Liposomes derived from Mycobacterium smegmatis promote immune activation of mice bone marrow-derived dendritic cells.

Background: Tuberculosis (TB) is the leading cause of mortality due to infectious diseases. The development of new generation vaccines against TB is of paramount importance for the control of the disease. In previous studies, liposomes obtained from lipids of Mycobacterium smegmatis (LMs) demonstrated their immunogenicity and protective capacity against Mycobacterium tuberculosis in mice. To characterize the immunomodulatory capacity of this experimental vaccine candidate, in the current study, the stimulatory capacity of LMs was determined on bone marrow-derived dendritic cells (BMDCs) from mice. Methods: LMs were obtained and incubated with mature BMDCs. The internalization of LMs by BMDCs was studied by confocal microscopy, and the LMs immune-stimulatory capacity was determined by the expression of surface molecules (CD86 and MHCII) and the cytokine production (interleukin [IL]-12, interferon-Υ, tumor necrosis factor-α, and IL-10) 24 h after exposure to LMs. Results: The interaction of LMs with BMDCs and its internalization was demonstrated as well as the immune activation of BMDCs, characterized by the increased expression of CD86 and the production of IL-12. The LMs internalization and immune activation of BMDCs were blocked in the presence of cytochalasin, filipin III and chlorpromazine, which demonstrated that internalization of LMs by BMDCs is a key process for the LMs induced immune activation of BMDCs. Conclusions: The results obtained support the further evaluation of LMs as a mycobacterial vaccine, adjuvant, and in immunotherapy.

Mycobacterium smegmatis proteoliposome induce protection in a murine progressive pulmonary tuberculosis model.

Tuberculosis (TB) remains an important cause of mortality and morbidity. The TB vaccine, BCG, is not fully protective against the adult form of the disease and is unable to prevent its transmission although it is still useful against severe childhood TB. Hence, the search for new vaccines is of great interest. In a previous study, we have shown that proteoliposomes obtained from Mycobacterium smegmatis (PLMs) induced cross reactive humoral and cellular response against Mycobacterium tuberculosis (Mtb) antigens. With the objective to evaluate the protective capability of PLMs, a murine model of progressive pulmonary TB was used. Animals immunized with PLMs with and without alum (PLMs/PLMsAL respectively) showed protection compared to non-immunized animals. Mice immunized with PLMsAL induced similar protection as that of BCG. Animals immunized with BCG, PLMs and PLMsAL showed a significant decrease in tissue damage (percentage of pneumonic area/lung) compared to non-immunized animals, with a more prominent effect in BCG vaccinated mice. The protective effect of the administration of PLMs in mice supports its future evaluation as experimental vaccine candidate against Mtb.

A novel monoclonal antibody to Neisseria meningitidis serogroup X capsular polysaccharide and its potential use in quantitation of meningococcal vaccines.

A novel murine hybridoma monoclonal antibody (MAb) was produced against the capsular polysaccharide (CP) of Neisseria meningitidis serogroup X (MenX) in order to develop a sandwich enzyme linked immunosorbent assay (ELISA) for the quantitation of the meningococcal polysaccharide. The MAb only reacted with the CP from MenX and did not react with CPs from N. meningitidis serogroups A, C, Y and W (MenA, MenC, MenY, MenW). The affinity constant (Ka) of the MAb measured by non-competitive ELISA was 7.25 × 10(7) M(-1). The application of this MAb in a sandwich ELISA was demonstrated by its ability to properly quantitate three lots of an experimental meningococcal CP-based vaccine. The MAb obtained in this work could be a valuable reagent for the detection and quantitation of future meningococcal vaccines containing MenX CP.

Mucosal and systemic immune responses of mice to tetanus toxoid coadministered nasally with AFCo1.

Mucosal immune responses are an early and important line of defense against pathogens. The current understanding of the mucosal immune system allows us to consider the use of nasal immunization for induction of antigen-specific immune responses at the mucosal surface and the systemic compartment. Mucosal adjuvants are key for developing novel mucosal vaccines and represent 1 approach to improving mucosal and systemic immunity. However, few mucosal vaccine adjuvants are currently approved for human use. Neisseria meningitidis B proteoliposome-derived cochleate (AFCo1 - Adjuvant Finlay Cochleate 1) has been demonstrated to be a potent mucosal adjuvant. The present work demonstrates that intranasal immunization of 3 doses of tetanus toxoid (TT) coadministered with AFCo1 in mice promotes high systemic and mucosal responses. The anti-TT IgG serum titers and the mucosal anti-TT IgA in saliva and vaginal wash were significantly higher than TT alone. The analysis of antibody subclasses showed that intranasal administration of AFCo1 + TT induced not only IgG1 but also IgG2a anti-TT antibodies at levels comparable to those obtained with TT vaccine (vax-TET). These data support the fact that AFCo1 is a potent mucosal adjuvant in nasal immunization to a coadministered protein antigen.

