[Evaluation of phagocytosis, bactericidal effect, and cytotoxicity of Pasteurella haemolytica and Pasteurella multocida in bovine alveolar macrophages].
Evaluation of phagocytosis and bactericidal effect of Pasteurella haemolytica and P. multocida was conducted on bovine alveolar macrophages freshly obtained through bronchioalveolar washings from live animals. Cytotoxic activity of these bacteria on the alveolar macrophages was evaluated through the simple visual assay in microplates, using bovine blood leukocytes as a comparative target cell. In order to evaluate phagocytosis the following variables were considered P. haemolytica and P. multocida (independently) in contact with alveolar macrophages, P. haemolytica and P. multocida in suspension as a positive control of bacterial growth, and RPMI-1640 medium alone, as a negative control of bacterial growth. To measure bactericidal capacity, bacteria were incubated with plastic adhered alveolar macrophages at 30 minutes and 3 hours intervals. Samples incubated 30 minutes were taken as phagocytosis-base readings and at the 3 h interval to evaluate bactericidal capacity of the alveolar macrophages on phagocytized bacteria. Reading of the samples of each evaluation was conducted in a spectrophotometer a 380 nm. Phagocytosis results indicated that bacterial proliferation was higher when bacteria were alone as compared when they were with alveolar macrophages (p < 0.05). Bactericidal capacity of the macrophages was efficient because bacterial numbers were higher in the first evaluation as compared to the second (p < 0.05). It was demonstrated that the cytotoxic effect of P. haemolytica was more severe on blood leukocytes as compared to alveolar macrophages (p < 0.05). There was no evidence of P. multocida cytotoxicity on the evaluated cells. With the development of this technique for the obtention of alveolar macrophages and using spectrophotometry for the phagocytosis and bactericidal effect evaluations, numerous variables and samples can be tested, such as opsonized bacteria or to measure the behaviour of alveolar macrophages infected with different agents involved in the bovine pneumonic complex.
Morales
J F
JF
Proyecto Complejo Neumónico de Rumiantes, CENID-Microbiología, INIFAP-SARH, México, D.F., México.
Ayala
D
D
Jaramillo
L
L
Trigo
F J
FJ
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002417:Cattle / Q000382:microbiology*; D002478:Cells, Cultured; D016676:Macrophages, Alveolar / Q000382:microbiology / Q000502:physiology*; D016978:Mannheimia haemolytica / Q000472:pathogenicity / Q000502:physiology*; D016979:Pasteurella multocida / Q000472:pathogenicity / Q000502:physiology*; D010587:Phagocytosis; D014774:Virulence
Evaluación de fagocitosis, efecto bactericida y citotoxicidad de Pasteurella haemolytica y Pasteurella multocida en macrofagos alveolares de bovinos.