Monoclonal antibodies identifying a novel T-Cell antigen and Ia antigens of human lymphocytes

T90/44 (9.3 antigen). A cell surface molecule with a function in human T cell activation

“…Comparative immunoprecipitation studies had revealed that both the class ί restneted CTL and the class II restneted Μ leprae activated T|, cell clones express sigmficintly larger amouts of T90/44 than resting PBL It was thei efore postulated that Γ90/44 cxpiession is mduced in activated Τ cclls Toinvcs tigate this hypothesis PBL or two unreiated donors were eul tured in the presence of optimally activating concentrations of PHA and (afterday 3) of IL 2 Aliquots of ceils were surface lodmated at day 0 3 5 and 7 of PHA activition T90/44 together with other representative surface intigens were irnmunopreupitated from ceü lysates the respective bands weie cut trom SDS gels and the mcorporated ladiolabel w is counted it WdS found that the iadioaaivity per cell which is incorpoiated tnto Ύ90/44 jncreased reguJarJy from day 0 to day 7 by factors of 6-10 (F-ig 4) Whereas similar results were observed with DRa β and DQa β and with the transferrm reeeptor less pronounced increases were found with the LFA 1 or class I antigens The expression of still other surface anti gens was not affected by the cell acttvation for example thc rad/oiabel mcorporated into the 4 3 dntjgen [J6] remaincd practicaliy constant throughout the whole activation penod (Fig 4) The suifacc lodination of cells and the lmmunopreopitations were cirncd out under cartftilly standardized copditions thty 4 Mitogcmc iction of 9 3 mAb (^ 6 ind 1 4 u^,/ml tnlibud)) inti Π mAb nid PH \ in LUIIUKS ol I'BI (S Χ II) CLIK \\U1) 1\ inph I (5 χ K) J cells/wcll) punficd by soiting out monocytic cclls Iroin PBL onllu 1 ACS IV ccll SGULT ilu s imL punlicd l\mp!ioc\tLs (s χ Κ! well) to which-mtologous nridiätcd PBL (S χ 10 iclK/uül) uorc iddui b ILL iml irr uli ited PB1 (S χ 10' L dls u Jl) The number ot the diffcrent 1 edi suttice mtieLiis ilnonjh which the intracellul u atti\ ititin ρ ithw i\ cm Ix idiiies^ed and which thereloie um tcti\ itc I cclls inlo piohlci ition is small At piestnt the Τι/Ή umipltx uul !ΐκ ΠΙ mtme.il iri known to belong to Ihis cl iss oi CLII siui KC molet-ults [ 1 ί| The present results toetthci vvith the, prcvious iindin^s on the functional effecls of 9 λ mAb ["> 7 ^j k i\e httk doubt th it Γ ι )()/44 also tan recene mitogcnic infomi ition 1 ( )0 44 tonn ill\ nKets the csscnti il (.nteii ι \\liieh dehnt ι leceptoi molnuk it is exprtssed it the ccil smi in.…”

“…Μ leprae antigens were kindly provided by Dr Μ Abe (Nat Inst Leprosy Research, Fokyo Japan) and by Dr R C Good (Centre for Infectious Diseases, CDC, Atlanta GA) Both preparations consisted of bacilii isolated from human tepromas aecording to Dharmendia's proceduie [14J with siight modifications The end concentrations of the fnsl preparation m the cultures are given in μg/ml, whereas those of the second preparation are txpressed as final diiution in the cultures The 9 3 mAb was onginaily prepared by Hansen et al [4] For the present expenments, the 9 3 mAb was bought from New Tngland Nuclear (Boston, MA), it was punfied by protein Α aifinity chromatography and found to bc homogeneous by SDS gel electrophoresis Other monoclonai antibodies used were directed against ciass I majoi histocom patibihty antigen, 9455 SA/BRL, W6/32, B9 12 1 (couitesy of Dr Β Mahssen), ßi-microglobulm, Bl 1 G 6 (courtesy of Di Β Mahssen), T3 antigen W132(RIV Bilthoven), T4, RIV6 Γ8, IK18, transferrm reeeptor, 6 Κ 22 1, I F Α 1, 8 3 14 1, DR, B8 11 2 (courtesy Dr Β Mahssen), DQ, SP V L3 8 (courtesy Dr Η Spits), 3Al-hke determmant, 64 5 1 and Ob,, PdV 10 2…”

