Human rights and infectious diseases

This short presentation will note the lessons from human rights-based approaches to HIV for the responses to other epidemics of infectious diseases.

Mucosal and systemic immune responses induced by a single time vaccination strategy in mice

Vaccination is considered by the World Health Organization as the most cost-effective strategy for controlling infectious diseases. In spite of great successes with vaccines, many infectious diseases are still leading killers, because of the inadequate coverage of many vaccines. Several factors have been responsible: number of doses, high vaccine reactogenicity, vaccine costs, vaccination policy, among others. Contradictorily, few vaccines are of single dose and even less of mucosal administration. However, more common infections occur via mucosa, where secretory immunoglobulin A plays an essential role. As an alternative, we proposed a novel protocol of vaccination called Single Time Vaccination Strategy (SinTimVaS) by immunizing 2 priming doses at the same time: one by mucosal route and the other by parenteral route. Here, the mucosal and systemic responses induced by Finlay adjuvants (AF Proteoliposome 1 and AF Cochleate 1) implementing SinTimVaS in BALB/c mice were evaluated. One intranasal dose of AF Cochleate 1 and an intramuscular dose of AF Proteoliposome 1 adsorbed onto aluminum hydroxide, with bovine serum albumin or tetanus toxoid as model antigens, administrated at the same time, induced potent specific mucosal and systemic immune responses. Also, we demonstrated that SinTimVaS using other mucosal routes like oral and sublingual, in combination with the subcutaneous route elicits immune responses. SinTimVaS, as a new immunization strategy, could increase vaccination coverage and reduce time-cost vaccines campaigns, adding the benefits of immune response in mucosa.

Adjuvants are Key Factors for the Development of Future Vaccines: Lessons from the Finlay Adjuvant Platform

The development of effective vaccines against neglected diseases, especially those associated with poverty and social deprivation, is urgently needed. Modern vaccine technologies and a better understanding of the immune response have provided scientists with the tools for rational and safer design of subunit vaccines. Often, however, subunit vaccines do not elicit strong immune responses, highlighting the need to incorporate better adjuvants; this step therefore becomes a key factor for vaccine development. In this review we outline some key features of modern vaccinology that are linked with the development of better adjuvants. In line with the increased desire to obtain novel adjuvants for future vaccines, the Finlay Adjuvant Platform offers a novel approach for the development of new and effective adjuvants. The Finlay Adjuvants (AFs), AFPL (proteoliposome), and AFCo (cochleate), were initially designed for parenteral and mucosal applications, and constitute potent adjuvants for the induction of Th1 responses against several antigens. This review summarizes the status of the Finlay technology in producing promising adjuvants for unsolved-vaccine diseases including mucosal approaches and therapeutic vaccines. Ideas related to adjuvant classification, adjuvant selection, and their possible influence on innate recognition via multiple toll-like receptors are also discussed.

[In silico identification of molecular mimicry between T-cell epitopes of Neisseria meningitidis B and the human proteome]

The objective of the study was to determine the T-cell epitopes of four of the most frequent antigenic proteins of the outer membrane of Neisseria meningitidis B, and to identify the most relevant sites for molecular mimicry with T-cell epitopes in humans. In order to do so, an in silico study -a type of study that uses bioinformatic tools- was carried out using SWISS-PROT/TrEMBL, SYFPEITHI and FASTA databases, which helped to determine the protein sequences, CD4 and CD8 T-cell epitope prediction, as well as the molecular mimicry with humans, respectively. Molecular similarity was found in several human proteins present in different organs and tissues such as: liver, skin and epithelial tissues, brain, lymphatic system and testicles. Of these, those found in testicles were more similar, showing the highest frequency of mimetic sequences. This finding shed light on the success of N. meningitidis B to colonize human tissues and the failure of certain vaccines against this bacterium, and it even helps to explain possible autoimmune reactions associated with the infection or vaccination.

