title: Protective immunity against infection with Mycoplasma haemofelis.
abstract: Hemoplasmas are potentially zoonotic mycoplasmal pathogens, which are not consistently cleared by antibiotic therapy. Mycoplasma haemofelis is the most pathogenic feline hemoplasma species. The aim of this study was to determine how cats previously infected with M. haemofelis that had recovered reacted when rechallenged with M. haemofelis and to characterize the immune response following de novo M. haemofelis infection and rechallenge. Five specific-pathogen-free (SPF)-derived naive cats (group A) and five cats that had recovered from M. haemofelis infection (group B) were inoculated subcutaneously with M. haemofelis. Blood M. haemofelis loads were measured by quantitative PCR (qPCR), antibody response to heat shock protein 70 (DnaK) by enzyme-linked immunosorbent assay (ELISA), blood lymphocyte cell subtypes by flow cytometry, and cytokine mRNA levels by quantitative reverse transcriptase PCR. Group A cats all became infected with high bacterial loads and seroconverted, while group B cats were protected from reinfection, thus providing the unique opportunity to study the immunological parameters associated with this protective immune response against M. haemofelis. First, a strong humoral response to DnaK was only observed in group A, demonstrating that an antibody response to DnaK is not important for protective immunity. Second, proinflammatory cytokine interleukin-6 (IL-6) mRNA levels appeared to increase rapidly postinoculation in group B, indicating a possible role in protective immunity. Third, an increase in IL-12p35 and -p40 mRNA and decrease in the Th2/Th1 ratio observed in group A suggest that a Th1-type response is important in primary infection. This is the first study to demonstrate protective immunity against M. haemofelis reinfection, and it provides important information for potential future hemoplasma vaccine design.
authors.affiliation: School of Veterinary Sciences, University of Bristol, Bristol, United Kingdom Center for Clinical Studies, Vetsuisse Facility, University of Zurich, Zurich, Switzerland.
authors.forename: Chelsea A E
authors.initials: CA
authors.lastname: Hicks
authors.affiliation: Clinical Laboratory, Vetsuisse Facility, University of Zurich, Zurich, Switzerland Clinic for Small Animal Internal Medicine, Vetsuisse Facility, University of Zurich, Zurich, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Willi
authors.affiliation: Clinical Laboratory, Vetsuisse Facility, University of Zurich, Zurich, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Riond
authors.affiliation: Clinical Laboratory, Vetsuisse Facility, University of Zurich, Zurich, Switzerland Center for Clinical Studies, Vetsuisse Facility, University of Zurich, Zurich, Switzerland.
authors.forename: Marilisa
authors.initials: M
authors.lastname: Novacco
authors.affiliation: Clinical Laboratory, Vetsuisse Facility, University of Zurich, Zurich, Switzerland Center for Clinical Studies, Vetsuisse Facility, University of Zurich, Zurich, Switzerland.
authors.forename: Marina L
authors.initials: ML
authors.lastname: Meli
authors.affiliation: School of Veterinary Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Stokes
authors.affiliation: School of Veterinary Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Helps
authors.affiliation: Clinical Laboratory, Vetsuisse Facility, University of Zurich, Zurich, Switzerland Center for Clinical Studies, Vetsuisse Facility, University of Zurich, Zurich, Switzerland.
authors.forename: Regina
authors.initials: R
authors.lastname: Hofmann-Lehmann
authors.affiliation: School of Veterinary Sciences, University of Bristol, Bristol, United Kingdom S.Tasker@bristol.ac.uk.
authors.forename: Séverine
authors.initials: S
authors.lastname: Tasker
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D058491:Bacterial Load; D001769:Blood / Q000382:microbiology; D002371:Cat Diseases / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control*; D002415:Cats; D016207:Cytokines / Q000096:biosynthesis; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D018840:HSP70 Heat-Shock Proteins / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D009174:Mycoplasma / Q000276:immunology*; D009175:Mycoplasma Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D000907:Antibodies, Bacterial; D016207:Cytokines; D018840:HSP70 Heat-Shock Proteins