An early clue to the function of the Pmps came from neutralization studies which showed that antibodies directed against Pmp2, Pmp10, Pmp21, and PmpD blocked subsequent infection by C. pneumoniae and C. trachomatis, respectively, pointing to a role for Pmp2, Pmp10, Pmp21, and PmpD in the initial phase of infection (Wehrl et al. The gene discussed is PMP2; the disease is infection.