Pilot scale production of the vaccine adjuvant Proteoliposome derived Cochleates (AFCo1) from Neisseria meningitidis serogroup B

The use of new adjuvants in vaccine formulations is a subject of current research. Only few parenteral adjuvants have been licensed. We have developed a mucosal and parenteral adjuvant known as AFCo1 (Adjuvant Finlay Cochleate 1, derived from proteoliposomes of N. meningitidis B) using a dialysis procedure to produce them on lab scale. The immunogenicity of the AFCo1 produced by dialysis has been already evaluated, but it was necessary to demonstrate the feasibility of a larger-scale manufacturing process. Therefore, we used a crossflow diafiltration system (CFS) that allows easy scale up to obtain large batches in an aseptic environment. The aim of this work was to produce AFCo1 on pilot scale, while conserving the adjuvant properties. The proteoliposomes (raw material) were resuspended in a buffer containing sodium deoxycholate and were transformed into AFCo1 under the action of a calcium forming buffer. The detergent was removed from the protein solution by diafiltration to a constant volume. In this CFS, we used a hollow fiber cartridge from Amicon (polysulfona cartridge of 10 kDa porosity, 1mm channel diameter of fiber and 0.45 m² area of filtration), allowing production of a batch of up to 20 L. AFCo1 were successfully produced by tangential filtration to pilot scale. The batch passed preliminary stability tests. Nasal immunization of BALB/c mice, induced specific saliva IgA and serum IgG. The induction of Th1 responses were demonstrated by the induction of IgG2a, IFNγ and not IL-5. The adjuvant action over Neisseria (self) antigens and with co-administered (heterologous) antigens such as ovalbumin and a synthetic peptide from haemolytic Streptococcus B was also demonstrated.

Human prophylactic vaccine adjuvants and their determinant role in new vaccine formulations

Adjuvants have been considered for a long time to be an accessory and empirical component of vaccine formulations. However, accumulating evidence of their crucial role in initiating and directing the immune response has increased our awareness of the importance of adjuvant research in the past decade. Nevertheless, the importance of adjuvants still is not fully realized by many researchers working in the vaccine field, who are involved mostly in the search for better target antigens. The choice of a proper adjuvant can be determinant for obtaining the best results for a given vaccine candidate, but it is restricted due to intellectual property and know-how issues. Consequently, in most cases the selected adjuvant continues to be the aluminum salt, which has a record of safety, but predominantly constitutes a delivery system (DS). Ideally, new strategies should combine immune potentiators (IP) and DS by mixing both compounds or by obtaining structures that contain both IP and DS. In addition, the term immune polarizer has been introduced as an essential concept in the vaccine design strategies. Here, we review the theme, with emphasis on the discussion of the few licensed new adjuvants, the need for safe mucosal adjuvants and the adjuvant/immunopotentiating activity of conjugation. A summary of toxicology and regulatory issues will also be discussed, and the Finlay Adjuvant Platform is briefly summarized.

The golden era of vaccine adjuvants

A 5-day workshop on adjuvant for vaccines was held in Trinidad, Cuba, on the 16-21 May 2010. Organized by the Latin American Association for Immunology and the Cuban Society for Immunology, the workshop attracted more than 60 scientists from different parts of the world. The meeting summarizes current knowledge regarding vaccine adjuvants, including delivery systems and parasitic vaccines. Main discussion topics were the discovery of new adjuvant formulations, action mechanisms for adjuvants, adjuvants for a different route of immunization, focused on mucosal vaccines, and nano- and micro-particles as a delivery system. This article highlights the most important issues presented.

