Desarrollo de una vacuna conta Plasmodium vivax

De las cinco especies parasitarias causantes de malaria en el humano, Plasmodium vivax produce alrededor de 75 millones de casos anualmente, siendo la especie más prevalente en Asia y América.Con el incremento de la resistencia a los fármacos antimaláricos por parte del parásito y a los insecticidas por parte del vector transmisor (mosquitos del género Anopheles), la búsqueda de una vacuna eficaz contra los parásitos del género Plasmodium es cada vez más prioritaria.En los últimos años, enormes avances en la identificación de candidatos vacunales contra P. falciparum han sido alcanzados debido al rápido desarrollo tecnológico que ha permitido obtener la secuencia completa del genoma de este parásito, su perfil de transcripción génica (transcriptoma) y su proteoma.El alcanzar un nivel de conocimiento similar con respecto a P. vivax ha sido muy difícil, principalmente por la dificultad de mantener esta especie parasitaria en cultivo continuo in vitro.Esta limitación técnica se refleja en la información disponible de este parásito, teniendo actualmente solo datos parciales del genoma, transcriptoma y proteoma.Una de las principales diferencias de nuestro enfoque experimental, en lo que a desarrollo de vacunas se refiere, es que en vez de considerar buenos candidatos aquellos fragmentos proteicos fuertemente reconocidos por el sistema inmune, buscamos las porciones funcionalmente importantes, principalmente en la unión a las células diana. Mediante la bioinformática, biología molecular e inmunoquímica, nuestro grupo ha identificado y caracterizado 16 nuevos candidatos a vacuna frente a P. vivax. Recientemente, se concluyó el proteoma del estadio sanguíneo de la cepa VCG-1 de P.vivax, donde identificamos 734 proteínas, 31 de las cuales muestran características propias de buenos candidatos a vacuna caracterizados previamente.Desafortunadamente, uno de los mecanismos más eficientes utilizados por el parásito para evadir la respuesta inmune del hospedero es su alta variabilidad genética. Resultados de los estudios orientados a seleccionar las porciones conservadas de los candidatos a vacuna contra P. vivax realizados por nuestro grupo, serán presentados también.Estudios de inmunogenicidad y protección en monos Aotus (modelo experimental ideal para estudiar vacunas antimaláricas), utilizando regiones de alta capacidad de unión a las células diana y, a la vez, con baja variabilidad genética, nos han permitido obtener candidatos a vacuna frente a P. vivax muy promisorios como aquellos derivados de la proteína PvMSP-1. Estos fragmentos, expresados como proteínas recombinantes, confieren protección parcial al 50% de los animales inmunizados con dos dosis de ellos y al 80% de los animales inmunizados con tres dosis.Estos hallazgos, junto con las reglas obtenidas en los más de 30 años de investigación en el desarrollo de una vacuna eficaz contra P. falciparum , nos acercan cada vez más a la obtención de una vacuna multi-antígeno, multi-estadio contra P. vivax

A Comprehensive Review of the Immunological Response against Foot-and-Mouth Disease Virus Infection and Its Evasion Mechanisms

Foot-and-mouth disease (FMD) is a highly contagious viral disease, which has been reported for over 100 years, and against which the struggle has lasted for the same amount of time. It affects individuals from the order Artiodactyla, such as cattle, swine, sheep, wild animals from this order, and a few non-cloven hoofed species, such as mice and elephants. FMD causes large-scale economic losses for agricultural production systems; morbidity is almost 100% in an affected population, accompanied by a high mortality rate in young animals due to myocarditis or an inability to suckle if a mother is ill. The aetiological agent is an Aphthovirus from the family Picornaviridae, having seven serotypes: A, O, C, SAT1, SAT2, SAT3, and Asia 1. Serotype variability means that an immune response is serospecific and vaccines are thus designed to protect against each serotype independently. A host’s adaptive immune response is key in defence against pathogens; however, this virus uses successful strategies (along with most microorganisms) enabling it to evade a host’s immune system to rapidly and efficiently establish itself within such host, and thus remain there. This review has been aimed at an in-depth analysis of the immune response in cattle and swine regarding FMD virus, the possible evasion mechanisms used by the virus and describing some immunological differences regarding these species. Such aspects can provide pertinent knowledge for developing new FMD control and prevention strategie

Loop-Mediated Isothermal Amplification as Point-of-Care Diagnosis for Neglected Parasitic Infections

