DNA vaccination with the major outer-membrane protein gene induces immunity to Chlamydia trachomatis (mouse pneumonitis infection

The efficacy of DNA vaccination for prevention of Chlamydia trachomatis infection was studied using the murine model of pneumonia induced by the mouse pneumonitis (MoPn) isolate of C. trachomatis. Intramuscular DNA immunization with two chlamydial genes, one that encodes the major outer-membrane protein (MOMP) and one that encodes a cytoplasmic enzyme (cytosine triphosphate [CTP] synthetase) were tested. The MOMP DNA vaccine but not the CTP synthetase DNA vaccine generated significant delayed-type hypersensitivity and serum antibodies to MoPn elementary bodies and reduced the peak growth of MoPn by 100-fold following lung challenge infection. MOMP DNA immunization suggests a new approach to vaccine development for preven-tion of human chlamydial infection. DNA vaccination is a novel approach for generating protec- cine would clearly be desirable because chlamydial infections are significant causes of infertility and blindness and are ative immunity against infectious diseases [1]. Unlike protein-or peptide-based subunit vaccines, DNA vaccination provides prevalent cofactor facilitating the transmission of human immu-nodeficiency virus type 1. Protective immunity to C. tracho-protective immunity following endogenous expression of for-eign proteins by host cells, thus allowing the presentation of matis is effected through cytokines released by Th1-like CD4 lymphocytes and by local antibody in mucosal secretions and isantigen to the immune system in a manner that may be mor