Evaluation of efficacy, cell mediated and humoral immune response of two different mycoplasma vaccines in specific pathogenic free chickens

Abstract

To investigate cell mediated and humoral immune response following vaccination with live mycoplasma vaccines, 100 specific pathogenic free chickens were inoculated with two different live mycoplasma vaccines: Mycoplasma gallisepticum (ts-11) and Mycoplasma synoviae (H); another 50 chickens were kept as controls (non vaccinated chickens). To evaluate the cell mediated immune response, peripheral blood leucocytes were obtained from vaccinated and control chicken groups and the lymphocyte proliferative response and nitric oxide level were determined. The immunomodulatory cytokines expression profiles elicited by the vaccines were evaluated; the mRNA expression level of interleukin-6 and gamma interferon were determined in spleen of vaccinated specific pathogenic free chickens. In parallel, sera collected from vaccinated and control chickens were examined using an enzyme-linked immunosorbent assay antibody kit to assess the humoral immune response. A challenge test was applied at 4th week post vaccination to all vaccinated chickens and controls against virulent strains of Mycoplasma gallisepticum and Mycoplasma synoviae. The results confirm the presence of consistent lymphoproliferation with production of interferon and nitric oxide in vitro in the two vaccinated chicken groups compared to the negative control. Moreover, the tested vaccines induced high seroconversion level with satisfactory protection (%) at 4th week post vaccination. It was concluded that the two live mycoplasma vaccines can protect the vaccinated chickens against Mycoplasma gallisepticum and Mycoplasma synoviae infections suggesting a significant role for cell-mediated immunity.

Keywords

• cell-mediated immunity
• humoral immune response
• interleukin-6
• mycoplasma infections
• vaccines