Recall of original serologic response after challenge with homologous and heterologous Chlamydia trachomatis serovars

Chlamydia trachomatis serovar-specific major outer membrane protein (MOMP) antigens are important targets of immune neutralization in vitro, and natural immunity to infection is associated with serovar specificity. Reinfection, often by different serovars, plays an essential role in chlamydial disease pathogenesis. By use of a murine model, the anamnestic serologic response was characterized following priming and challenge inoculations using 6 different serovars. The serologic response was evaluated using synthetic peptides representing MOMP variant segments (VS) 1, 2, 3, and 4 antigenic regions for each of the 6 serovars. One year after a single priming inoculation, challenge with the same serovar resulted in serologic responses to homologous VS1 peptides. After challenge with a different serovar, anti-VS1 serologic responses were often elicited with specificity to both the priming serovar and the challenge serovar, The recall of serologic response to the original serovar was typically dependent upon the antigenic relationship of the 2 serovars.