Rabbit Antisera to Enterobacteriaceae Isolated from HLA-B27 Positive Patients with Ankylosing Spondylitis (AS) are Lytic for the Mononuclear Cells of as Patients

: Vaccines prepared from Gram-negative bacteria isolated from the stools of HLA-B27 positive AS patients were used to immunize rabbits. Three of the sera obtained were lytic in vitro for the mononuclear cells of HLA-B27 positive AS patients. One of these sera discriminated between AS patients and healthy HLA-B27 positive individuals. Cytolysis was determined in an automated, non-radioactive assay based on the release of carboxyfluorescein diacetate and the incorporation of propidium iodide.