Tallmadge RL, Miller SC, Parry SA, Felippe MJB. Antigen-specific immunoglobulin variable region sequencing measures humoral immune response to vaccination in the equine neonate.
PLoS One 2017;
12:e0177831. [PMID:
28520789 PMCID:
PMC5433778 DOI:
10.1371/journal.pone.0177831]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 05/03/2017] [Indexed: 12/16/2022] Open
Abstract
The value of prophylactic neonatal vaccination is challenged by the interference of passively transferred maternal antibodies and immune competence at birth. Taken our previous studies on equine B cell ontogeny, we hypothesized that the equine neonate generates a diverse immunoglobulin repertoire in response to vaccination, independently of circulating maternal antibodies. In this study, equine neonates were vaccinated with 3 doses of keyhole limpet hemocyanin (KLH) or equine influenza vaccine, and humoral immune responses were assessed using antigen-specific serum antibodies and B cell Ig variable region sequencing. An increase (p<0.0001) in serum KLH-specific IgG level was measured between days 21 and days 28, 35 and 42 in vaccinated foals from non-vaccinated mares. In vaccinated foals from vaccinated mares, serum KLH-specific IgG levels tended to increase at day 42 (p = 0.07). In contrast, serum influenza-specific IgG levels rapidly decreased (p≤0.05) in vaccinated foals from vaccinated mares within the study period. Nevertheless, IGHM and IGHG sequences were detected in KLH- and influenza- sorted B cells of vaccinated foals, independently of maternal vaccination status. Immunoglobulin nucleotide germline identity, IGHV gene usage and CDR length of antigen-specific IGHG sequences in B cells of vaccinated foals revealed a diverse immunoglobulin repertoire with isotype switching that was comparable between groups and to vaccinated mares. The low expression of CD27 memory marker in antigen-specific B cells, and of cytokines in peripheral blood mononuclear cells upon in vitro immunogen stimulation indicated limited lymphocyte population expansion in response to vaccine during the study period.
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