Open AccessAntibody activities in hyperimmune plasma against the Rhodococcus equi virulence -associated protein A or poly-N-acetyl glucosamine are associated with protection of foals against rhodococcal pneumonia
Author(s) -
Susanne K. Kahn,
Colette CywesBentley,
Glenn P. Blodgett,
Nathan M Canaday,
Carly E Turner-Garcia,
Mariana Vinacur,
Sophia C Cortez-Ramirez,
Patrick Sutter,
Sarah C Meyer,
Angela I. Bordin,
Daniel R. Vlock,
Gerald B. Pier,
Noah D. Cohen
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0250133
Subject(s) - rhodococcus equi , pneumonia , medicine , antibody , subclinical infection , population , immunology , staphylococcus aureus , microbiology and biotechnology , virulence , biology , bacteria , biochemistry , genetics , environmental health , gene
The efficacy of transfusion with hyperimmune plasma (HIP) for preventing pneumonia caused by Rhodococcus equi remains ill-defined. Quarter Horse foals at 2 large breeding farms were randomly assigned to be transfused with 2 L of HIP from adult donors hyperimmunized either with R . equi (RE HIP) or a conjugate vaccine eliciting antibody to the surface polysaccharide β-1→6-poly- N -acetyl glucosamine (PNAG HIP) within 24 hours of birth. Antibody activities against PNAG and the rhodococcal virulence-associated protein A (VapA), and to deposition of complement component 1q (C՛1q) onto PNAG were determined by ELISA, and then associated with either clinical pneumonia at Farm A (n = 119) or subclinical pneumonia at Farm B (n = 114). Data were analyzed using multivariable logistic regression. Among RE HIP-transfused foals, the odds of pneumonia were approximately 6-fold higher (P = 0.0005) among foals with VapA antibody activity ≤ the population median. Among PNAG HIP-transfused foals, the odds of pneumonia were approximately 3-fold (P = 0.0347) and 11-fold (P = 0.0034) higher for foals with antibody activities ≤ the population median for PNAG or C՛1q deposition, respectively. Results indicated that levels of activity of antibodies against R . equi antigens are correlates of protection against both subclinical and clinical R . equi pneumonia in field settings. Among PNAG HIP-transfused foals, activity of antibodies with C՛1q deposition (an indicator of functional antibodies) were a stronger predictor of protection than was PNAG antibody activity alone. Collectively, these findings suggest that the amount and activity of antibodies in HIP ( i . e ., plasma volume and/or antibody activity) is positively associated with protection against R . equi pneumonia in foals.