The objective of this proposal has been to establish the role of cervicovaginal antibody in determining enterobacterial colonization of the introital mucosa of the vaginal vestible in women with recurrent urinary infections. Longitudinal studies of women subject to reinfections of the urinary tract will include antibody measurements of their serum, cervicovaginal fluid, and salivary fluid using a solid phase radioimmunoassay technique which measures both specific antibody and total antibody in each of these body fluids. The variation imposed by the menstrual cycle on cervicovaginal antibody in control volunteers will serve as a background for interpreting the changes in susceptible women.