AFCo1 as nasal adjuvant of capsular polysaccharide from Neisseria meningitidis serogroup C induces systemic and mucosal immune responses

Increasing emphasis is being placed on the mucosal administration of vaccines in order to stimulate mucosal as well as systemic responses. Findings from our group suggest that proteoliposome-derived cochleate (AFCo1) acts as a potent mucosal adjuvant. As an alternative to chemical conjugation, the current study aimed to determine the benefit of using AFCo1 to improve the mucosal and systemic immune responses to capsular polysaccharide of Neisseria meningitidis serogroup C (PsC), a model of a thymus-independent (TI) antigen. Therefore, intranasal (i.n.) immunization of 3 doses 1 week apart with AFCo1 plus PsC in mice was conducted. Highly specific anti-PsC IgA responses and an anti-PsC IgG response were obtained. The subclass pattern induced against PsC was similar to that induced with the meningococcal vaccine. In summary, AFCo1 as nasal adjuvant was demonstrated to be capable of eliciting mucosal and systemic specific responses against a TI antigen.

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.

Mucosal immunization using proteoliposome and cochleate structures from Neisseria meningitidis serogroup B induce mucosal and systemic responses

Most pathogens either invade the body or establish infection in mucosal tissues and represent an enormous challenge for vaccine development by the absence of good mucosal adjuvants. A proteoliposome-derived adjuvant from Neisseria meningitidis serogroup B (AFPL1, Adjuvant Finlay Proteoliposome 1) and its derived cochleate form (Co, AFCo1) contain multiple pathogen-associated molecular patterns as immunopotentiators, and can also serve as delivery systems to elicit a Th1-type immune response. The present studies demonstrate the ability of AFPL1and AFCo1 to induce mucosal and systemic immune responses by different mucosal immunizations routes and significant adjuvant activity for antibody responses of both structures: a microparticle and a nanoparticle with a heterologous antigen. Therefore, we used female mice immunized by intragastric, intravaginal, intranasal or intramuscular routes with both structures alone or incorporated with ovalbumin (OVA). High levels of specific IgG antibody were detected in all sera and in vaginal washes, but specific IgA antibody in external secretions was only detected in mucosally immunized mice. Furthermore, antigen specific IgG1 and IgG2a isotypes were all induced. AFPL1 and AFCo1 are capable of inducing IFN-gamma responses, and chemokine secretions, like MIP-1alpha and MIP-1beta. However, AFCo1 is a better alternative to induce immune responses at mucosal level. Even when we use a heterologous antigen, the AFCo1 response was better than with AFPL1 in inducing mucosal and systemic immune responses. These results support the use of AFCo1 as a potent Th1 inducing adjuvant particularly suitable for mucosal immunization.

New Vaccines Require Potent Adjuvants like AFPL1 and AFCo1

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.

New meningococcal C polysaccharide-tetanus toxoid conjugate

The polysaccharides (Ps) are thymus-independent 2 (TI-2) antigens and poor immunogens in infants and young children; as a result of this delayed response to Ps antigens during ontogeny, infants and young children are highly susceptible to infections caused by encapsulated bacteria. Meningococcal group C polysaccharide (PsC)-proteins conjugate vaccines have been reported to induce significant serum IgG antibodies and immunologic memory in infants resulting in very effective vaccines. We describe here the obtainment, by a new method, of a neoglycoconjugate intended to immunize against Neisseria meningitidis serogroup C, its characterization by physico-chemical methods, including (1)H NMR and fluorescence spectroscopy methods, as well as the characterization of the immune response induced in mice by such conjugate. Amine groups generated by basic hydrolysis in the PsC were successfully conjugated to carboxyl groups of tetanus toxoid (TT), using carbodiimide-mediated coupling. The specific anti-Ps IgG and anti-Ps IgG subclasses (IgG1 and IgG2a) were measured by ELISA methods, the bactericidal activity in sera and the cytokines response (IFNgamma or IL5) in spleen cell of mice immunized with conjugated and native Ps were evaluated. The (1)H NMR spectra and the result obtained by the fluorescence spectroscopy method showed that the PsC and TT maintained structural identity after conjugation process. Conjugated PsC elicited an increase of anti-PsC IgG responses, anti-PsC IgG subclass (IgG1, IgG2a), an eight-fold increase in bactericidal activity in sera of mice immunized with conjugate compared with native PsC, was also observed. Higher titres of IFNgamma were observed in mice immunized with conjugated Ps. These results indicated that, the PsC and TT maintained its chemical and antigenic structure after the conjugation process. A change in the immunological pattern of responses of PsC, from TI-2 to a thymus-dependent (TD) pattern, was also demonstrated.

