Chicken egg yolk anti-asialoGM1 immunoglobulin (IgY) : An inexpensive glycohistochemical probe for localization of T -antigen in human colorectal adenocarcinomas

Abstract

A egg yolk polyclonal IgY has been prepared by immunization of white leghorn chickens with small unilamellar liposomal asialoGM1. The newly prepared anti-asialoGM1 IgY has been characterized to be specific towards the terminal carbohydrate moiety of asialoGM1, and has no cross reactivity to its sialylated counterpart (ganglioside, GM1) as evidenced by immunochromatographic studies. General glycohistochemical methods along with antigen specific lectin and immunohistochemical staining using anti-asialoGM1 IgY were used to study the expression of Thomsen-Friedenreich (T-) disaccharide antigen in human colorectal adenocarcinoma tissues. The expression of T-antigen in colon cancer tissue was detected by two T-disaccharide specific probes, chicken anti-T-yolk antibody (IgY) and <i>Artocarpus integrifolia </i>lectin (AIL) and was found to be more pronounced in both the secreted mucin as well as the cytoplasmic mucin deposits. These immunochemical detection methods for T-antigen showed a weaker correlation with other glycostaining methods using, alcian-blue/periodic acid-Schiff (AB-PAS) and high iron diamine (HID). However, a general enzymatic staining for galactose and galactosamine containing glycoconjugates, by galactose oxidase-Schiff method, showed a good correlation with T-antigen detection. While the T-beta specific anti-asialoGM1 could localize T-antigen in 11 of 13 (84%) human colorectal adenocarcinoma tissue sections tested, the T-alpha specific AIL could localize the T-antigen in only 6 of the tissues (46%). These observations confirm previously reported findings, of the prevalence of T-beta conformation in colon cancer, that binds significantly more with the anti-asialoGM1 IgY than with the T-alpha specific AIL. Hence, both anti -T IgY and the AIL immunohistochemical probes may have useful diagnostic value because of the ease of preparation and cost effectiveness, but the T-beta specific anti-asialoGM1 probe (IgY) would have a better prognostic value in colon adenocarcinomas.