Genome-Based Vaccinology Applied to Bovine Babesiosis

Genomics approaches in veterinary research have been a very useful tool to identify candidates with potential to be used in prevention of animal diseases. In Babesia, genome information analysis has elucidated a wide variety of protein families and some members are described in this chapter. Here, we present some of the most recent studies about B. bovis and B. bigemina genomes where some proteins have been identified with potential to prevent infections by these parasites

Evaluation of the humoral and mucosal immune response of a multiepitope vaccine against COVID-19 in pigs

IntroductionThis study evaluated the immune response to a multiepitope recombinant chimeric protein (CHIVAX) containing B- and T-cell epitopes of the SARS-CoV-2 spike’s receptor binding domain (RBD) in a translational porcine model for pre-clinical studies.MethodsWe generated a multiepitope recombinant protein engineered to include six coding conserved epitopes from the RBD domain of the SARS-CoV-2 S protein. Pigs were divided into groups and immunized with different doses of the protein, with serum samples collected over time to determine antibody responses by indirect ELISA and antibody titration. Peptide recognition was also analyzed by Western blotting. A surrogate neutralization assay with recombinant ACE2 and RBDs was performed. Intranasal doses of the immunogen were also prepared and tested on Vietnamese minipigs.ResultsWhen the immunogen was administered subcutaneously, it induced specific IgG antibodies in pigs, and higher doses correlated with higher antibody levels. Antibodies from immunized pigs recognized individual peptides in the multiepitope vaccine and inhibited RBD-ACE2 binding for five variants of concern (VOC). Comparative antigen delivery methods showed that both, subcutaneous and combined subcutaneous/intranasal approaches, induced specific IgG and IgA antibodies, with the subcutaneous approach having superior neutralizing activity. CHIVAX elicited systemic immunity, evidenced by specific IgG antibodies in the serum, and local mucosal immunity, indicated by IgA antibodies in saliva, nasal, and bronchoalveolar lavage secretions. Importantly, these antibodies demonstrated neutralizing activity against SARS-CoV-2 in vitro.DiscussionThe elicited antibodies recognized individual epitopes on the chimeric protein and demonstrated the capacity to block RBD-ACE2 binding of the ancestral SARS-CoV-2 strain and four VOCs. The findings provide proof of concept for using multiepitope recombinant antigens and a combined immunization protocol to induce a neutralizing immune response against SARS-CoV-2 in the pig translational model for preclinical studies

“TRIMETOPRIM CON SULFAMETOXAZOL PARA LA ERRADICACIÓN DE BLASTOCYSTIS SP. EN ESCOLARES”

La prevalencia mundial de Blastocystis sp. oscila entre 2% y 50% y está estrechamente ligada a malas condiciones de saneamiento básico, hacinamiento y desnutrición. En países desarrollados, se reportan frecuencias bajas mientras que en países en vías de desarrollo, Blastocystis sp. es uno de los parásitos intestinales mayormente reportados, siendo la población infantil la más afectada. En cuanto al tratamiento, varios medicamentos se han probado: el metronidazol con resultados variables y sin respuesta al tratamiento, el secnidazol que ocasionalmente erradica a Blastocystis y el uso de la nitazoxanida como antiparasitario se ha cuestionado como antiparasitario. Asimismo, se ha puesto a prueba el fármaco trimetoprim con sulfametoxazol para la erradicación de Blastocystis con alto grado de efectividad. En nuestro medio, se tiene poca experiencia acerca del éxito terapéutico del medicamento, por lo que en el presente trabajo se pretende probar la efectividad como antiparasitario en parasitosis única y asociada a parasitos comensales. Se colectaron 120 muestras, en serie de 3, de alumnos de la Escuela Primaria Rural Federal “Profesor Rafael Ramírez” y de niños del servicio de consulta externa del Hospital Infantil “Eva Sámano de López Mateos”, las cuales se procesaron por examen directo en fresco, técnicas de concentración por flotación y por sedimentación y tinción de Kinyoun. De 120 niños analizados, el 68% cursaba con alguna parasitosis, siendo Blastocystis sp. el más frecuente, asociado en un 54% a otros parásitos y como único agente en un 30%. En cuanto a la efectividad del medicamento, fue aplicada la prueba de Fisher demostrando que existe diferencia estadísticamente significativa en el tratamiento en parasitosis única y mixta

Hap2, a novel gene in Babesia bigemina is expressed in tick stages, and specific antibodies block zygote formation

Abstract Background Bovine babesiosis is a tick-borne disease caused by the protozoan parasites of the genus Babesia. In their host vector, Babesia spp. undergo sexual reproduction. Therefore, the development of sexual stages and the subsequent formation of the zygote are essential for the parasite to invade the intestinal cells of the vector tick and continue its life-cycle. HAP2/GCS1 is a protein identified in plants, protozoan parasites and other organisms that has an important role during membrane fusion in fertilization processes. The identification and characterization of HAP-2 protein in Babesia would be very significant to understand the biology of the parasite and to develop a transmission-blocking vaccine in the future. Results To isolate and sequence the hap2 gene DNA from an infected bovine with Babesia bigemina was purified. The hap2 gene was amplified, cloned and sequenced. The sequences of hap2 from four geographically different strains showed high conservation at the amino acid level, including the typical structure with a signal peptide and the HAP2/GSC domain. Antisera anti-HAP2 against the conserved extracellular region of the HAP2 amino acid sequence were obtained from rabbits. The expression of hap2 in the host and vector tissues was analyzed by using semi-quantitative RT-PCR, and the protein was examined by western blot and immunofluorescence. Based on the RT-PCR and WB results, HAP2 is expressed in both, sexual stages induced in vitro, and in infected ticks as well. We did not detect any expression in asexual erythrocytic stages of B. bigemina, relevantly anti-HAP2 specific antibodies were able to block zygotes formation in vitro. Conclusion Babesia bigemina HAP2 is expressed only in tick-infecting stages, and specific antibodies block zygote formation. Further studies regarding the function of HAP2 during tick infection may provide new insights into the molecular mechanisms of sexual reproduction of the parasite