Pablo Oyarzun Andrade^1,2 | Claudio Henríquez³ | Juan G. Navedo⁴ | Josefina Gutiérrez^1,2 | Consuelo Martorell¹ | John Quiroga³ | Jonathan Vergara^1,2 | Claudio Verdugo¹

1. Ecology and Evolution of Infectious Diseases Lab, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile; 2. Programa de Doctorado en Ciencias mención Ecología y Evolución, Escuela de Graduados, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile; 3. Instituto Farmacología y Morfofisiología, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile; 4.- Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.

Ponente: Pablo Oyarzun Andrade, p.oyarzun.andrade@gmail.com

The maintenance and activation of the immune system as a response against a pathogen generates different benefits reflected mainly in survival and fitness of the host, however, it also produces changes at the physiological level, forcing a reallocation of resources from other systems or activities, generating trade-offs and thus affecting host life history traits, such as migration. Therefore, the expenses caused using the immune machinery generate infection costs, which can affect behavioural, metabolic and other characteristics. One of the most active immunological phases and, therefore, one of those with the highest energy demand is the APR (acute phase response), which occurs in the first 24 hours after an infection or pathogenic challenge, triggering a cascade of biochemical signals, driven mainly by the release of cytokines. To evaluate these costs, we used Limosa haemastica as a model. The changes in the immune system were measured through BKA with Staphylococcus aureus, haptoglobin assay and total immunoglobulin: IgY, of 16 free-living captive individuals (8 controls and 8 treated) induced by an experimental immune challenge with a new antigen (Influenza A virus of swine) in 144 samples, both in acute and chronic phase responses. Preliminary results in the BKA assay do not show differences between the control group and the immunized group, but it is relevant to observe that for both groups and at all the time points evaluated, the reduction percentage of bacterial replication was between 40% and 45%. This is striking, because the challenge was against a specific antigen, so BKA would be showing a pattern of maintenance of the innate immune system and by the activation of the complement system through the classical pathway, which responds to the formation of an antigen-antibody complex. Fondecyt N° 1191769. ANID scholarships N° 21212004, 21201700, 21180753.