Preparation and evaluation of vibrio cholerae O1 EL Tor Ogawa lipopolysaccharide-tetanus toxoid conjugates

The lipopolysaccharide (LPS) of Vibrio cholerae is considered one of the most important antigens from the point of view of immunogenicity in these bacteria. We have undertaken detoxification of this LPS by basic hydrolysis and the resultant amine groups were used for their conjugation to tetanus toxoid as carrier protein using carbodiimide-mediated coupling. The resulting conjugates were inoculated in Balb/c mice for immunogenicity studies. The anti-LPS IgG and vibriocidal antibodies were measured in serum. The antigenicity of this conjugated was evaluated by ELISA, with serums of humans vaccinated with a strain genetically modified. The conjugated elicited: high titers of IgG anti-LPS, high titers of vibriocidal antibodies and there was recognition of LPS by antibodies from cholerae immunised human serum. These results show that the conjugated LPS obtained by us, could be evaluated like a potential vaccine for human use.

Adjuvant properties of lipopolysaccharide from Neisseria meningitidis serogroup B detoxified and conjugated with tetanus toxoid

We evaluated the adjuvant properties and toxicity of purified Neisseria meningitidis serogroup B lipopolysaccharide (LPS) conjugated with tetanus toxoid (TT) using a new method of conjugation to obtain amine groups in the polysaccharide structure. The endotoxic activity of treated LPS was reduced 2400 times as determined by Limulus amoebocyte assay and no mortality was observed in Balb/c mice inoculated with detoxified LPS versus 100% mortality in native LPS inoculated mice. The conjugated LPS-TT elicited in mice higher anti-TT IgG2a and IgG1 than unconjugated TT. In addition, high levels of anti-LPS IgG and IgG subclasses were detected in sera. These results evidence the adjuvant activity of detoxified LPS and may suggest that the conjugation to TT changes the LPS immune response from thymus-independent to thymus-dependent.

New method for obtaining conjugated vaccines

We describe a new method to obtain conjugates against Neisseria meningitidis serogroups A, B, C, Vibrio cholera, and Salmonella typhi and their immunogenicity in Balb/c mice. The saccharides were activated by basic hydrolysis with the generation of amine groups in the saccharidic chain, and these groups were linked to carboxyl groups of tetanus toxoid by via carbodiimida-mediated reaction. The resultant conjugates were administered to mice for the immunogenicity studies. The pirogenicity of LPS was measured by LAL assay. The anti-saccharide IgG, IgG1, and IgG2a antibodies were evaluated. A significant decrease in the pirogenicity of LPS after basic hydrolysis treatment was observed. The conjugates elicited higher titers of anti-polysaccharides or anti-LPS IgG, IgG1, and IgG2a in conjugates than in unconjugated saccharides. The results indicate that we have a new method for obtaining conjugated vaccines and we have demonstrated that after conjugation there was a change in the responses for all saccharides, from thymus-independent to thymus-dependent responses.

Mucosal immune responses to meningococcal C polysaccharide–protein conjugate in mice

Mucosal delivery of vaccines represents an attractive approach because this is a region of first contact point for inhaled antigens. We have obtained a meningococcal group C polysaccharide-tetanus toxoid conjugate (MGCP-TT) and evaluated it for intranasal route in mice. The conjugate was obtained by a developed method in our laboratory. The specific IgA in saliva and specific IgA and IgG in serum were measured by ELISA methods and bactericidal antibodies in sera against a meningococcal group C strain were measured. The conjugated elicited a significant increase in anti-MGCP salivary IgA and serum IgG and bactericidal antibodies concentrations, while specific serum IgA was not observed. These results indicated that after conjugation, there was a change in the responses for MGCP from thymus-independent to thymus-dependent and that it was effective by intranasal route.

