title: Chemotactic response of equine polymorphonuclear leucocytes to Streptococcus equi.
abstract: Streptococcus equi infection in horses is characterised by intense infiltration of lymph nodes by polymorphonuclear leucocytes (PMNs) suggesting a potent chemotactic response to the organism or its products. Equine PMNs were separated using Ficoll-Hypaque medium and used in an assay of chemotaxis under agarose to study the components of S equi involved in this response. Results showed that complement-derived chemotactic factors generated by activation of the alternative complement pathway were important in chemotactic responses to S equi. Both whole bacteria and peptidoglycan preparations were potent complement activators, whereas purified M protein was less active. In contrast, S equi culture supernatant protein did not activate complement; instead it directly inhibited migration of PMNs. Moreover, PMNs, when incubated with culture supernatant of a non-haemolytic strain, showed signs of cellular degeneration suggesting the presence of a cytotoxin distinct from haemolysin.
authors.affiliation: Department of Veterinary Microbiology, Immunology and Parasitology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
authors.forename: M M
authors.initials: MM
authors.lastname: Muhktar
authors.forename: J F
authors.initials: JF
authors.lastname: Timoney
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000502:physiology*; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000502:physiology*; D002352:Carrier Proteins; D002634:Chemotaxis, Leukocyte; D006736:Horses / Q000097:blood*; D066298:In Vitro Techniques; D009504:Neutrophils / Q000502:physiology; D010457:Peptidoglycan / Q000502:physiology*; D013291:Streptococcus / Q000502:physiology*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D010457:Peptidoglycan; C014689:streptococcal M protein