Intranasal immunization of lambs with serine/threonine phosphatase 2A against gastrointestinal nematodes Mohamed Fawzi, Elshaima Cruz-Bustos, Teresa Gomez Samblas, Mercedes Gonzalez Gonzalez, Gloria Solano, Jennifer Gonzalez Sanchez, Maria Elena Pablos Torró, Luis Miguel de Corral Caridad, María Jesús Cuquerella, Montserrat Osuna, Antonio Alunda, José María vaccine gastrointestinal nematodes recommbinat protein Seven 3-month-old, female, helminth-free lambs were immunized intranasally with three doses (1 mg total) of a recombinant part of the catalytic region of the serine/threonine phosphatase 2A (PP2Ar) (group 1 [G1]). In addition, four lambs were used as an adjuvant control group (G2), four as unimmunized, infected controls (G3), and four as unimmunized, uninfected controls (G4). Fifteen days after the last immunization, lambs from G1, G2, and G3 were challenged with 10,000 larval stage 3 (L3) organisms in a plurispecific nematode infection composed of ca. 40% Trichostrongylus colubriformis, 40% Haemonchus contortus, and 20% Teladorsagia circumcincta. All the lambs were clinically monitored throughout the experiment. Parasitological (fecal egg output and immunological response), biopathological (packed-cell volume and leukocyte and eosinophil counts), and zootechnical (live-weight gain) analyses were conducted. On day 105 of the experiment, all the animals were slaughtered and the adult worm population in their abomasa examined. Intranasal administration of PP2Ar with bacterial walls as an adjuvant elicited a strong immune response in the immunized lambs, as evidenced by their humoral immune response. Immunized animals and animals receiving the adjuvant shed significantly (P < 0.001) fewer numbers of parasites' eggs in their feces. The immunization significantly reduced the helminth burden in the abomasa by the end of the experiment (>68%), protection being provided against both Haemonchus and Teladorsagia. Live-weight gain in the immunized lambs was similar to that in the uninfected controls versus the infected or adjuvanted animal groups. Our results suggest that heterologous immunization of ruminants by intranasal administration may be efficacious in the struggle to control gastrointestinal helminths in these livestock. 2025-01-20T09:14:03Z 2025-01-20T09:14:03Z 2013-09 journal article Mohamed Fawzi E, Cruz Bustos T, Gómez Samblas M, González-González G, Solano J, González-Sánchez ME, De Pablos LM, Corral-Caridad MJ, Cuquerella M, Osuna A, Alunda JM. 2013. Intranasal Immunization of Lambs with Serine/Threonine Phosphatase 2A against Gastrointestinal Nematodes. Clin Vaccine Immunol 20:. https://hdl.handle.net/10481/99657 10.1128/CVI.00336-13 eng Spanish Ministry of Science and Technology grant (AGL2011-26098) “Programa de Ayudas para la Transferencia de Resultados de Investigación” of the OTRI, University of Granada, Spain. http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Clinical and Vaccine Immunology