Humoral immune response to polypeptides of Ureaplasma urealyticum in women with postpartum fever.

We investigated the antibody response in women with postpartum fever from whom Ureaplasma urealyticum had been isolated from the bloodstream. Acute- and convalescent-phase sera were tested for immunoglobulin G to the polypeptides of five serovars (1, 2, 3, 4, and 8), representing the two genomic clusters of U. urealyticum, by the immunoblotting (Western) method. Convalescent-phase sera from the five patients reacted more intensely and with more (up to 27) polypeptides from each of the five serovars, whereas acute-phase sera reacted weakly and with few polypeptides. Although antibody responses in these women with systemic infection could be detected by the use of any of the five different serovars as antigens, the patterns that were produced differed clearly between the two genetic clusters (serovars 1 and 3 versus serovars 2, 4, and 8). Apparently, a single serovar could be used to detect ureaplasmal antibodies in humans regardless of the serovar of the infecting strain.