Venom of the ant spider Lachesana tarabaevi contains a wide variety of antimicrobial peptides. Among them, a special place belongs to cyto-insectotoxins, a class of cytolytic molecules showing equally potent antimicrobial and insecticidal effects. We tested one of them, CIT 1a, for ability to suppress Chlamydia trachomatis infection. HEK293 cells were transfected with plasmid vectors harboring the cit 1a gene. Controlled expression of the transgene led to a significant decrease in C. trachomatis viability inside the infected cells. Using proteomic and transcriptomic approaches, we found alterations in protein expression patterns and identified differentially expressed genes in transfected cells. © 2012 Springer Science + Business Media, LLC.