“…T90/44 IS a cell surface antigen which IS present on human Τ cells of the helper and cytotoxic subsets and which binds the 9 3 monoclonal antibody (9 3'mAb) It is expressed in the form of 90-kDa disulfide-bonded dimers of a 44-kDa polypeptide and of free 44-kDa subumts The function of T90/44 was investigated in a senes of Τ cell function assays 9 3 mAb was found to mhibit the activation of class II-restncted cloned Τ helper cells denved from leprosy patients and reactive with Μ leprae antigens The Inhibition was first found at 1-10 ng/ml 9 3 mAb and regularly increased with the antibody concentration The extent of the Inhibition vaned among different Τ cell clones in proportion to the respective different levels of T90/44 expression at their cell surface The prohferative responses of penpheral blood lymphocytes (PBL) to punfied protein derivative of Μ tubertulosis (PPD) and tetanus toxoid were enhanced by the 9 3 mAb resulting in up to 20-30-fold increase of [ 3 H]-thymidme incorporation After phytohemagglutinm-induced activation of PBL, the number of T90/44 molecules per cell expressed at the cell surface rose from day 0 to day 7 by a factor of about 10 High concentrations of 9 3 mAb (5-10 \iglm\) at low cell densities and in the presence of monocytes in culture media supplemented by fetal calf serum were directly mitogemc for resting lymphocytes The cytolytic effector functions of class I-restncted cytotoxic Τ lymphocytes (CTL) were not modulated by 9 3 mAb The mixed lymphocyte reactions of three class I-restncted CTL to their specific target cells were found not to be significantly mfluenced by 9 3 mAb In conclusion it is proposed that an antigen-independent Τ cell activation pathway can be entered at T90/44 1 Introduction vitro finding that the tnggenng of the antigen reeeptor Ti/T3-antigen complex by appropnately presented antigen or by monoclonal antibodies (mAb) is capable of ehcitmg proliferative Τ cell responses (for review see [1, 2]) The discovery that two mAb directed to epitopes of the Tl 1 antigen in combination also can stimulate Τ cell growth [3] proved that additional, antigen-independent activation pathways exist More recently, it was found that yet another class of Τ cell surface molecules, T90/44, in response to the bmding of a specific hgand, can dnve Τ cells into prohferation T90/44 binds the 9 3 mAb [4], it is expressed at the surface of helper (T h ) and cytotoxic Τ cell subsets in the form of 90-kDa disulfide-bonded dimers of a 44-kDa polypeptide and of free 44-kDa subumts [5][6][7] The first indication that T90/44 may function in a new antigen-independent Τ cell activation pathway was provided by the discovery that 9 3 mAb strongly enhances prohferative cell responses to phytohemagglutimn (PHA) and allogeneic cells [5] This hypothesis was further supported by the more recent fmdings that 9 3 mAb also enhances the mitogemc response to 12-0-tetradecanoylphorbol 13-acetate and may act as a direct mitogen [7,8] To assess the functional role of T90/44 in more detail, we have investigated the effects ot 9 3 mAb in cell tulture assays with cloned antigen-specific helper cells as well as cytotoxic Τ cell hnes (CTL) and resting normal Τ cells Our results show that dependmg on the type of the cells in culture, positive or negative Signals can be mediated through T90/44, since the activation of helper cells by antigen was found to be inhibited by 9 3 mAb, whereas resting Τ cells may be activated by 9 3 mAb An important element in this funct...…”

Diagnosis of chronic myeloid and acute lymphocytic leukemias by detection of leukemia-specific mRNA sequences amplified in vitro.

“…The abnormality usually involves a reciprocal translocation of chromosomes 9 and 22 (2), and more than 95% of CML patients have this defect. The translocation involves the movement of most of the ABL protooncogene (3, 4) on chromosome 9 to the BCR or "breakpoint cluster region" gene on chromosome 22 (5).…”

“…The abnormality usually involves a reciprocal translocation of chromosomes 9 and 22 (2), and more than 95% of CML patients have this defect. The translocation involves the movement of most of the ABL protooncogene (3, 4) on chromosome 9 to the BCR or "breakpoint cluster region" gene on chromosome 22 (5). Expression of the fused genes results in a chimeric 8.5-kilobase (kb) mRNA transcript (6) and a large 210-kDa translation product, P210, with increased tyrosine kinase activity relative to the normal ABL protein (7).…”