Name: Hugo Orlando Hernandez
Affiliation: Large Animal Medicine & Surgery Service, Teaching Hospital. Faculty of Veterinary Science, National University of La Plata. La Plata, Argentina.
Position: Assistant Professor
Term: April 2018 to January 2019
Host researcher: Dr. Makoto Igarashi (English / Japanese)
Circumstances of application:
I had the chance to be a JICA participant during ten months between 2011 and 2012. During that time I learned many different techniques and skills, and also I experienced the work and research environment that characterize the NRCPD. After that I was able to apply the knowledge obtained here in many aspects of my professional life, but above all it was useful for start to work and collaborate in equine protozoal myeloencephalitis (EPM) diagnosis in argentinian horses. In this sense I have collaborated with the immunoparasitology laboratory of my faculty during the last years and that is why I decided to apply for the foreign researcher position offered by the center.
Research activity in NRCPD:
The general objective of the proposed research plan was to produce new recombinant proteins from Sarcocystis neurona, the causative agent of EPM. In this sense, parasite was collected from opossum gut in different fields around La Plata city, where positives horses was detected. All recently developed serological tests focus on the use of parasite surface antigens (SnSAGs). Even, the most recent of them, use chimeric recombinant proteins in an attempt to improve tests sensitivity and specificity. This is why our work focused on the production of recombinant proteins 2, 3 and 4; besides we were also trying to produce various combinations of them as a chimeric protein. Finally we could produce and express rSAG 2, rSAG 2/3 and rSAG 2/3/4 and, after purification, we used it for ELISA test and Immunoblot technique. On the other hand, part of the work consisted on analyze positive and negative sera samples from horses coming from various sites around La Plata city. With the intention of establishing inconsistencies in the results obtained, and establishing the presence of false positives or false negatives. For this, samples obtained from clinical cases of the condition that were positive with the methods used in the immunoparasitology laboratory (Arg.) were re-analyzed, as well as samples obtained from healthy and negative animals with those same techniques.
Finally, in the last few month and after parasites samples arrives to the NRCPD from Argentina, we start in vitro culture of sarcocysts and sporocysts obtained from the small intestine of the opossum.
For future plans, I believe that much remains to be done regarding the production of recombinant proteins and it would be very useful to produce and test other chimeric proteins (for example 4/3). The latter in order to establish the different immunogenicity of the surface proteins of the parasite. Even the production of ELISA tests with different antigenic combinations can allow us to improve the sensitivity and specificity values of them. In addition, if we have success with in vitro cultures, it would be very interesting to perform infections in mice to evaluate the infectivity of the parasites in this model. And also this could allow us to produce antibodies wich can be used in a immunostaining technique, for example.
I expect to be able to present a proposal for a joint work between my Faculty and the NRCPD to continue working closely together in the future.