Recognition by a natural cytotoxic antibody of lactoneotetraglycosyl ceramide as an antigenic molecule in a syngeneic rat fibrosarcoma

Abstract

Conventionally bred rats possess in their sera an NA which has a cytotoxic effect on a tumor cell line (KMT-17) derived from a fibrosarcoma induced by 3-methylcholanthrene and which can be absorbed by normal rat tissues. We have succeeded in purifying a glycosphingolipid as an antigen reactive to NA. GSLs isolated from the tumor cells were separated into neutral and acidic fractions. The former fraction was judged to be antigenic as detected by its capacity to absorb NA. The antigenic fraction was further separated into 7 fractions (Frs. A to G) by silicic acid chromatography. The antigenic activity was detected in only Frs.D and E, although Fr.D was a more potent antigen than Fr.E. Chemical and immunochemical analyses showed that both fractions are composed of lactoneotetraglycosyl ceramide (paragloboside), Gal(beta 1-4)GlcNAc(beta 1-3)Gal(beta 1-4)Glc(beta 1-1)ceramide, and that the more active GSL, Fr.D, contains larger amounts of long fatty-acid chains. Inhibition studies using disaccharides and monosaccharides indicated that a N-acetyllactosamine moiety, Gal(beta 1-4)GlcNAc, of the GSL is a specific site of NA. These results suggest that paragloboside is an NA antigen and that a sugar chain portion of this GSL is required for defining specificity while the ceramide portion plays a role in potentiating the antigenicity of this GSL antigen for NA.

Application of Monoclonal Antibody KH2 against Lactosyl and Neolactotetraosyl Ceramide to Immunohistochemical Study of Human Cancers

“…A natural antibody against nLcOse4 ceramide has been found in rats [15], hamsters [16] and humans [17]. Although the immu nogen has not been precisely revealed as yet, some bacterial or viral infections may play a role in the expression of the N-acetyl lactosamine moiety by means of inflammatory reactions [17], On this point, it is of interest to note that the antigen was expressed by neuraminidase treatment in the endothelial cells of blood vessels.…”

Monoclonal antibodies to glycolipids of the isoglobo‐series detect tumor‐associated antigens in rats

“…Antibody responses to the ganglioside GM, have been induced in melanoma patients using purified glycolipid (Livingston et al, 1987) or a preparation from melanoma cells (Tai er al., 1985). Monoclonal and natural antibodies to neutral glycolipids, globotriaosylceramide (Gala 1 -4GalP 1 -4GlcP 1 -Cer) and lactoneotetraosylceramide (Galfil-4GlcNAc~l-3Gal~l-4Glc~l-Cer) that are found in 3methylcholanthrene-induced rat fibrosarcomas (and widely distributed in normal tissues) have been described (Ito et al, 1984;Takimoto et al, 1985).…”