Stimulation of respiratory immunity by oral administration of Lactococcus lactis

VILLENA JULIO; MEDINA MARCELA; VINTIÑI ELISA; ALVAREZ SUSANA

CANADIAN JOURNAL OF MICROBIOLOGY

NRC Research Press

Lugar: Saskatoon, Canada; Año: 2008 vol. 54 p. 630 - 638

0008-4166

This work demostrates that non-recombinant Lactococcus lactis NZ, administered by the oral route at the proper dose, is able to improve resistance against pneumococcal infection. L. lactis NZ oral administration was able to improve pathogen lung clearance, increased survival of infected mice and reduced lung injuries. This effect was related to an up-regulation of the respiratory innate and specific immune responses. Administration of L. lactis NZ improved production of bronchoalveolar lavage fluid (BAL) TNF-á, enhanced recruitment of neutrophils into the alveolar spaces and induced a higher activation of BAL phagocytes compared to the control group. L. lactis NZ administered orally stimulated the IgA cycle, increased IgA+ cells in intestine and bronchus and improved production of BAL IL-4 and IL-10 during infection. Moreover, mice treated with L. lactis NZ showed higher levels of BAL anti-pneumococcal IgA and IgG. Taking into consideration that orally administered L. lactis NZ stimulates both the innate and the specific immune responses in the respiratory tract and that bacterial and viral antigens have been efficiently produced in this strain, L. lactis NZ is an excellent candidate for the development of an effective pneumococcal oral vaccine.