE and POP and with different arrangements of their blocks elicited different immune responses, which were always Th1 specific in mice [21]. …”

“…The production of specific anti-F4ac secretory IgA antibodies was increased in weaned pigs primed with POE-POP before the immunization with vaccine candidate F4ac + non-ETEC strain [20]. However, before the use of these copolymers synthesized using various amonts of POE and POP and with different arrangements of their blocks in animals and humans, their adjuvaticity and differing effects on the immune response have to be fully evaluated [21]. …”

Block Copolymer/DNA Vaccination Induces a Strong Allergen-Specific Local Response in a Mouse Model of House Dust Mite Asthma

“…The tetrafunctional block copolymer 704 used here is able to promote low-dose DNA vaccination efficiency without any detectable deleterious effect and was chosen for its clear efficiency in inducing a specific response [11] . Other copolymers have also been described as able to direct a more Th1/Treg biased response that could be explored in the protection against asthma in the present mouse model [19] .…”