ANTIBODIES AGAINST PROTEINS OF STREPTOCOCCAL HYALURONATE SYNTHASE BIND TO HUMAN FIBROBLASTS AND ARE PRESENT IN PATIENTS WITH RHEUMATIC-FEVER

Antibodies directed against the streptococcal 42 kDa hyaluronate synth ase and a 56 kDa auxiliary protein bound to the surface of intact huma n fibroblasts in vitro. Staining was most prominent during the detachm ent phase of mitosis. In eukaryotic plasma membranes a 52 kDa protein was recognized by the antiserum against the 56 kDa streptococcal prote in. Since the cross-reacting proteins could be involved in immunologic al mimicry between streptococcal and human antigens leading to heart c ell necrosis, the reactivity of sera from patients with rheumatic feve r was compared with that of sera from healthy or streptococcal infecte d persons. The sera from patients with rheumatic fever showed a higher reactivity against the 56 kDa protein than those from healthy persons or from patients with an antibiotic treated streptococcal infection. This difference was not observed for the 42 kDa protein. These sera we re able to lead to cell lysis in the presence of complement.