Evaluation of the influence of cytokine production on the immune response profile of calves in the first 30 days of life

Author(s)

Carolina de Lara Shecaira

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2017-09-21

Examining board members

Fernando José Benesi; Milton Ricardo Azedo; Camila Freitas Batista; Paulo Eduardo Brandão; Viviani Gomes

• Advisor: Fernando José Benesi

Abstract

The first 30 days post-birth of the calf, called the neonatal period, is characterized by large immunological development. The immune system begins to develop even at the beginning of gestation, but after birth, even if morphologically developed, it is not fully functional due to the absence of antigenic stimuli. In addition, the anatomical and physiological characteristics of bovine placentation are an impediment to the transfer of immunity during gestation, so the fetus develops without the influence of maternal immunoglobulins, being highly dependent at the beginning of the extrauterine life of the transference of passive immunity via colostrum. The characteristics of the immune system of the calf in its neonatal period make it very susceptible to diseases. Knowing the immune behavior of newborn calves can help reduce the incidence of diseases and the cost of this animal, and increase their well-being. The aim of this study was to evaluate the immune response pattern of the neonate in the first 30 days of life through evaluations of phagocytic activity and oxidative metabolism of circulating neutrophils and T lymphocyte (CD3 +) immuno-typing and its subpopulations (CD4 + and CD8 +) by flow cytometry and the gene expression of the IL-4, IL-10, IL-12 and IFN-ϒ cytokines by Real-Time PCR. Physical examination, blood count and passive immunity assessment were considered as inclusion criteria to guarantee the health of the animals during the experimental period. Based on the results obtained in this research it can be concluded that: granulocyte phagocytosis activity was constant in the 30 days evaluated; the production of reactive oxygen species by granulocytes was observed in the basal and stimulated assays; and with similar behavior, presenting the two trials, highest percentages on days 1, 25 and 30 p.n .; the CD3 + lymphocytes and their subpopulations: CD4 +, CD8 +, these presented percentages similar to those found in adult bovines; and the CD4 + / CD8 + ratio increased at 30 days of life, due to the increase in CD4 +. It was not possible to measure the gene expression of IL-4 and IFN-ϒ cytokines in any of the evaluated moments; However, IL-10 and IL-12 cytokine gene expression was observed, with an inclination to the Th2 profile induced by the more frequent expression of IL-10, with the influence of the gene expression of the cytokines IL-10 and IL- 12 on leukogram, granulocyte activity, and T lymphocyte subpopulations. (AU)

• FAPESP's process: 14/02418-5 - Evaluation of the influence on cytokine production profile of immune response in calves in the first 30 days of life
• Grantee: Carolina de Lara Shecaira
• Support Opportunities: Scholarships in Brazil - Doctorate