Studies of streptococcal membrane antigen-binding cells in acute rheumatic fever

Blood specimens from patients with rheumatic heart disease in both India and New Mexico were typed for the presence of B cell alloantigen 883 by use of a mouse monoclonal antibody with identical specificity to the original 883 human alloantiserum. Strong relative segregation was recorded for 883 positive B cell typing in patients with rheumatic heart disease in both geographic locations as compared with that in normal unaffected controls. In patients with acute rheumatic fever, studies of actual B-lymphocyte membrane binding by anti-883 monoclonal antibody and sonicated group A streptococcal membrane antigens showed separate but contiguous localization on isolated cell surfaces. Although physically distinct, 883 B cell alloantigen and sonicated group A streptococcal membrane antigens moved together in cell capping studies after incubation at 37°C. These findings reaffirm the apparent close association between 883 B cell alloantigen and rheumatic heart disease. They also demonstrate that the B cell alloantigen 883 itself is physically distinct from but very close to sites on antigen-reactive B cells actually binding to group A streptococcal membrane antigens.