Epitope mapping of epidermal growth factor receptor (EGFR) monoclonal antibody and induction of growth-inhibitory polyclonal antibodies by vaccination with EGFR mimotope

Abstract

One of the proposed approaches in cancer therapy is to induce and direct the patient's own immune system against cancer cells. In this study, we determined the epitope mapping of the rat anti-human epidermal growth factor receptor (EGFR) monoclonal antibody ICR-62 using a phage display of random peptide library and identified a 12 amino acids peptide, which was recognized as a mimotope. The peptide was synthesized and conjugated to bovine serum albumin (BSA) as carrier protein (P-BSA). We have shown that ICR-62 can react specifically with P-BSA as well as native EGFR. Two rabbits were immunized either by BSA or P-BSA and the rabbits IgGs were purified and examined for binding to the antigens, mimotope and the EGFR protein purified from the EGFR overexpressing A431 cell line. We showed that the rabbit IgG generated against the mimotope is capable of inhibiting the growth of A431 cells by 15%, but does not have any effect on the growth of EGFR-negative MDA-MB-453 cell line in vitro. Our results support the need for further investigations on the potential of vaccination with either mimotope of the EGFR or epitope displayed on the surface of phage particles for use in active immunotherapy of cancer.

Cancer immunotherapy by a recombinant phage vaccine displaying EGFR mimotope: anin vivostudy

“…These experiments were followed by animal immunization using peptide-BSA conjugate which confirmed cross-reactivity with EGFR of the anti-mimotope antibodies. The produced antibodies also exerted growth inhibitory effects on EGFR expressing cell line 16 .…”

In Silico and in vitro Evaluation of a Recombinant Fusion Peptide as a Novel Candidate Vaccine for EGFR-positive Tumors

“…Peptide vaccination for cancer is one of the most main procedures in this field. Lots of peptides have been introduced as cancer vaccine like EGFR mimotope 14 , extra cellular domain of EGFR 12 , chemically synthesized peptide 17 and so on. In this study, we considered in silico construction of a new fusion peptide consisted of EGFR mimotope and L2 domain of EGFR.…”

“…The high affinity against the antibodies showed that EM-L2 peptide could be a suitable candidate for EGFR-positive tumors. Moreover, Navari et al evaluated the EGFR mimotope/ICR62 reaction 14 . Our findings confirmed the EM-L2 affinity toward anti EGFR antibodies.…”

“…Previously, we mapped ICR-62 (an EGFR monoclonal antibody) and reported an EGFR mimotope which was chemically synthesized and its conjugate with BSA was injected into rabbits. It was reported that rabbit IGs against mimotope showed anti EGFR activity 14 . Ramirez et al showed that using an appropriated adjuvant like FA (freund adjuvant) it would be feasible to stimulate mice immune system to produce anti EGFR antibody against murine extra cellular domain of EGFR 12 .…”

Induction of anti-EGFR immune response with mimotopes identified from a phage display peptide library by panitumumab

“…In addition to the peptide vaccines derived from the amino acid sequence of antigens, peptide mimotopes, which are composed of amino acids different from those of native antigens, can mimic antigen-antibody binding sites structurally [5–7]. Active immunization with mimotopes would elicit antibodies against the corresponding epitopes.…”