The World Health Organisation (WHO) has placed twenty diseases into a group known as neglected tropical diseases (NTDs), twelve of them being parasitic diseases: Chagas disease, cysticercosis/ taeniasis, echinococcosis, food-borne trematodiasis, human African trypanosomiasis (sleeping sickness), leishmaniasis, lymphatic filariasis, onchocerciasis (river blindness), schistosomiasis, soil-transmitted helminthiasis (ascariasis, hookworm, trichuriasis), guinea-worm and scabies. Such diseases affect millions of people in developing countries where one of the main problems concerning the control of these diseases is diagnosis-based due to the most affected areas usually being far from laboratories having suitable infrastructure and/or being equipped with sophisticated equipment. Advances have been made during the last two decades regarding standardising and introducing techniques enabling diagnoses to be made in remote places, i.e., the loop-mediated isothermal amplification (LAMP) technique. This techniques advantages include being able to perform it using simple equipment, diagnosis made directly in the field, low cost of each test and the techniques high specificity. Using this technique could thus contribute toward neglected parasite infection (NPI) control and eradication programmes. This review describes the advances made to date regarding LAMP tests, as it has been found that even though several studies have been conducted concerning most NPI, information is scarce for other

Mechanisms Associated with Trypanosoma cruzi Host Target Cell Adhesion, Recognition and Internalization

Chagas disease is caused by the kinetoplastid parasite Trypanosoma cruzi, which is mainly transmitted by hematophagous insect bites. The parasite’s lifecycle has an obligate intracellular phase (amastigotes), while metacyclic and bloodstream-trypomastigotes are its infective forms. Mammalian host cell recognition of the parasite involves the interaction of numerous parasite and host cell plasma membrane molecules and domains (known as lipid rafts), thereby ensuring internalization by activating endocytosis mechanisms triggered by various signaling cascades in both host cells and the parasite. This increases cytoplasmatic Ca2+ and cAMP levels; cytoskeleton remodeling and endosome and lysosome intracellular system association are triggered, leading to parasitophorous vacuole formation. Its membrane becomes modified by containing the parasite’s infectious form within it. Once it has become internalized, the parasite seeks parasitophorous vacuole lysis for continuing its intracellular lifecycle, fragmenting such a vacuole’s membrane. This review covers the cellular and molecular mechanisms involved in T. cruzi adhesion to, recognition of and internalization in host target cells

The DNA load of six high-risk human papillomavirus types and its association with cervical lesions

Background: Analysing human papillomavirus (HPV) viral load is important in determining the risk of developing cervical cancer (CC); most knowledge to date regarding HPV viral load and cervical lesions has been related to HPV-16. This study evaluated the association between the viral load of the six most prevalent high-risk viral types in Colombia and cervical intraepithelial neoplasia (CIN) frequency. Methods: 114 women without CIN and 59 women having CIN confirmed by colposcopy, all of them positive by conventional PCR for HPV infection in the initial screening, were included in the study. Samples were tested for six high-risk HPV types to determine viral copy number by real-time PCR. Crude and adjusted odds ratios (ORa) were estimated for evaluating the association between each viral type's DNA load and the risk of cervical lesions occurring. Results: The highest viral loads were identified for HPV-33 in CIN patients and for HPV-31 in patients without lesions (9.33 HPV copies, 2.95 interquartile range (IQR); 9.41 HPV copies, 2.58 IQR). Lesions were more frequent in HPV-16 patients having a low viral load (3.53 ORa, 1.16-10.74 95%CI) compared to those having high HPV-16 load (2.62 ORa, 1.08-6.35 95%CI). High viral load in HPV-31 patients was associated with lower CIN frequency (0.34 ORa, 0.15-0.78 95%CI). Conclusions: An association between HPV DNA load and CIN frequency was seen to be type-specific and may have depended on the duration of infection. This analysis has provided information for understanding the effect of HPV DNA load on cervical lesion development.This project was supported by the Basque Development Cooperation Agency, the Spanish International Development Cooperation Agency (AECID) (Project 10-CAP1-0197) and the Colombian Science, Technology and Innovation Department (COLCIENCIAS) (contract # 0709-2013)

Persistence, clearance and reinfection regarding six high risk human papillomavirus types in Colombian women: a follow-up study

Background: The design of new healthcare schemes which involve using molecular HPV screening means that both persistence and clearance data regarding the most prevalent types of HR-HPV occurring in cities in Colombia must be ascertained. Methods: This study involved 219 HPV positive women in all of whom 6 types of HR-HPV had been molecularly identified and quantified; they were followed-up for 2 years. The Kaplan-Meier survival function was used for calculating the time taken for the clearance of each type of HPV. The role of a group of independent variables concerning the time taken until clearance was evaluated using a Cox proportional-hazards regression model or parametric (log-logistic) methods when necessary. Regarding viral load, the Wilcoxon rank-sum test was used for measuring the difference of medians for viral load for each type, according to the state of infection (cleared or persistent). The Kruskal-Wallis test was used for evaluating the change in the women's colposcopy findings at the start of follow-up and at the end of it (whether due to clearance or the end of the follow-up period). Results: It was found that HPV-18 and HPV-31 types had the lowest probability of becoming cleared (1.76 and 2.75 per 100 patients/month rate, respectively). Women from Colombian cities other than Bogota had a greater probability of being cleared if they had HPV-16 (HR 2.58: 1.51-4.4 95% CI) or HPV-58 (1.79 time ratio: 1.33-2.39 95% CI) infection. Regarding viral load, HPV-45-infected women having 1 x 10(6) to 9.99 x 10(9) viral copies had better clearance compared to those having greater viral loads (1.61 time ratio: 1.01-2.57 95% CI). Lower HPV-31 viral load values were associated with this type's persistence and changes in colposcopy findings for HPV-16 gave the worst prognosis in women having low absolute load values. Conclusions: HPV infection clearance in this study was related to factors such as infection type, viral load and the characteristics of the cities from which the women came. Low viral load values would indicate viral persistence and a worse prognosis regarding a change in colposcopy findings

