title: Detection of allogeneic Qa/TL and Ly specificities on murine tumor cells with IgD in tumor-regressor serum.
abstract: Serum from C3H/He mice, which show regression of MM2 tumor cells after transplantation and removal (regressor serum, RS) contains non-gammaglobulin components that cross-react with various tumor cells of mice [22, 23]. In addition to tumor cells, various allogeneic lymphocytes are also susceptible to an RS-dependent lymphocyte-mediated cytotoxic reaction. To identify tumor cell surface antigens that cause the cross-reactive host response, the serum components were analyzed by absorption of RS with allogeneic lymphocytes. RS components were found to recognize allogeneic lymphocyte antigens including Qa-2 and Ly6.2. Specificity for the Qa-2 antigen was further tested using Qa-2-congenic mice. The expression of Qa-2 antigen was detected on the surfaces of MM2 and other tumor cells derived from H-2k mice (seven among nine cell lines tested) by a membrane immunofluorescence method using a Qa-2-specific mAb. Physical characteristics of the Qa-2-specific component in RS were determined and found to differ from those of regular IgGs but to be similar to those of IgDs. Using an enzyme-linked immunosorbent assay with an IgD-specific mAb and Qa-2-lacZ fusion protein, the existence of IgD in RS with specificity for Qa-2 was confirmed. These results suggest that the RS component with Qa-2 specificity is an IgD, the specificity and physiological role of which are unknown.
authors.affiliation: Department of Tumor Biology, University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tanino
authors.forename: N
authors.initials: N
authors.lastname: Seo
authors.forename: T
authors.initials: T
authors.lastname: Okazaki
authors.forename: C
authors.initials: C
authors.lastname: Nakanishi-Ito
authors.forename: M
authors.initials: M
authors.lastname: Sekimata
authors.forename: K
authors.initials: K
authors.lastname: Egawa
mesh_terms: D000818:Animals; D000950:Antigens, Ly; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology; D000939:Epitopes; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000032:analysis* / Q000276:immunology; D007072:Immunoglobulin D / Q000032:analysis*; D007519:Isoantigens / Q000032:analysis* / Q000276:immunology; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D009374:Neoplasms, Experimental / Q000097:blood / Q000276:immunology*
chemical_list: D000950:Antigens, Ly; D000951:Antigens, Neoplasm; D000939:Epitopes; D015395:Histocompatibility Antigens Class I; D007072:Immunoglobulin D; D007519:Isoantigens; D008562:Membrane Glycoproteins; C032907:Q surface antigens; C028388:thymus-leukemia antigens