Inmunización intranasal con AFCo1 induce respuesta inmune de memoria, sistemica y mucosal en ratones neonatal

Neonates have a poorly developed immune system. Respiratory pathogens cause disease during early periods of live. Consequently, it is important to develop protective vaccines that induce immunity and immunological memory against respiratory pathogens early in life. Intranasal (i.n.) route could be an effective via for immunization. Therefore, we explored the effectiveness of AF (Adjuvant Finlay) PL1 (Proteoliposome) from Neisseria meningitidis serogroup B and its derivate Cochleate (AFCo1) by nasal route in neonatal mice. They were immunized i,n, 3 times 7 days apart and anti PL systemic and mucosal antibody response were measured by ELISA. In addition, a prime-boost strategy was used to evaluate the humoral immune response in neonate mice. The 3 doses of AFPL1 or AFCo1 induced significant levels of anti PL IgG antibodies in comparison whit control, but AFCo1 (2017 U/mL) was significantly higher than AFPL1 (1107 U/mL). AFCo1 and AFPL1 induced a predominant Th1 pattern with IgG2a/IgG1 >1 by i,n, immunization and AFCo1 induced a high anti PL IgA saliva response in saliva. Interestingly, one nasally prime at 7 days of born and a memory one boost i,n, dose 9 weeks later with AFCo1 or AFPL1 showed similar specific IgG levels and IgG2a/IgG1 relation than 3 i.n. doses in adult mice. In conclusion, these results represent the first report of neonatal intranasal vaccination using AFCo1 capable to induce systemic and mucosal immunity and priming for memory(AU)

Ensayo de inmunogenicidad y toxicidad local del cocleato de Neisseriameningitidis en ratas Sprague Dawley / Study of immunogenicity and local toxicity of the Neisseria meningitidis cochleate in Sprague Dawley rats

Los estudios de tolerancia local para productos vacunales resultan fundamentales como requisitos regulatorios para los estudios preclínicos. En este ensayo se utilizaron 48 ratas Sprague Dawley, de ambos sexos, con un peso corporal de 180-220 g, suministradas por el Centro Nacional para la Producción de Animales de Laboratorio, y una duración de 17 días. Las ratas fueron distribuidas en 5 grupos: 3 con diferentes concentraciones de cocleatos, uno sin inocular y otro que recibió el diluente del producto en prueba. A estas se les realizaron las observaciones clínicas necesarias, tales como: mediciones de incremento de peso, consumo de alimentos y agua, así como la evaluación anatomopatológica en los dos tiempos de sacrificio, uno a los 12 y otro a los 17 días; se enfatizó en el estudio histopatológico de encéfalo y las fosas nasales en tres niveles de su extensión. Se hicieron investigaciones inmunológicas consistentes en la determinación de IgG en suero, saliva y líquido cefalorraquídeo. Los resultados arrojaron un incremento del peso. En el consumo de agua y alimento no se observaron alteraciones clínicas, la anatomopatología evidenció discretos cambios inflamatorios que guardaron una relación directa con el aumento de las concentraciones del producto, los títulos de IgG en la saliva y suero de las ratas inoculadas con los cocleatos difirieron de forma significativa (P < 0,05) respecto a los grupos controles, el líquido cefalorraquídeo resultó negativo a la presencia de anticuerpos específicos IgG. Se concluye que los cocleatos aplicados por esta vía en ratas resultaron inmunogénicos e inocuos para el referido producto(AU)

Local Tolerance studies for vaccine products are a main link in the chain of Regulatory Requirements for toxicological preclinical studies. Mainly considering that the use of mucosal road seems to be a current tendency due to the advantages it offers. Sprague Dawley rats of both sexes weighing 100-120 g (reception weight) provided by CENPALAB with the corresponding certificates of sanitary and genetic quality were used in this test. Local tolerance study lasted 17 days. Rats were distributed in 5 groups (3 groups with different cochleate concentrations, one without inoculation and another one that received the diluents of the product in test. Measurement of weight increase, food and water consumption, as well as the anatomopathologic studies in the two times of sacrifice, at 12 and 17 days were performed. Main histopathological studies were carried out in brain and nasal nostrils in three levels of their extension (anterior, medium and posterior areas). In addition, immunological assays such as the determination of IgG in serum, saliva and cerebrospinal fluid (CSF) were carried out. Results showed a sustained weight increase. There were no clinical alterations during water and food consumption, while the existence of discreet acute inflammatory changes was found by anatomopathological studies, which were directly related to the increase of the product concentration. The presence of IgG antibodies in saliva and in sera of the rats inoculated with the cochleates showed significant differences (P <0.05) compared to the non inoculated control group and to the animals inoculated with the diluent. CSF studies resulted negative regarding the presence of specific IgG antibodies. The existence of a direct relation among the concentrations of the product in test and the inflammatory processes in the medium and posterior levels of the nasal nostril was proven, therefore it is considered that cochleates applied by this route and in the concentrations ...(AU)

Cuantificación de lipopolisacárido en un proteoliposoma obtenido a partir de la superficie externa de Vibrio cholerae O1 / Lipopolysaccharide quantification in a proteoliposome obtained from external surface of Vibrio

El lipopolisacárido (LPS) de Vibrio cholerae O1, a diferencia de la mayoría de las bacterias gramnegativas, no es reactivo en el ensayo del KDO, un método ampliamente utilizado para la cuantificación de LPS. Este LPS puede ser cuantificado por peso seco cuando se trata del antígeno en estado puro, pero cuando se necesita cuantificarlo, por ejemplo en un proteoliposoma, se requieren métodos de hidrólisis fuerte para que la molécula de KDO se exponga y sea reactiva en el ensayo antes mencionado. En este trabajo describimos un método rápido, sencillo y reproducible que nos permite cuantificar el LPS en un proteoliposoma obtenido a partir de la superficie externa de V. cholerae O1, El Tor Ogawa, mediante el uso de un anticuerpo monoclonal anti-LPS Ogawa en Western blot y la posterior evaluación del perfil reactivo en un densitómetro, utilizando LPS Ogawa purificado y cuantificado por peso seco como patrón de referencia. Este método puede ser aplicado a cualquier otra preparación que contenga LPS y que no pueda ser evaluada por KDO(AU)