Antigen-specific immunoglobulin variable region sequencing measures humoral immune response to vaccination in the equine neonate

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.

Vaccination of foals with a modified live, equid herpesvirus-1 gM deletion mutant (RacHΔgM) confers partial protection against infection

“…There is some evidence of variation in antigenspecific immune responses with age, particularly very young foals. For example, foals vaccinated with keyhole limpet haemocyanin at 3 days old, followed by booster vaccination showed a diverse immunoglobulin repertoire and the ability to switch isotype as measured by sequencing of the B cell immunoglobulin variable region [56]. Three-month-old foals vaccinated twice intra-musculary at 3 week intervals with a killed cattle respiratory viral vaccine and adjuvant, mounted lower antigen specific proliferation and humoral immune responses compared with adults [57] suggesting that the adaptive immune response to this antigen is still immature at 3-4 months of age.…”

Exploiting V-Gene Bias for Rapid, High-Throughput Monoclonal Antibody Isolation from Horses

“…To this end, several studies have focused on characterising the immunoglobulin repertoire of the horse [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Antibodies are composed of heavy (IgH) and light (Igλ or Igκ) chains, which can be further divided into constant and variable domains.…”

Zinc Sulphate Turbidity as a Screening Test of Passive Transfer of Immunity in Newborn Foals

“…Although newborn foals are immunocompetent, the regulation of immunity and responses to pathogens or vaccination are markedly different between foals and adult horses [22,32,33]. The immaturity of the immune system determine that foals must acquire protection against environmental opportunistic pathogens by colostrum ingestion [19,20].…”