Recombinant protein CPSIT_0846 induces protective immunity against Chlamydia psittaci infection in BALB/c mice

Abstract

Chlamydia psittaci is an obligate intracellular bacteria that causes respiratory disease in poultry and humans. Currently, there are no licensed vaccines against chlamydial infection in humans. The transmembrane head protein CPSIT_0846 of C. psittaci is a putative member of the larger Inc protein family. In this study, we investigated immunogenicity and protective efficacy of the recombinant CPSIT_0846 protein in BALB/c mice. Mice immunized with CPSIT_0846 developed strong T-lymphocyte responses that were recalled by the immunogen CPSIT_0846 in an in vitro restimulation assay. These T cells displayed a strong Th1-biased cytokine profile with high levels of IFN-γ. At the same time, a strong humoral immune response was also detected in the immunized mice with high titers of Chlamydia psittaci-specific serum IgG antibodies. More importantly, the robust immune responses correlated well with significantly reduced chlamydial burden and inflammatory pathology in the mouse lungs upon an airway challenge infection. The above results together suggest that the CPSIT_0846 protein may be a potential vaccine candidate antigen for inducing protection against C. psittaci infection and disease in the airway.

Immunization with Chlamydia psittaci plasmid-encoded protein CPSIT_p7 induces partial protective immunity against chlamydia lung infection in mice

“…Immunized and control mice were anesthetized with ether and infected intranasally (i.n.) with 30 μl of 5 × 10 5 IFUs C. psittaci in a sucrose-phosphate-glutamic acid (SPG) buffer 2 weeks after the last immunization to evaluate the protective efficiencies [18,19]. All mice were weighed before and 3, 7, and 10 days after challenge.…”

The Hypothetical Inclusion Membrane Protein CPSIT_0846 Regulates Mitochondrial-Mediated Host Cell Apoptosis via the ERK/JNK Signaling Pathway

“…Recombinant CPSIT_0846 protein was prepared as formerly described ( Ran et al, 2017 ). Fusion proteins were purified using Ni-nitrilotriacetic acid (NTA) beads (QIAGEN Inc., Germany), and concentrated with a BCA Protein Assay Kit (Dojindo, Tokyo, Japan).…”

“…CPSIT_0846 is also a member of the transmembrane head (TMH) protein family, which shares 84% homology with the TMH family protein secreted by C. abortus . We previously found that CPSIT_0846 not only promoted the production of tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, and IL-6 in human monocytic THP-1 cells in vitro , but also induced a strong humoral and cellular immune response in mice ( Wu et al., 2016 ; Ran et al., 2017 ). Therefore, we speculate that this protein may be closely related to the pathogenic mechanism of C. psittaci .…”

Diagnóstico, prevención y control de enfermedades causadas por Chlamydia en pequeños rumiantes. Revisión

“…Los resultados de dicho estudio revelaron que la ELISA-PmpD-N tuvo una sensibilidad y especificidad del 97.9 %, 100 % respectivamente; además, no hubo reacción cruzada con sueros positivos para otros patógenos aviares. Los resultados concluyeron que esta fracción proteínica (PmpD-N) puede ser empleada como antígeno para el diagnóstico de infecciones por C. psittaci en aves (60) . Cabe destacar que todos los estudios se han realizado en C. psittaci de origen aviar; sin embargo, dado que C. psittaci está genéticamente relacionada con C. abortus (61) , con estas evidencias se puede contemplar la idea de enfocar los estudios en la variante que afecta a los pequeños rumiantes.…”