Remote induction of cellular immune response in mice by anti-meningococcal nanocochleates - nanoproteoliposomes

Abstract

New adjuvant formulations, based on proteoliposomes <40 nm and cochleates <100 nm, without Al(OH) 3 adjuvant, were evaluated regarding their ability to generate Th1 immune response through a Delayed -Type Hypersensitivity Test, at the mouse model, by using a Neisseria meningitidis B protein complex as antigen. The formulations were administered by intramuscular (IM) (2 inoculations -at baseline and after 14 days) and intranasal (IN) (3 inoculations at 7 days) immunization pathways. All IM immunized groups were able to induce similar response to these formulations as well as to VA-MENGOC-BC® vaccinecontaining Al(OH) 3 adjuvant (used as positive control of the trial). In all groups, the induced inflammation (IP) rate was statistically higher than in the negative control group (CN) (p<0.05). Immunogenicity, measured by HSR and CD4 + lymphocyte increase was equivalent to the control vaccine and most important, granuloma reactogenicity at the site of injection was eliminated, fact demonstrated by histological study. All groups of animals immunized by IN route showed HSR reactions and statistically significant differences with respect to the CN group. However, IP values were lower, with statistical differences (p<0.05) for the same adjuvant formulation IM administered, except the AIF2-nCh formulation that generated statistically similar induction (p>0.05) by both immunization pathways, suggesting it to be the best candidate for the next IN trial. Proteoliposome and cochleate formulations tested were able to mount potent Th-1 immune response, equivalent to the original vaccine formulation, with the advantage of less reactogenicity in the site of the injection, caused by the toxicity of Al(OH) 3 adjuvant gel.

Immuno-toxicological Evaluation of the Adjuvant Formulations for Experimental Anti-meningococcal Vaccines without Aluminium Hydroxide

“…It was also included a negative control group (NC), to which a PBS was administered. The same schemes of immunization was used in one of our previous study [6].…”

“…The mice were cared according to the guidelines established by the Guide for the Care and Use of Laboratory Animal, 2010, and the institutional regulations of the National Centre of Bioproducts (BIOCEN), with the permission and complete Experimental Protocol approval of the Ethics Committee of this centre. Mice were housed in a polycarbonate cage, in a room with controlled temperature and humidity, and given food and water ad libitum [6].…”

“…Obtaining PL or vesicles, derived from the outer membrane of the N. meningitidis (NMB) serogroup, as antigenic component of the VA-MENGOC-BC® antimeningococcal vaccine, was one of the most successful approaches to the protection against disease caused by this microorganism [5,6]. PL are nanovesicles that contain lipopolysaccharides (LPS) and phospholipids, proteins of the bacterial outer membrane [5][6][7][8][9]. The immunological properties of these PL have been widely studied to demonstrate their capacity to induce Th1 immune responses [6,10,11].…”

“…PL are nanovesicles that contain lipopolysaccharides (LPS) and phospholipids, proteins of the bacterial outer membrane [5][6][7][8][9]. The immunological properties of these PL have been widely studied to demonstrate their capacity to induce Th1 immune responses [6,10,11]. The PL transformation into Ch applied to VA-MENGOC-BC® vaccine allows to increase the stability of its components preserving the pathogen associated molecular patterns (PAMPs) derived from the bacterial surface of the meningococcal B, increase the resistance to an aggressive environment as well as the interaction with the cells of the immune system [12].…”

“…Therefore, considering all the previous statements and the fact that we wanted to explore the anti-meningococcal vaccines from another point of view (immunotoxicological) than the issues already approached in our previous paper [6], in the present study have been evaluated immuno-toxicological parameters of the new adjuvant formulations with PL and Ch nanoparticles (that have been designed with immune-modulator properties). The experiments were made using the Balb/c mouse model.…”