Neisseria meningitidis B proteoliposome (AFPL1 when used as adjuvant) and its derivative-Cochleate (AFCo1) contain immunopotentiating and immunomodulating properties and delivery system capacities required for a good adjuvant. Additionally, they contain meningococcal protective antigens and permit packaging of other antigens and pathogen-associated molecular patterns (PAMP). Consequently, we hypothesized that they would function as good vaccine adjuvants for their own antigens and also for non-related antigens. AFPL1 is a detergent-extracted outer membrane vesicle of N. meningitidis B transformed into AFCo1 in calcium environment. Both are produced at Finlay Institute under good manufacture practices (GMP) conditions. We show their exceptional characteristics: combining in the same structure, the potentiator activity, polarizing agents and delivery system capacities; presenting multimeric protein copies; containing multiprotein composition and multi and synergistic PAMP components; acting with incorporated or co-administrated antigens; inducing type I IFN-gamma and IL-12 cytokines suggesting the stimulation of human plasmocytoid precursor and conventional dendritic cells, respectively, inducing a preferential Th1 immune response with TCD4(+), TCD8(+), cross-presentation and cytotoxic T-lymphocyte (CTL) in vivo responses; and functioning by parenteral and mucosal routes. AFPL1-AFCo1 protective protein constitutions permit per se their function as a vaccine. In addition to Phase IV Men BC vaccine, AFPL1 has ended the preclinical stage in an allergy vaccine and is concluding the preclinical stage of a nasal meningococcal vaccine. In conclusion, AFPL1 and AFCo1 induced signal 1, 2 and 3 polarizing to a Th1 (including CTL) response when they acted directly as vaccines or were used as adjuvants with incorporated or co-administered antigens by parenteral or mucosal routes. Both are very promising adjuvants.

Cochleate are highly stable structures with promising immunological features. Cochleate structures are usually obtaining from commercial lipids. Proteoliposome derived Cochleate are derived from an outer membrane vesicles of Neisseria meningitidis B. Previously, we obtained Cochleates using dialysis procedures. In order to increase the production process, we used a crossflow system (CFS) that allows easy scale up to obtain large batches in an aseptic environment. The raw material and solutions used in the production process are already approved for human application. This work demonstrates that CFS is very efficient process to obtain Cochleate structures with a yield of more than 80% and the immunogenicity comparable to that obtained by dialysis membrane.

Cochleate structures (CS) consist in a highly stable lipid structures that have been reported to be a good antigen delivery system. The incorporation of pathogen associated molecular pattern (PAMP) from bacterial membranes into CS became in a promising approach to develop adjuvants, particularly mucosal adjuvants. Therefore, we prepare CS from proteoliposome (PL) obtained from Neisseria meningitidis B (PLCS) and evaluated it for its capability to stimulate the immune system as well as the adjuvant activity. The ability of PLCS to induce Thl polarization was also explored. The results and the easy capability for new antigen incorporation on CS support its use as adjuvant for immunization with a large variety of pathogen derived antigens and different routes of immunization.

Proteoliposome (PL) has been recently used as a protective intramuscular (i.m.) anti-meningococcal BC vaccine. It induces a preferential Th1 type of immune response. Nevertheless, mucosal protection is mainly mediated by IgA antibody response, which is not usually induced by i.m. vaccination route. IgA antibody production needs the stimulation of Th3 subpopulation, which is also related to the induction of small dose tolerance. We hypothesized that PL-derived Cochleate can induce a specific mucosal IgA and systemic IgG antibody responses. We could show that mice immunized with two or three intranasal doses of PL-derived Cochleate developed significantly increased levels of local anti PL IgA and systemic IgG antibody responses. Thus, our results suggest that PL-derived Cochleate can be used as a promising immunomodulator and delivery system for the development of mucosal, particularly nasal vaccines.

Proteoliposomes (PL) from Neisseria meningitidis B have been widely used as a core antigen for antimeningococcal vaccination. PL contain major outer membrane proteins, LPS and phospholipids, and they induce a strong Th1 immune response, but they have low stability in solution. Attending to the need for new vaccine adjuvants, we developed a highly stable cochleate structure (CS) from PL using a technology that allows easy incorporation of new antigens. We explored the ability of PLCS to activate the immune system and its possible application as an adjuvant for parenteral and mucosal routes. Our results showed that PLCS were able to upregulate the expression of MHC class II and costimulatory molecules on human dendritic cells, as well as being able to stimulate the production of soluble mediators of a Th1 response, such as IL‐12 and nitric oxide. High levels of anti‐PL IgG were detected in serum after i.m. or mucosal (oral and nasal) administration, but also anti‐PL secretory IgA was produced in saliva following nasal delivery. The immune response polarization to a Th1 pattern was confirmed by the induction of IgG2a antibodies, positive delayed type hypersensitivity reactions, and IFN‐γ production by splenocytes from immunized mice. The adjuvant potential was explored using PLCS containing ovalbumin (Ova). PLCS‐Ova was able to elicit a substantial increase in anti‐Ova IgG compared with Ova alone. In addition, a significant reduction in lesion size was observed in mice immunized with Leishmania major antigens in PLCS after challenge with virulent protozoa, suggesting at least partial modulation of the Th2 environment induced by this parasite. In conclusion, our results support the use of PLCS as a potent Th1 adjuvant for parenteral and mucosal vaccines.

A solid-phase enzyme immunoassay (ELISA) for measuring tetanus antitoxin activity in human serum is described; the assay is based on a combination of the indirect method and ultramicro analysis. This rapid test, which has the capacity to analyze 78 blood samples per reagent plate (at a volume of 10 microL of diluted serum per sample), is proposed as an alternative to the traditional mouse bioassay system based on the neutralization of a known dose of tetanus toxin. Results from both tests showed a high correlation in the lineal regression analysis (r = 0.99; CI95%: 0.985 to 0.993). It is recommended that the ultramicro ELISA assay be used in the field to evaluate tetanus toxoid vaccines and to identify hyperimmune plasmas suitable for producing antitetanus immunoglobulin.