[Evaluation of ventricular synchronization by fourier phase analysis in a radionuclide ventriculography]

INTRODUCTION

Radionuclide ventriculography (RNV) evaluates segmental and global ventricular contractility and also detects conduction abnormalities.

OBJECTIVE

To assess the temporal parameters of ventricular synchronization in the normal heart by a third harmonic (3H) Fourier phase analysis in a RNV and introduce this technique in our center.

MATERIAL AND METHODS

Thirty normal subjects (19 men and 11 women) were included. An equilibrium RNV was performed in 35 degree left anterior oblique projection with 10 degree caudal tilt. The onset (T0); mean time (T(m)); total contraction time (T(t)); final time (T(f)) and propagation time (T(p)) for right (RV) and left ventricle (LV); as well as total propagation time (T(TP)); interventricular time (T(RV-LV)) and septum-lateral wall conduction time (T(S-LW)) were measured on the 3H Fourier histogram of the time-activity curve.

RESULTS

Right ventricle contraction started 5 ms before that of the left ventricle (T(0RV) = 66 +/- 38 ms; T(OLV) = 71 +/- 30 ms), with a longer total contraction time (T(tVD) = 67 +/- 28 ms vs T(tVI) = 64 +/- 38 ms). Total propagation time (T(TP)) was 69 +/- 37 ms and the interventricular time (T(RV-LV)) was 2 +/- 25 ms. Contraction progressed from septum to lateral wall, with a septum-lateral wall conduction time (T(S-LW)) of 4 +/- 22 ms.

CONCLUSION

Simultaneous contraction of right and left ventricles can be quantified by RNV phase analysis, providing a useful tool for ventricular resynchronization assessment in multisite pacing.

Genetic Diversity of Panicum mosaic virus Satellite RNAs in St. Augustinegrass

ABSTRACT St. Augustine decline is a viral disease caused by Panicum mosaic virus (PMV) alone or in combination with a satellite virus (SPMV) and/or satellite RNAs (satRNAs). A ribonuclease protection assay (RPA) was used to evaluate the genetic diversity of PMV satRNAs isolated from 100 naturally infected St. Augustinegrass plants (Stenotaphrum secundatum). Distinctive satRNA RPA profiles were observed for 40 of 52 samples from College Station (CS) and 37 of 48 samples from Corpus Christi (CC), Texas. A dendrogram constructed from the RPA data revealed that satRNAs were grouped in two distinct clusters based on their place of origin. From 100 samples, only 4 satRNAs from CS were placed in the CC group, and only 2 satRNAs from CC were placed in the CS group. The data show that there is genetic variability in PMV satRNAs in naturally occurring infections, and distinct geographically separate populations can be identified from CC and CS.

Sonography of gallstones and biliary dilatation without a visible aetiology: the infrequency of obstructing choledocholithiasis

This paper describes 50 consecutive patients who sonographically had gallbladder stones and dilated bile ducts, but no visible aetiology for the dilatation. We reviewed these cases to determine the frequency of choledocholithiasis in this setting. Common duct stones caused obstruction in only 36% of these patients. Other aetiologies included strictures due to chronic pancreatitis or prior stone passage in 24% of the patients, and malignant obstruction in 16%. In 24% of the patients, no cause was found for biliary dilatation; common duct stones or obstructing tumours were excluded in the group. Since aetiologies other than stones are likely in a majority of cases, further preoperative workup (CT, percutaneous transhepatic cholangiography, ERCP) or intraoperative cholangiography (if the patient requires urgent cholecystectomy) is indicated. The additional studies should provide a diagnosis, help determine whether or not the common duct should be explored, or avoid unnecessary operation in case of incurable malignancy.