Interleukin 2 (IL 2) inhibitor in rheumatoid synovial fluid: correlation with prognosis and soluble IL 2 receptor levels.

A soluble activity inhibiting over 50% of the CTLL-2 cell line response to recombinant human interleukin 2 (IL 2) was found in 17 of 29 (59%) rheumatoid synovial fluids. To study the prognosis value of this activity, 16 rheumatoid synovial fluids were collected before a radiation synovectomy of the knee with 7 mCi of 90Yt. Patients with a good clinical result after the synovectomy had a lower IL 2 inhibitory activity than those with a bad or incomplete result (P less than 0.01). Levels of inhibitory activity and of soluble IL 2 receptors were correlated with each other and with the response of the synovitis to the radiation synovectomy. These results extend the clinical usefulness of soluble IL 2 receptor measurements and indicate a correlation between the immune activation of the rheumatoid synovitis and its clinical activity.

Production of B-cell growth factor interleukin 2 and gamma interferon by peripheral blood lymphocytes from patients with chronic lymphocytic leukemia of B-cell type.

Chronic lymphocytic leukemia of B-cell type (B-CLL) is a malignant disease characterized by monoclonal proliferation of small lymphocytes of B-cell origin, usually associated with suppression of polyclonal B-cell activation (i.e., proliferation and differentiation). Normal human B-cell proliferation is controlled by different T-cell-derived lymphokines, including interleukin 2 (IL2) and gamma interferon (gamma-IFN), that account for the majority of the B-cell growth factor (BCGF) activity produced by mitogen-activated peripheral blood mononuclear cells (PBMCs). We have previously shown an increased and dysregulated secretion of IL2 in peripheral blood from patients with B-CLL. BCGF, IL2, and gamma-IFN productions by phytohemagglutinin (PHA)-stimulated PBMCs were investigated in 13 patients with active untreated B-CLL and 11 healthy donors. B-CLL PBMCs produced a significant amount of BCGF (6 U/ml) despite the low percentage of T cells (10%) associated with this disease as compared with that found in healthy donors (61%). BCGF production in normal controls and B-CLL patients was tripled after irradiation of PBMCs or addition of indomethacin. gamma-IFN secretion in B-CLL patients was decreased when compared with normal controls. Therefore, when gamma-IFN was calculated per fixed number of T cells, production was significantly higher in B-CLL patients than in normal controls, showing a dilution of the productive cells. This study suggests that T cells from B-CLL patients are functional in terms of BCGF production despite their decreased percentage and abnormalities in surface markers.

Enzyme immunoassay for human chorionic gonadotropin using monoclonal antibodies elicited with a synthetic peptide.

We recently described the generation of mouse monoclonal antibodies directed against hCG using a synthetic peptide immunogen: the carboxy-terminal peptide (CTP) of beta-hCG. The CTP, residues 109-145, is a portion unique to hCG and is not present in other glycoprotein hormones. These monoclonal antibodies react with beta-hCG-CTP and whole hCG but do not react with hLH. In the present study, a two-site sandwich ELISA specific for hCG has been developed using these CTP-induced monoclonal antibodies. Two monoclonal antibodies were paired: beta-hCG-CTP-a6 was immobilized to give a hCG-specific solid phase, and a biotinylated monoclonal antibody against beta-hCG was used as the indicator antibody. This second antibody was introduced during the hCG-capture step because of its agonist effect on hCG-capture by beta-hCG-CTP-a6 solid phase. This ELISA system can detect 2.2 IU/l hCG in a serum-free medium and 10.4 IU/l in a medium containing 20% human serum. We did not observe any cross-reactivity with hLH up to concentrations of 5000 IU/l. The hCG-ELISA correlated well (r = 0.99) with a control RIA in an assay of 78 human sera from healthy males, pregnant or non-pregnant females and from patients with choriocarcinoma, hydatidiform mole, or teratocarcinoma.

Non-cross-reactive monoclonal antibodies to human chorionic gonadotropin generated after immunization with a synthetic peptide.

Noncross-reactive monoclonal antibodies specific for human chorionic gonadotropin (hCG) were obtained after pre-selection for submolecular specificity with a synthetic peptide immunogen. Mice were immunized with a synthetic peptide representing a segment unique to the beta-subunit of hCG (amino acid residues 109-145), conjugated to diphtheria toxoid. We then derived nine different hybridomas that secreted monoclonal antibodies reactive with both native hCG and isolated C-terminal peptide, after somatic cell hybridization of immune spleen cells with a nonsecretory myeloma cell line. None of the nine monoclonal antibodies, termed beta-hCG-CTPa1----a9, reacted with hLH, hFSH, or hTSH, although these pituitary hormones display extensive amino acid sequence homology with hCG. The noncross-reactive anti-beta-hCG monoclonal antibodies show apparent association constants on the order of 10(9) to 10(10) M-1. A sandwich-type enzyme-linked immunosorbent assay was set up with cut-off values of around 5 mIU/ml. These antibodies might have important implications for: a) improving the diagnosis and clinical management of pregnancy; b) monitoring the course of development of carcinomas which secrete the hormone, through in vitro assays or in vivo radioimmunodetection; c) evaluating the antibodies' therapeutic potential against such carcinomas; d) studying the biologic functions of the C-terminal segment of beta-hCG; and e) addressing the anti-fertility effect of antibodies raised against that segment.

Human soluble Fc gamma-binding material. I. Immunochemical properties of the material produced by the T cell line KE37.

A soluble Fc gamma-binding material (S-Fc gamma BM) is produced by the Fc gamma receptor-bearing human T cell line KE37 but not by the two Fc receptor-negative cell lines Molt 4 and Reh 6. The S-Fc gamma BM has specific affinity for the Fc fragment of IgG and none for the Fab fragments. It can be obtained in radioactive form after internal labeling with radioactive amino acids. It can then be isolated from the supernatant of the KE37 cell line by affinity chromatography, gel filtration and isoelectric focusing. The subunit components of S-Fc gamma BM are 23,000-dalton polypeptide chains. The soluble form is a dimer (42,000 to 45,000 m.w., pl 6.2), which retains Fc gamma-binding activity after isolation. Higher m.w. polymers of the 23,000-dalton subunits are also present in the supernatant of the KE37 cell line. These polymers are relatively insoluble in aqueous solvents but possess Fc gamma-binding activity. The S-Fc gamma BM molecules might be derived from a membrane-inserted form by restricted proteolytic cleavage at connecting regions of a larger polypeptide chain folded into 23,000-dalton subunits.