Frank Abbruscato

Treponema pallidum subsp. pertenue Displays Pathogenic Properties Different from Those of T. pallidum subsp. pallidum

ABSTRACT The present study described the susceptibility of C4D guinea pigs to cutaneous infection with Treponema pallidum subsp.pertenue Haiti B strain. The general manifestations of the disease in adults and neonates differ, to a certain degree, from those induced by T. pallidum subsp. pallidum Nichols strain. Noticeable differences between the infections were reflected in the character of the skin lesions, their onset and persistence, and the kinetics of the humoral response. The incidence and dissemination of cutaneous yaws lesions in very young guinea pigs were remarkably different from the low frequency observed in a similar age group of syphilis infection, 100 versus 17%, respectively. Moreover, as opposed to T. pallidum subsp. pallidum, T. pallidum subsp. pertenue does not cross the placenta. Offspring born to yaws-infected mothers did not produce immunoglobulin M antibodies and their organs, examined by PCR and rabbit infectivity test (RIT), were all negative. Examination of a large number of tissues and organs in adult, neonate, and maternal yaws by PCR and RIT clearly demonstrated that, unlike syphilis, there was a low incidence and short persistence of the yaws pathogen in internal organs. These findings stress the dermotropic rather than the organotropic character of yaws and provide further evidence of distinctive biological and pathological differences between yaws and venereal syphilis.

Vertical Transmission of Treponema pallidum to Various Litters and Generations of Guinea Pigs

The transmission of congenital syphilis was studied in a 4-generation guinea pig family with 10 litters and 38 offspring. By use of one or all of the following tests (ELISA-IgM, polymerase chain reaction, and rabbit infectivity), transplacental infection was demonstrated through 5 litters and up to 4 generations. Twenty-eight (93%) of 30 animals were positive by >/=1 test, and 2 (7%) were negative by 1 or 3 tests. While transmission of the pathogen appeared to be unaffected by the maternal acquisition of immunity, signs of smoldering infection in the young was suggested by the decline in humoral responses in successive progeny and by unusual rabbit infectivity test results. With each pregnancy there was a remarkable booster in the maternal humoral response, which dropped significantly prior to term. These findings shed new light on the understanding and interpretation of serologic testing during pregnancy and the perinatal period.

Immunization of Guinea Pigs with Treponema pallidum Recombinant Antigens Reveals the Presence of Novel Epitopes

The DNA technology employed in the construction and purification of recombinant antigens has the potential of creating epitopes with specificities other than those of native antigens. Such a phenomenon has been observed when guinea pigs were immunized with Treponema pallidum recombinant antigens, TmpA and TmpB, expressed in Escherichia coli K12. Adsorption of the immune sera with E. coli K12 and T. pallidum revealed the presence of antibodies directed against epitopes not present or exposed in the native antigens of the organisms from which the DNA has been cloned.