Can cognitive decline be correlated with Chlamydia pneumoniae infection, inflammatory markers and amyloid in human blood?

Christine Hammond, Ahmad B. Cader, James R. Brandt, Marisol Velez, Lauren E. Semler, Morgan Marruso, Marcus Bell, Jenayle L. Smith, Nicol E. Joseph, Katherine Galluzzi, Denah Appelt, Brian J. Balin

Research output: Other contribution


Background: Our laboratory has established a link between Chlamydia pneumoniae (Cpn) and Alzheimer’s disease (AD) using autopsied brains. In addition, we have demonstrated that human monocytes can be infected with Cpn with resultant alterations in cytokine profiles and amyloid processing. These cellular expression changes are similar to those seen in AD patients. Currently, our laboratory has an ongoing IRB approved translational research pilot study investigating infection as a biomarker for cognitive decline. The objective of this work was to identify markers related to amyloid, inflammation, and infection in patients’ samples in this study. We used multiplex arrays for the detection of amyloid and cytokines in sera and flow cytometry for Cpn intracellular infection of peripheral leukocytes in the buffy coats of patients’ blood. Methods: Tissue culture (TC) supernatants from Cpn-infected (CWL029 or AR39) THP1 cells were tested on multiplex ELISA cytokine and amyloid arrays along with their uninfected counterparts that served as controls. Further, sera from patients samples in the current study were analyzed on the MSD V-PLEX Human Proinflammatory Panel I and the MSD AB peptide panel 1 (6E10). For flow cytometry using an intracellular labeling protocol, infected THP1 monocytes were labeled with a FITC tagged anti-Chlamydia antibody and run with the appropriate controls. The buffy coats from our patient samples were prepared in a comparable manner. Comparison of the homogeneous infected monocyte population with the patients’ samples was performed to aid in identifying the infected leukocyte population within the heterogeneous buffy coat. Results: We detected both pro-inflammatory cytokines and amyloid (1-42 and 1-40) in our human sera. With flow cytometry, we were able to detect an infected leukocyte population in our patients’ samples. Conclusion: We were able to maximize our detection of cytokines and amyloid with minimal sample using the MSD detection system. This approach enhanced our reproducibility with minimal variation from sample to sample. Flow cytometry can detect Cpn in human leukocytes. Using both of these methodologies in conjunction, we may eventually be able to correlate Cpn infection in human blood to cognitive decline

Original languageAmerican English
StatePublished - May 13 2015


  • Life Sciences

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