The effect of Pasteurella haemolytica A1 leukotoxic culture supernate on the in vitro proliferative response of bovine lymphocytes

• Published in: Veterinary immunology and immunopathology Vol. 29; no. 1-2; p. 41
• Main Authors: Majury, A L, Shewen, P E
• Format: Journal Article
• Language: English
• Published: Netherlands 1991
• Subjects: Animals; Antibodies, Monoclonal - immunology; B-Lymphocytes - immunology; Bacterial Toxins - genetics; Bacterial Toxins - immunology; Bacterial Toxins - isolation & purification; Cattle; Culture Media; Cytotoxicity, Immunologic - immunology; Dogs; Humans; Lymphocyte Activation - immunology; Mannheimia haemolytica - immunology; Rabbits; Recombinant Proteins - immunology; Swine; T-Lymphocytes - immunology
• ISSN: 0165-2427
• DOI: 10.1016/0165-2427(91)90051-D

The effect of sublethal concentrations of the Pasteurella haemolytica leukotoxic culture supernate on bovine lymphocyte blastogenesis was investigated. Blastogenesis in cultures stimulated with either concanavalin A (Con A) or pokeweed mitogen (PWM) was inhibited in the presence of the supernate, as was the response to purified protein derivative in lymphocytes from BCG-vaccinated cattle. Partially purified leukotoxin had a similar effect. Pre-incubation of the leukotoxic supernate with a polyclonal rabbit antiserum raised to the immunogenic molecule of recombinant leukotoxin (r LktA) abrogated this effect, implicating leukotoxin as the factor responsible for the inhibition. B cell enriched cultures tended to be more sensitive to leukotoxic effects than did T cell enriched cultures. Although only ruminant cells are susceptible to the lethal effects of P. haemolytica leukotoxin, the toxin did inhibit both Con A- and PWM-induced proliferation of human and dog lymphocytes. As well, at high leukotoxin doses, Con A-stimulated pig lymphocyte proliferation was reduced. Rabbit lymphocytes were not affected by leukotoxin in either Con A- or PWM-stimulated cultures.