Scientists from the National Institute of Allergy and Infectious Disease/National Institutes of Health at the Rocky Mountain Laboratory (Hamilton, MO) have generated the first effective vaccine against chlamydial genital infections. By introducing ex vivo sensitized dendritic cells (DCs) into naive mice, they successfully induced T-cell immunity in vivo against the elusive pathogen, Chlamydia trachomatis. In a recent issue of The Journal of Experimental Medicine (188:809– 819, 1998>), Harlan Caldwell and colleagues show that chlamydia-pulsed DCs phagocytose heat-killed bacteria, correctly present chlamydial antigens, and induce CD4+ T-cell cytokine responses similar to those of chlamydia-infected mice. More importantly, the approach resulted in protective immunity against chlamydial genital tract infection in mice equal to immunity obtained after infection with live bacteria. "This study shows it's feasible to generate an efficacious vaccine against chlamydial genital tract infection," claims Caldwell. "It could be very useful for developing vaccines against other infectious diseases that warrant aggressive, unconventional therapies."