Laura E. Orozco Vega

Publications (2)3.77 Total impact

• Article: Anaplasma marginale: análisis de las secuencias del fragmento variable del gen msp1α y del gen msp4 de cuatro nuevas cepas mexicanas

  José de la Fuente, Laura E. Orozco Vega, Rafael Jiménez Ocampo, Rodrigo Rosario-Cruz, Sergio D. Rodríguez Camarillo
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  ABSTRACT: La anaplasmosis bovina ocasiona pérdidas cuantiosas a la ganadería en países en desarrollo, y el diseńo de vacunas se ve obstaculizado por la amplia diversidad genética y antigénica que este organismo presenta en cepas de diferentes regiones geográficas. El objetivo del trabajo fue comparar las secuencias de cuatro cepas mexicanas de A. marginale no tipificadas respecto a los genes msp1α y msp4. Se usaron las secuencias de MSP-1a y MSP4, dos de las proteínas del complejo principal de superficie, y que se han usado para estudios filogenéticos. Usando iniciadores específicos, para la región variable del gen msp1 α y el gen msp4, se amplificó el ADN de las cepas Pte. de Ixtla, Mor., Aguascalientes, Ags., Pichucalco y Sta. Martha, Chis. El análisis de las secuencias nucleotídicas y de aminoácidos para msp1α reveló una clara similitud entre los aislado Pichucalco y Sta. Martha ambas de Chiapas, al igual que contra los aislados México, Morelos y Veracruz. Los aislados Aguascalientes y Pte. de Ixtla demostraron ser diferentes entre ellos, de las otras cepas mexicanas, y de otros países, mientras que para msp4 no se observó variación en ninguna de las cepas mexicanas hasta el momento reportadas, las cuales contienen 849 pb y coinciden altamente con diversos aislados del mundo. El estudio regional o nacional del grado de conservación de estas proteínas abriría posibilidades para el diseńo de una vacuna con base en este tipo de antígenos y se podría predecir su eficacia.
  Técnica Pecuaria en México. 01/2008;
• Article: Anaplasma marginale field challenge: protection by an inactivated immunogen that shares partial sequence of msp1alpha variable region with the challenge strain.

  Laura E Orozco Vega, Sergio D Rodríguez, Germinal J Cantó Alarcón, Rafael López Flores, Rafael Jiménez Ocampo, Miguel Angel García Ortiz, Jesús Francisco Preciado de la Torre, Edmundo E Rojas Ramírez
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  ABSTRACT: Twenty four Hereford heifers free of anaplasmosis were allotted into three groups of eight animals each and inoculated three times with adjuvant in Puck saline as control or 50 microg and 100 microg of total protein of Anaplasma marginale initial bodies from three Mexican strains which share the same variable region of msp1alpha and msp4. Inoculation with the adjuvant or the immunogen at either of the two protein doses did not induce any undesirable changes attributable to inoculation in vaccinates or controls. On day 78 post vaccination animals were released in a ranch where bovine Anaplasmosis is endemic. The A. marginale strain prevalent in this ranch shares some of the msp1alpha tandem repeats with and the strains used in the vaccine. After release, all animals became infested with Boophilus microplus ticks and flies. During the challenge period, between days 279 and 300, loss of PCV due to clinical anaplasmosis in control animals was statistically higher from vaccinated animals. Likewise, controls mean peak rickettsemia was also significantly higher (p< or =0.01) than vaccinates' rickettsemias. The antibody responses of all vaccinates after the third vaccination reached OD values above 2.0 on day 49 and were different from controls (p<0.01). IgG(2) responses from both groups of vaccinates were different from controls (p<0.01). Vaccinates which required treatment, also showed the lowest IgG(2) and substantial IgG(1) responses. After contact with the rickettsia, controls developed clinical disease and 7 out of 8 required treatment, while vaccinates in general showed no substantial changes in hematocrit or rickettsemia and only one animal in each group required treatment. Our present results show that vaccination with either 50 microg or 100 microg of protein from purified IB derived from three strains induced protection to resist the challenge with the a field strain that shares some of the tandem repeats of MSP1a.
  Vaccine 02/2007; 25(3):519-25. · 3.77 Impact Factor