Identification of Major Histocompatibility Complex Restriction and Anchor Residues of Foot-and-Mouth Disease Virus-Derived Bovine T-Cell Epitopes

Abstract

Despite intensive research on the identification of T-cell epitopes in cattle after foot-and-mouth disease virus (FMDV) infection during the last 20 years, knowledge of major histocompatibility complex (MHC) restriction and anchor residues of such epitopes is still sparse. Therefore, as a first step, we tested lymphocytes from two experimentally FMDV serotype A24-vaccinated and -challenged cattle for recognition of FMDV-derived pentadecapeptides in proliferation assays. Two epitopes were identified: amino acid residues 66 to 80 within the structural protein 1D and amino acid residues 22 to 36 within the structural protein 1A. The latter epitope was recognized by lymphocytes from both cattle. Peptide-specific proliferation was caused by a response of CD4 ؉ T helper cells as identified by carboxyfluorescein diacetate succinimidyl ester proliferation assays. Having identified one epitope that was recognized by two cattle, we hypothesized that these animals should have common MHC class II alleles. Cloning and sequencing of DRB3, DQA, and DQB alleles revealed that both animals possessed DQA allele 22021 and DQB allele 1301 but had no common DRB3 allele. A parallel analysis of amino acid residues involved in MHC presentation by peptides with alanine substitutions showed that the amino acid residues in positions 5 and 9 within the pentadecapeptide representing the 1A epitope were important for MHC binding in both cattle. These data indicate that the epitope located on FMDV protein 1A can be presented by MHC class II DQ molecules encoded by DQA allele 22021 and DQB allele 1301 and present the first evidence of the binding motif of this particular DQ molecule.

Induction of a Cross-Reactive CD8+T Cell Response following Foot-and-Mouth Disease Virus Vaccination

“…Although a large number of peptides were screened, this was the only epitope detected, which suggests that it is immunodominant. This MHC haplotype often includes the class II allele BoLA DRB3*0701 (9), and this has previously been shown to present O/UK 790-804 (the 15-mer that includes O/UK 795-803 ) to CD4 ϩ T cells (23). Although not widely reported, overlapping CD4 ϩ and CD8 ϩ T cell epitopes have been observed previously (14,35,42).…”

“…We identified a high level of conservation within this putative epitope in representative examples of all seven FMDV serotypes. With the exception of the P1A protein which has been shown to be relatively conserved, other T cell epitopes identified in structural proteins of FMDV are highly variable in different FMDV serotypes and isolates (23).…”

“…CD4 ϩ T cell responses are suggested to play an important role in protection against FMDV, and published studies demonstrate the presence of FMDV-specific MHC class II-restricted responses in cattle and pigs (22,24). CD4 ϩ epitopes within both P1A and P1D proteins have recently been identified in cattle (23). We have recently reported the presence of FMDV-specific, MHC class I-restricted CD8 ϩ T cell responses in cattle following infection or vaccination.…”

Immune potential of a novel multiple-epitope vaccine to FMDV type Asia 1 in guinea pigs and sheep

“…The lymphocyte proliferation was analyzed by flow cytometry as described previously [11] . Briefly, heparinized whole blood was collected from the vaccinated guinea pigs groups 1-4 at 42 dpv.…”

Promising Multiple-Epitope Recombinant Vaccine against Foot-and-Mouth Disease Virus Type O in Swine

“…The proliferation of lymphocytes was analyzed by flow cytometry as described previously (19). Briefly, peripheral blood mononuclear cells (PBMC) were selected by centrifugation over Ficoll-Hypaque (density, 1.007 g/liter).…”