Human papillomavirus detection in women with and without human immunodeficiency virus infection in Colombia

Background: HIV infection leads to a decreasing immune response, thereby facilitating the appearance of other infections, one of the most important ones being HPV. However, studies are needed for determining associations between immunodeficiency caused by HIV and/or the presence of HPV during the course of cervical lesions and their degree of malignancy. This study describes the cytological findings revealed by the Papanicolaou test, laboratory characteristics and HPV molecular profile in women with and without HIV infection. Methods: A total of 216 HIV-positive and 1,159 HIV-negative women were invited to participate in the study; PCR was used for the molecular detection of HPV in cervical samples. Statistical analysis (such as percentages, Chi-square test and Fisher's exact test when applicable) determined human papillomavirus (HPV) infection frequency (single and multiple) and the distribution of six types of high-risk-HPV in women with and without HIV infection. Likewise, a logistic regression model was run to evaluate the relationship between HIV-HPV infection and different risk factors. Results: An association was found between the frequency of HPV infection and infection involving 2 or more HPV types (also known as multiple HPV infection) in HIV-positive women (69.0% and 54.2%, respectively); such frequency was greater than that found in HIV-negative women (44.3% and 22.7%, respectively). Statistically significant differences were observed between both groups (p = 0.001) regarding HPV presence (both in infection and multiple HPV infection). HPV-16 was the most prevalent type in the population being studied (p = 0.001); other viral types had variable distribution in both groups (HIV-positive and HIV-negative). HPV detection was associated with <500 cell/mm(3) CD4-count (p = 0.004) and higher HIV-viral-load (p = 0.001). HPV-DNA detection, <200 cell/mm(3) CD4-count (p = 0.001), and higher HIV-viral-load (p = 0.001) were associated with abnormal cytological findings. Conclusions: The HIV-1 positive population in this study had high multiple HPV infection prevalence. The results for this population group also suggested a greater association between HPV-DNA presence and cytological findings. HPV detection, together with low CD4 count, could represent useful tools for identifying HIV-positive women at risk of developing cervical lesions.This project was supported by the Basque Cooperation Agency Development and by the Spanish Agency for International Development Cooperation (AECID) (Project 10-CAP1-0197)

Malaria proteomic research

Malaria is one of the main infectious diseases in the world, particularly in tropical and subtropical areas. Among the species that can cause this disease, in recent years P. vivax has been growing due to its own attributes, which make it highly difficult to eradicate. This study was focused on analyzing and identifying the proteome of P. vivax during the blood stage through a mass spectrometry analysis (LC-MS-MS). Results allowed us to identify 743 proteins, of which 522 never had been described before. Furthermore, the comparison of the expression of these proteins with P. vivax transcriptional profile allowed us to corroborate the adaptive change in the P. vivax VCG-1 strain transcriptome, previously described.La malaria sigue siendo una de las principales enfermedades transmisibles del planeta, especialmente en áreas tropicales y subtropicales. Dentro de las diversas especies causantes de esta enfermedad, en los últimos años ha ganado relevancia el estudio de P. vivax debido a sus características propias, que la hacen especialmente difícil de erradicar. En el presente estudio, nos proponemos analizar e identificar las proteínas de la fase hemática de P.vivax mediante cromatografía líquida asociada a espectrometría de masas en tándem (LC-MS-MS). Los resultados del estudio nos permitieron identificar 743 proteínas, de las que 522 no habían sido previamente descritas. Además, la comparación del perfil de expresión de estas proteínas con el perfil transcripcional de P. vivax nos permitió corroborar lo descrito en estudios anteriores: el cambio adaptativo en el perfil transcripcional de la cepa VCG-1 de P. vivax

Combinatorial formulas for Kazhdan-Lusztig polynomials with respect to W-graph ideals

In \cite{y1} Yin generalized the definition of $W$-graph ideal $E_J$ in weighted Coxeter groups and introduced the weighted Kazhdan-Lusztig polynomials $\left \{ P_{x,y} \mid x,y\in E_J\right \}$, where $J$ is a subset of simple generators $S$. In this paper, we study the combinatorial formulas for those polynomials, which extend the results of Deodhar \cite{v3} and Tagawa \cite{h1}.Comment: 16 page