Proteomic identification of immunodominant chlamydial antigens in a mouse model

Abstract

Chlamydia trachomatis is the most common bacterial sexually transmitted pathogen in the world. To identify new vaccine candidates a protein microarray was constructed by expressing the open reading frames (ORFs) from Chlamydia mouse pneumonitis (MoPn). C57BL/6, C3H/HeN and BALB/c mice were immunized either intranasally or intravaginally with live MoPn elementary bodies (EB). Two additional groups were immunized by the intramuscular plus subcutaneous routes with UV-treated EB, using CpG and Montanide as adjuvants to favor a Th1 response, or Alum, to elicit a Th2 response. Serum samples collected from the three strains of mice were tested in the microarray. The array included the expression of 909 proteins from the 921 ORFs of the MoPn genome and plasmid. A total of 530 ORFs were recognized by at least one serum sample. Of these, 36 reacted with sera from the three strains of mice immunized with live EB. These antigens included proteins that were previously described as immunogenic such as MOMP and HSP60. In addition, we uncovered new immunogens, including 11 hypothetical proteins. In summary, we have identified new immunodominant chlamydial proteins that can be tested for their ability to induce protection in animal models and subsequently in humans.

Defining Species-Specific Immunodominant B Cell Epitopes for Molecular Serology of Chlamydia Species

“…substantially to ϳ72 known immunodominant chlamydial proteins, information that had been accessible from classical (74)(75)(76)(77)(78)(79)(80)(81)(82) as well as several recent proteome-wide comprehensive studies (58)(59)(60)(61)(62)(63)(64)(65)(66). We tested peptides from a total of 64 proteins, mainly at polymorphic regions for species or strain specificity, but also at conserved regions for multispecies or genus specificity (Table 1).…”

“…To identify species-specific B cell epitopes, we first identified and ranked 72 immunodominant proteins among all chlamydial proteomes (46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57), based on published data (58)(59)(60)(61)(62)(63)(64)(65)(66)(74)(75)(76)(77)(78)(79)(80)(81)(82). These protein sequences of all nine chlamydial species, and of serovars among species, were first aligned in the freeware Jalview (83) by use of the MUSCLE algorithm and weights for amino acid substitutions based on the Blosum62 AA substitution matrix (83)(84)(85).…”

“…This goal is now facilitated by the availability of complete genome sequences of all chlamydial species and of many serovars of some species (46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57), by proteome-wide mapping of immunodominant proteins in several chlamydial species (58)(59)(60)(61)(62)(63)(64)(65)(66), and by advanced computational tools for B cell epitope discovery (39)(40)(41)(42). Using a murine respiratory infection model, we report here peptide-based molecular serology for nine Chlamydia spp.…”

Whole genome identification of C. trachomatis immunodominant antigens after genital tract infections and effect of antibiotic treatment of pigtailed macaques

“…The C. trachomatis serovar D (UW-3/Cx; ATCC) genomic specific PCR primers were designed using 20 bp of the gene-specific sequence and 33 bp of adapter sequences [10, 11, 16, 17]. The adapter sequences were designed to be homologous to the cloning site of the linearized T7 expression vector pXT7 and allowed the PCR products to be cloned by homologous recombination in DH5α E. coli cells.…”

CPAF selectively degrades chlamydial T cell antigens for inhibiting antigen presentation

“…In this study, BALB/c were selected, and purified chlamydia EBs were used for vaccination [38]. After confirmation of the presence of positive chlamydia antibodies, the mice were sacrificed and the spleens subjected to CD4+ T cells isolation.…”