Louis, MO, USA). cells. Conclusion The 21 kDa protein detected by clone R23.1 and clone R24.1 mabs is a novel membrane-associated protein that may be AG-13958 a potential marker for the diagnosis and targeted therapy of HL and aggressive T and B cell NHL. Background Hodgkin and Reed-Sternberg (HRS) cells of HL and the neoplastic cells of Anaplastic Large Cell Lymphoma (ALCL) AG-13958 constitutively express CD30 [1]. CD30 has been characterized as a 120 kDa surface phosphorylated glycoprotein, and is a member of the tumour necrosis factor/nerve growth factor receptor (TNF/NGFR) family [2]. Currently available antibodies against CD30 recognize one of three clusters designated as A, B, and C. For instance, antibodies Ki-2, Ki-4, Ki-5, Ki-7, Ber-H2, HRS-1 and HRS-4 recognize cluster A, antibodies Ki-1, Ki-6, and M67 recognize cluster B, and antibodies Ki-3, M44, HeFi-1 and C10 recognize cluster C[3]. CD30, however, does not have disease-specificity, as it is an activation-associated antigen. It is expressed by activated T and B cells, HTLV-I or HTLV-II transformed T cells, EBV-transformed B cells [4], ALCL [5], mediastinal diffuse large B cell lymphoma [6], other diffuse large B cell lymphomas [7], follicular centre cell lymphoma [8], and testicular embryonal carcinoma cells [9]. The identification of cell surface molecules that are not activation-associated markers, and have specificity for HRS cells thus remains a desirable goal. To this end, we have developed and characterized 2 novel AG-13958 monoclonal antibodies, R23.1 and R24.1, that recognize a 21 kDa molecule expressed by H/RS and ALCL cells, but not by phytohemagglutinin (PHA) activated CD30+ T lymphocytes. Results Reactivity of R23.1 and R24.1 against CD30+ and CD30- cell lines The two antibodies were reactive against cell surface antigens of almost all CD30+ cell lines as assessed by FACS analysis. Of 14 CD30+ cell lines, R23.1 and R24.1 labelled 12 (86%) (Table ?(Table1).1). Of 14 CD30 unfavorable cell lines, none was labelled by either R23.1 or R24.1 (Table ?(Table2).2). Examples of cell surface labelling of HL cell collection KMH2 by the two antibodies as well as anti-CD30 antibody BerH2 are shown in Figure ?Physique1.1. Relative antigen densities as indicated by the position of the fluorescence peak channel tended to vary with each antibody as well as each cell collection (data not shown). Table 1 Reactivity with CD30+ cell lines

Cell LineIsotype ControlCD30R23.1R24.1

KMH2 (Hodgkin lymphoma)-+++HDLM (Hodgkin lymphoma)-+++L428 (Hodgkin lymphoma)-+++JB (Anaplastic large cell lymphoma)-+++DEL (Anaplastic large cell lymphoma)-+++SR786 (Anaplastic large cell lymphoma)-+++K562 (Erythroleukemia)-+++HPB/ALL (T lymphoblastic lymphoma)-+++OCI Ly1 (Large B cell lymphoma)-+–OCI Ly3 (Large B cell lymphoma)-+++OCI Ly19 (Large B cell lymphoma)-+–OCI Ly12 (Peripheral T cell lymphoma)-+++OCI Ly17 (Peripheral T cell lymphoma)-+++ Open in a separate window Table 2 Reactivity with CD30 negative cell lines

Cell LineIsotype ControlBerH2R23.1R24.1

U937—-Jurkat (T acute lymphoblastic leukemia—-HL60—-Raji (Burkitt lymphoma)—-Daudi (Burkitt lymphoma)—-OCI Ly7 (Large B cell lymphoma)—-OCI Ly18 (Large B cell lymphoma)—-OCI M2 (Erythroleukemia)—-AML-2 (Acute myeloid leukemia)—-AML-4 (Acute myeloid leukemia)—-OCI Ly13.1 (Peripheral T cell lymphoma)—-OCI Ly13.2 (Peripheral T cell lymphoma)—-OCI Ly8 (B Immunoblastic lymphoma)—-OCI Ly2 (Large B cell lymphoma)—- Open in a separate window Open in a separate window Determine 1 FACS analysis of Hodgkin cell collection KMH2 after labeling with clone R23.1, clone R24.1, or CD30 mabs. Blue lines indicate Rabbit polyclonal to CapG isotype control binding. Solid reddish curves indicate mab binding. Both antibodies labelled cytoplasmic antigens in all Hodgkin and ALCL cell lines tested (Table ?(Table3).3). Examples are shown in Figure ?Physique2.2. The pattern was generally diffuse in both mononuclear and multinucleated forms of the cells, though strong staining was observed around the cell membrane. The staining.