causes granulocytic anaplasmosis, a debilitating infection that can be fatal in the immunocompromised. It also afflicts animals, including dogs, horses, and sheep. No granulocytic anaplasmosis vaccine exists. Because is an obligate intracellular bacterium, inhibiting microbe-host cell interactions that facilitate invasion can disrupt infection. The binding domains of adhesins invasion protein A (AipA), surface protein (Asp14), and outer membrane protein A (OmpA) are essential for optimal bacterial entry into host cells, but their relevance to infection is undefined. In this study, C57BL/6 mice were immunized with a cocktail of keyhole limpet hemocyanin-conjugated peptides corresponding to the AipA, Asp14, and OmpA binding domains in alum followed by challenge with The bacterial peripheral blood burden was pronouncedly reduced in immunized mice compared to controls. Examination of pre- and postchallenge sera from these mice revealed that immunization elicited antibodies against AipA and Asp14 peptides but not OmpA peptide. Nonetheless, pooled sera from pre- and postchallenge groups, but not from control groups, inhibited infection of HL-60 cells. Adhesin domain immunization also elicited interferon gamma (IFN-γ)-producing CD8-positive (CD8) T cells. A follow-up study confirmed that immunization against only the AipA or Asp14 binding domain was sufficient to reduce the bacterial peripheral blood load in mice following challenge and elicit antibodies that inhibit cellular infection These data demonstrate that AipA and Asp14 are critical for to productively infect mice, and immunization against their binding domains elicits a protective immune response.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7504939 | PMC |
http://dx.doi.org/10.1128/IAI.00106-20 | DOI Listing |
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