A new supertypic HLA class II determinant (PL2) differentially expressed with DR7, DRw11(5), DRw13(w6), DRw14(w6), DR3, and DR2 and biochemically localized to DR7 molecules

A supertypic HLA class II determinant shared by DR1 and DRw9, and crossreactive with DR2, defined by human monoclonal antibody

A human monoclonal antibody Pez.2F5, produced by a lymphoblastoid cell line, has been established in vitro by Epstein-Barr virus (EBV) transformation of B lymphocytes isolated from the blood of a volunteer immunized with allogeneic peripheral blood leukocytes (PBLs). The antibody reacted with a new supertypic determinant expressed on all lymphoblastoid cell lines homozygous for HLA-DR1, -2, and -w9. The genetic linkage of the Pez.2F5 determinant to the HLA region was demonstrated by family segregation studies. Quantitative absorption studies indicated that DR2-positive cells required more Pez.2F5 antibody for lysis, and since their absorption capacity was significantly lower than that of DR1- or DRw9-positive cells, it is likely that the Pez.2F5 determinant of the DR2 haplotype is crossreactive but not identical with the determinant found on the latter haplotypes. In addition, on a test panel of HLA-typed B lymphocytes, Pez.2F5 showed perfect correlation with DR1 and DRw9, but reacted with only a fraction of DR2-positive cells. The Pez.2F5 determinant was found to be absent from resting T lymphocytes, but its expression could be identified on IL-2-dependent T-cell lines by cytotoxicity and flow cytofluorometric analysis. By sequential immunoprecipitation and SDS gel analysis of antigens of DR1 cells it was determined that the Pez.2F5 determinant is carried by HLA class II DR molecules. Thus, the Pez.2F5 is the first described human monoclonal antibody able to immunoprecipitate HLA class II-related molecules.

An antiviral T-cell clone defines a functional supertypic specificity shared by different HLA-DR molecules from DR2-short, DRw11, and DRw13 haplotypes

An influenza virus-specific HLA class II-restricted human T4+ clone (Ij) allows us to define a new functional supertypic HLA class II specificity shared by three different haplotypes. Influenza A virus-infected antigen-presenting cells of these three haplotypes, HLA-DR2 short, DRw11, and DRw13, are able to stimulate Ij cells. The same precise viral specificity is seen in all three cases. Proliferation inhibition experiments using HLA-specific monoclonal antibodies demonstrate that HLA-DR products are involved in all cases. However, according to the DR specificity of the antigen-presenting cell, differential blockings by a series of DR-specific monoclonal antibodies suggest that the functional epitope is shared by different HLA-DR molecules. This is confirmed by two-dimensional gel analysis of the HLA-DR beta chains expressed in the three haplotypes.

A human monoclonal antibody to an HLA-DRw53 (MT3)-like epitope on class II antigens

We report the production of a lymphoblastoid human B cell line, which secretes monoclonal antibody with HLA-DRw53-like specificity. The immune lymphocytes were obtained from a patient who had been undergoing immunotherapy at Memorial Hospital with allogeneic cultured melanoma cells. The antibody producing cell line was established by transformation of immune B cells with Epstein-Barr virus and stabilized by serial selection of antibody-positive cell clusters. The cell line (R39.14) has been producing a cytotoxic antibody of IgM, kappa type during nearly two years of continuous culture. The specificity pattern was determined on a panel of HLA-DR-typed lymphoblastoid cell lines, and resembled the HLA-DRw53 specificity closely. In studies of informative families the R39.14 specificity segregated with DRw53-bearing haplotypes, which included DR-4, 7 and DRw9 antigens. The R39.14 specificity was found to be expressed in similar quantities on all antibody positive homozygous cell lines tested. Blocking experiments with monoclonal class II specific antibodies revealed R39.14 to reside on a DR molecule in close association with the determinant detected by the 109d6 mouse monoclonal antibody.