Jacques Bara

Characterization of the binding specificity ofAnguilla anguilla agglutinin (AAA) in comparison toUlex europaeus agglutinin I (UEA-I)

Using immunochemical and immunohistochemical methods, the binding site ofAnguilla anguilla agglutinin (AAA) was characterized and compared with the related fucose-specific lectin fromUlex europaeus (UEA-I). In solid-phase enzyme-linked immunoassays, the two lectins recognized Fucα1-2Galβ-HSA. AAA additionally cross-reacted with neoglycolipids bearing lacto-N-fucopentaose (LNFP) I [H type 1] and II [Lea] and lactodifucotetraose (LDFT) as glycan moieties. UEA-I, on the other hand, bound to a LDFT-derived neoglycolipid but not to the other neoglycolipids tested. Binding of AAA to gastric mucin was competitively neutralized by Lea-specific monoclonal antibodies. UEA-I binding, on the other hand, was reduced after co-incubation with H type 2- and Ley-specific monoclonal antibodies. According to our results, AAA reacts with fucosylated type 1 chain antigens, whereas UEA-I binds only to the α1-2-fucosylated LDFT-derived neoglycolipid. In immunohistochemical studies, the reactivity of AAA and UEA-I in normal pyloric mucosa from individuals with known Lewis and secretor status was analysed. AAA showed a broad reaction in the superficial pyloric mucosa from secretors and non-secretors, but AAA reactivity was more pronounced in Le(a+b-) individuals. On the other hand, UEA-I stained the superficial pyloric mucosa only from secretor individuals. A staining of deep mucous glands by the lectins was found in all specimens. Both reacted with most human carcinomas of different origin. Slight differences in their binding pattern were observed and may be explained by the different fine-specificities of the lectins.

Heterogeneity of the ABH antigenic determinants expressed in human pyloric and duodenal mucosae

We defined the chemical structure and the genetic control of the various A or B determinants expressed by pyloric and duodenal epithelial cells by indirect immunofluorescent staining using monoclonal anti-A or anti-B reagents that recognize only certain variants of A or B antigenic determinants.Some mucous cells in pyloric and Brünners glands express AY or BY antigens whereas other mucous cells in the same glands express only the Y antigen. Absorptive and goblet cells of the duodenal villi and Lieberkühn glands express mono- and difucosylated A or B structures, mainly of type 1. The pyloric surface epithelium expresses mono- and difucosylated, type 1 and type 2, A or B structures. In addition, A or B antigens, with a so far undefined structure are found in the pyloric surface mucosae of non-secretor individuals.

The distribution of mucins, carcinoembryonic antigen, and mucus-associated antigens in endocervical and endometrial adenocarcinomas.

The presence and distribution of mucins, carcinoembryonic antigen (CEA), and mucus-associated antigens M1, M2, and M3 were investigated in 22 normal endocervices, 25 normal endometria, 25 endocervical adenocarcinomas, and 32 endometrial adenocarcinomas to determine their contribution in the differential diagnosis of endocervical and endometrial adenocarcinoma. Sections of formalin-fixed paraffin-embedded tissues were stained with conventional histochemical stains such as d-PAS and Alcian blue to investigate the distribution of mucins. For the demonstration of CEA and the mucus-associated antigens an indirect immunoperoxidase technique was used. In the present study d-PAS and Alcian blue stains, as well as immunohistochemistry of CEA, did not contribute to the discrimination between adenocarcinomas of the endocervix and endometrium. Immunohistochemistry of mucus-associated antigens showed a positive reaction of M3 in the majority (68%) of the endocervical carcinomas. In contrast, if foci of endocervical-type metaplasia were excluded, M3 was absent in tumor cell cytoplasm of endometrial adenocarcinomas. Furthermore, the expression of M2 without the presence of the other mucus antigens in tumor cell cytoplasm, as seen in 24% of the endometrial adenocarcinomas, was never found in endocervical adenocarcinomas.

Aneuploidy and Expression of Gastric-Associated Mucus Antigens M1 and CEA in Colorectal Adenomas

A series of 55 flow cytometric characterized colorectal adenomas was analyzed with four different monoclonal antibodies (Mabs) for the occurrence of M1 antigens (associated with gastric fucomucins) and one Mab for carcinoembryonic antigen (CEA). The antigens were detected with an indirect immunoperoxidase technic on paraffin sections after pretreatment with pronase for M1 antigens and without pretreatment for CEA. The staining pattern revealed different correlations with the various parameters, i.e., size, histologic type, atypia, and ploidy of the adenomas. Especially the cytoplasmic staining of anti-M1, Mab (1-13 M1) correlated well with aneuploidy (R = 0.43; P less than or equal to 0.001) and with the DNA index (R = 0.34; P less than or equal to 0.01). Staining of the anti-CEA Mab only correlated with the size of the adenomas (R = 0.29; P less than or equal to 0.03). It is concluded that the immunoreactivity of Mab (1-13 M1), which significantly correlated with aneuploidy, may be associated with malignant transformation in the adenoma-carcinoma sequence.

Colonic and gastric mucus-associated antigens: A comparative immunohistological study in precancerous and cancerous rat intestinal mucosa

Gastric M1 antigens were previously shown to be oncofetal markers for the colon in man and in the rat. They were observed very early during carcinogenesis in goblet cells of precancerous colonic mucosa; using an immunohistological method, we found that M1 were produced in 68% (41/60) of colonic adenocarcinomas and in 33% (21/63) of duodenal adenocarcinomas. M3C antigen has been described as being associated with human colonic mucus; in the rat it is restricted to the proximal colon. We found that M3C was produced in 91% (55/60) of colonic adenocarcinomas and in 15% (8/53) of duodenal adenocarcinomas. Before tumor appearance, M3C was sometimes expressed by goblet cells of the distal colon. We could not find it during fetal life. We have concluded that mucus-associated antigens can characterize modifications in cell differentiation in rat colonic carcinomas.