[Studies on immune response in mouse model of experimental Chlamydia trachomatis intrauterine infections].
An experimental model of Chlamydia trachomatis (C. trachomatis) intrauterine infections was established in mice. Using this model, studies were conducted on the immune response at the site of infection by applying the ABC staining method and monoclonal antibodies directed against each of the various species of immunocompetent cells. At the same time, the serum levels of C. trachomatis-specific IgA and IgG antibodies were also measured. The immunological correspondence of these serum antibodies to C. trachomatis elementary bodies was also investigated. 1. With regard to the immunological response at the site of infection, there was greater infiltration by T cells than by B cells. Determination of the subsets of the T cells revealed that CD8+ T cells outnumbered CD4+ T cells. In addition, among the B cell lineage, there was moderate infiltration by IgA-positive B cells, whereas the infiltration by IgM-positive B cells and IgG-positive B cells was very slight. 2. C. trachomatis-specific IgA and IgG antibodies came to be detected beginning on the 7th day of infection. When the immunological correspondence of these serum antibodies to C. trachomatis elementary bodies was investigated by western blot analysis, one band reacted with the major outer membrane protein (MOMP; 39.5 Kd), while a second band reacted with a 60-Kd protein. On the basis of these findings, it was surmised that, as the immunological response to C. trachomatis infections, the host recognizes the MOMP and a 60-Kd protein in C. trachomatis elementary bodies, thus initiating a series of immune responses. It was also surmised that, at the sites of infection, cells belonging to the T-cell lineage, especially CD8+ cells, play an important role in the host's defense mechanism against the infection by C. trachomatis.